JP6214489B2 - Signal processing apparatus and signal processing method - Google Patents

Description

  The present invention relates to a signal processing device and a signal processing method capable of measuring an electrical quantity related to AC power.

  For example, when measuring the amount of electricity related to AC power such as an electric power system, signal processing is performed based on a fast Fourier transform (FFT: also called discrete Fourier transform (DFT)) and a sampling theorem. It is common to use. On the other hand, this inventor has proposed the method of measuring various electric quantities using the group theory of symmetry theory (patent document 1 and patent document 2).

Japanese Patent No. 5214074 JP 2013-092473 A

IEEE Std. C37.118.1-2011, IEEE Standard for Synchrophasor Measurements for Power Systems A.G. Phadke, J.S.Thorp, M.G.Adamiak, “A New Measurement Technique For Tracking Voltage Phasors, Local System Frequency, And rate of Change of frequency”, IEEE TRANSACTIONS ON POWER APPARATUS AND SYSTEMS, 1983-05-01, pages 1025-1038

  The inventor of the present application has proposed a method of forming a symmetric group using one gauge sampling frequency. Compared with such a method, a new method with higher speed and accuracy has been invented. The present invention provides a new signal processing technique using the group theory of symmetry theory.

  In order to solve the above-described problems and achieve the object, a signal processing device according to an aspect of the present invention includes a collection unit that samples a measurement object at a collection sampling frequency and collects instantaneous value data in time series, and a plurality of collection units. First calculating means for calculating a gauge rotation phase angle corresponding to each of the gauge sampling frequencies. Each of the plurality of gauge sampling frequencies is a value obtained by dividing the collected sampling frequency by a positive integer, and the first calculation means refers to a conversion factor determined in advance separately for the gauge sampling frequency, Each gauge rotation phase angle is calculated from the sampled instantaneous value data.

  A signal processing method according to another aspect of the present invention includes a collection step of sampling a measurement object at a collection sampling frequency and collecting instantaneous value data in time series, and a gauge rotation phase angle corresponding to each of the plurality of gauge sampling frequencies. A first calculation step of calculating. Each of the plurality of gauge sampling frequencies is a value obtained by dividing the collected sampling frequency by a positive integer, and the first calculation step is performed by referring to a predetermined conversion factor for each of the gauge sampling frequencies. Calculating a respective gauge rotation phase angle from the sampled instantaneous value data.

  According to the present invention, a new signal processing technique using the group theory of symmetry theory with higher speed and accuracy is provided.

It is a schematic diagram for demonstrating the synchronous phasor on a complex plane. It is a schematic diagram for demonstrating the gauge rotation phase angle on a complex plane. It is a conceptual diagram for demonstrating the multiscale method. It is a schematic diagram for demonstrating the symmetry of a gauge rotation phase angle and a real frequency. It is a figure which shows the gauge voltage group on a complex plane. It is a figure which shows the gauge difference voltage group on a complex plane. It is a figure which shows the relationship between the number of gauge sampling points in a data collection sampling frequency 4000Hz, and a gauge sampling period. It is a figure which shows the relationship between the number of gauge sampling points in the data collection sampling frequency 4000Hz, and a gauge sampling frequency. It is a figure which expands and shows the relationship between the number of gauge sampling points in the data collection sampling frequency 4000Hz shown in FIG. 8, and a gauge sampling frequency. It is a figure which shows the relationship of the proportionality coefficient of the real frequency and the gauge sampling frequency with respect to the number of gauge sampling points in the data collection sampling frequency of 4000 Hz. It is a figure which shows the relationship of the proportionality coefficient of a gauge sampling frequency and an actual frequency with respect to the number of gauge sampling points in the data collection sampling frequency of 4000 Hz. It is a figure which shows the relationship between the number of gauge sampling points in the data collection sampling frequency 4000Hz, and the frequency coefficient in the real frequency 50Hz. It is a figure which shows the relationship between the gauge sampling point in the data collection sampling frequency 4000Hz, the gauge rotation phase angle in the real frequency 50Hz, and a measurement rotation phase angle. It is a graph showing a relationship between a frequency conversion coefficient _{k f1} and _{k f2} in gauge sampling points and the actual frequency 50Hz in the data collection sampling frequency 4000 Hz. It is a figure for demonstrating the optimal value of the measurement rotation phase angle in the data collection sampling frequency 4000Hz and the real frequency 50Hz. It is a figure for demonstrating the estimation method of the fundamental wave frequency at the present. 2 is a schematic diagram illustrating a configuration example of a signal processing device according to Embodiment 1. FIG. 3 is a flowchart illustrating a processing procedure executed by the signal processing apparatus according to the first embodiment. It is a figure which shows the simulation result about the voltage instantaneous value and voltage effective value in the fundamental wave simulation of case 1. FIG. 6 is a diagram illustrating a simulation result of an instantaneous frequency in the fundamental wave simulation of case 1. 6 is a diagram illustrating a time waveform of an observed voltage in an actual measurement example of case 2. FIG. It is a figure which shows the spectrum calculation result obtained by FFT with respect to the time waveform of the observation voltage in the actual measurement example of case 2. It is a figure which expands and shows the range of 0-840 [Hz] of the spectrum shown in FIG. It is a figure which expands and shows the range of 0-420 [Hz] of the spectrum shown in FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 1 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 2 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 3 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in the number of gauge sampling points _Ng = 12, in the actual measurement example of case 2. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 17 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 117 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 217 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 317 in the actual measurement example of case 2. FIG. It is a figure which shows the measurement result of the instantaneous frequency in gauge sampling point number _Ng = 417 in the actual measurement example of case 2. FIG. FIG. 10 is a diagram showing a measurement result of an instantaneous frequency at the number of gauge sampling points N _g = 983 in an actual measurement example of case 2. FIG. 6 is a diagram showing a distribution curve of instantaneous frequency at each gauge sampling point in an actual measurement example of case 2. The enlarged view of the distribution curve of the instantaneous frequency shown in FIG. 35 is shown. FIG. 10 is a diagram showing a measurement result of an average frequency at the number of gauge sampling points N _g = 1, 2, 3, 12 in an actual measurement example of Case 2. It is a graph showing measurement results of the average frequency of a gauge number of sampling points N _{g =} 17, 117 in the actual example of the case 2. It is a figure which shows the measurement result of the voltage amplitude in gauge sampling point number _Ng = 17 in the actual measurement example of case 2. FIG. It is a figure which shows the direct-current component measurement result in gauge sampling point number _Ng = 17 in the actual measurement example of case 2. FIG. It is a figure which shows the gauge synchronous phasor group on a complex plane. It is a figure which shows the gauge difference synchronous phasor group on a complex plane. 6 is a schematic diagram illustrating a configuration example of a synchronized phasor measuring device according to Embodiment 2. FIG. 6 is a flowchart illustrating a processing procedure executed by the synchronized phasor measuring device according to the second embodiment. FIG. 6 is a diagram showing a simulation result for a synchronized phasor in a fundamental wave simulation of case 3. FIG. 10 is a diagram illustrating a simulation result of a synchronized phasor phase angle in a fundamental wave simulation of case 3. FIG. 10 is a diagram showing simulation results for a time-synchronized phasor in a fundamental wave simulation of case 3. FIG. 6 is a diagram illustrating a measurement result of a synchronized phasor in an actual measurement example of case 4. It is an enlarged view of the measurement result of the synchronous phasor shown in FIG. FIG. 6 is a diagram illustrating a measurement result of a synchronized phasor phase angle in an actual measurement example of case 4. FIG. 6 is a diagram illustrating a measurement result of a time synchronization phasor in an actual measurement example of case 4. FIG. 6 is a diagram illustrating a measurement result of a time synchronization phasor in an actual measurement example of case 4. It is a figure which shows the gauge electric power group on a complex plane. It is a figure which shows the gauge difference electric power group on a complex plane. It is a figure which shows the gauge double voltage group on a complex plane. It is a figure which shows the gauge difference twin voltage group on a complex plane.

  A signal processing apparatus and a signal processing method according to embodiments of the present invention will be described below with reference to the accompanying drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated. In addition, this invention is not limited by embodiment shown below.

[A. Background art and overview]
The technique proposed by the inventors of the present invention in Patent Document 1 and Patent Document 2 is a technique using one gauge sampling frequency. This method using one gauge sampling frequency is referred to as a “single scale method” for comparison with the present application. In contrast, in the present application, a technique of using a plurality of gauge sampling frequencies newly found by the inventor of the present application is adopted. The new method described in the following description is referred to as “multi-scale method” for convenience. Note that the naming of this method is merely for convenience of explanation, and the technical scope of the present invention should be determined based on the description of the claims.

  In the multi-scale method of the present embodiment, by simultaneously measuring using a plurality of gauge sampling frequencies, it is freed from the constraint of the sampling theorem, for example, an unspecified number of harmonic components of an actual waveform in power system fundamental wave measurement etc. Can significantly reduce the effects of

  A schematic theoretical explanation of the multi-scale method of the present embodiment will be given. In the conventional FFT, the target waveform is decomposed and separated into frequency components. On the other hand, the multi-scale method integrates the target waveform into one symmetric fundamental wave using the group theory of symmetry theory.

  When a fundamental wave that does not contain harmonic components is measured by the multiscale method, the same analytical solution can be obtained at all scales. On the other hand, in FFT, only an approximate solution can be obtained in the measurement of the fundamental wave, no matter how much the sampling frequency is increased. This is a significant difference between the multi-scale method and FFT. In addition, the amount of calculation is smaller in the multi-scale method, and faster calculation can be performed.

  In the electric power system, disturbances may occur due to various factors such as system faults, load on / off, weather changes, and events. For the processing of voltage flicker, which is a relatively large disturbance, symmetry breaking indices for all scales are provided. As a result, the scale that generates data away from the fundamental wave is excluded from the corresponding symmetric group and the frequency is not calculated. This makes it possible to distinguish between partial disturbances and power outages. In addition, in the additive noise (harmonic) processing, the influence of noise is reduced by performing averaging processing for each scale in all scales.

  In the multi-scale method, when the gauge sampling frequency is small, the measurement result of the instantaneous frequency and the measurement result of the average frequency deviate from the fundamental wave, but the measurement result of one average frequency corresponding to one scale is obtained. The smaller the scale, the higher the average frequency measurement result obtained. By utilizing this, it can be used for an apparatus that can determine the state of isolated operation at high speed.

  In contrast, one of the merits of FFT is that each frequency component including the fundamental wave component of the actual waveform can be analyzed. However, the FFT calculation requires a lot of data, and the calculation time becomes long.

  The multi-scale method avoids aliasing phenomenon caused by FFT by using a frequency calculation reference table.

  As described above, it is necessary to perform measurement while maintaining high speed and high accuracy in processing that requires high real-time properties such as control protection of the power system, and the multiple scale method of the present embodiment is used. The benefits of using it are enormous. On the other hand, FFT can be used as a powerful auxiliary tool because it can calculate each harmonic component of the actual waveform in offline post-mortem analysis. The following table shows the comparison results of the merits and demerits between the multi-scale method of this embodiment and FFT.

  Next, the multi-scale method of the present embodiment will be described in comparison with a conventional power system analysis theory. According to Non-Patent Document 1 (see Equation (7) on page 8), the fundamental wave is defined as the following Equation (1).

x (t) = X _m cos [Ψ (t)] (1)
Furthermore, according to Non-Patent Document 1 (see equation (8) on page 8), the frequency is defined as the following equation (2).

  According to the IEEE definition disclosed in Non-Patent Document 1, the phase angle Ψ (t) is first measured, and then the fundamental frequency is measured. According to the conventional theory, the fundamental wave is extracted using FFT for the measurement of the phase angle Ψ (t) (Non-patent Document 2).

  Unlike the definition in the conventional theory, the multiscale method of the present embodiment first introduces multiple gauge spaces according to the group theory method, performs frequency measurement in each gauge space, and affects the influence of harmonic components. The measurement result of the fundamental wave with greatly reduced is obtained. Then, voltage amplitude, synchronized phasor, time synchronized phasor (phase difference), spatially synchronized phasor (phase difference angle), etc. are measured according to the same group theory method using the measurement result of the stable fundamental wave frequency. As described above, in the multiscale method of the present embodiment, measurement is performed with the fundamental wave as the center, whereas in the conventional theory, substantially all frequency components are handled equally by using FFT. become. By measuring with the fundamental wave as the center, the multiscale method of the present embodiment can measure the quantity of electricity at higher speed and with higher accuracy.

  The measurement of the amount of electricity (AC voltage current or DC voltage current) of the power system is essentially signal processing of time series data, which is the same as general signal processing. That is, the multi-scale method of the present embodiment is not limited to the measurement of the electric quantity of the power system, but can be applied to various time waveforms and signal processing.

  As described above, in the basic part, there are many points that are different from the technique previously proposed by the inventor of the present application, so the terms used in the present application will be explained first.

[B. Definition of terms]
First, terms used in this specification will be described in describing the signal processing device and the signal processing method of the present embodiment.

(1) Rotation vector, complex number, complex plane In the present embodiment, a rotation vector on a complex plane is simulated using a complex number. The complex number z is defined according to the following equation (3).

z = a + jb (3)
However, j = √ (−1) is an imaginary unit. In general, an imaginary unit is defined as i = √ (−1). Since i is a current code in electrical engineering, j is used as a code indicating an imaginary unit.

(2) group theory
Includes mathematical theories to study symmetry.

(3) Symmetry group
By a group composed of multiple vectors having symmetry rotating on the complex plane, or by multiple vectors having symmetry stationary on the complex plane Includes configured groups.

(4) Invariant
Invariants are the properties of systems that a symmetric group has that does not change under certain transformations. Invariants assumed in the present embodiment are not limited to these, but are not limited to gauge rotation phase angle, measurement rotation phase angle (rotation phase angle), measurement frequency coefficient (frequency coefficient), gauge voltage, and gauge difference. Voltage, Gauge Effective Synchronized Phaser, Gauge Invalid Synchronized Phaser, Gauge Differential Effective Synchronized Phaser, Gauge Differential Invalid Synchronized Phaser, Gauge Active Power, Gauge Reactive Power, Gauge Differential Active Power, Gauge Differential Reactive Power, Gauge Effective Dual Voltage, Gauge Invalid Dual Voltage, gauge differential effective dual voltage, gauge differential invalid dual voltage, etc. If the invariants are known, the characteristics of the symmetric group can also be known.

(5) Single scale method
For example, the measurement method proposed by the present inventor in Patent Document 1 and the like. In summary, it is directed to a technique for measuring the fundamental frequency using one gauge sampling frequency that is greater than the fundamental frequency.

(6) Multiscale method
It should also be called a frequency calculation reference table method, and is developed from the single scale method previously proposed by the present inventor, and is directed to a method of simultaneously measuring electricity using a plurality of gauge sampling frequencies. . As will be described later, there is no lower limit of the gauge sampling frequency. A frequency calculation reference table is generated in advance from the set data collection sampling frequency (for example, 4000 Hz) and the system rated frequency (for example, 60 Hz). In the measurement process, a plurality of gauge sampling frequencies are selected, the actual frequency is assumed to be the system rated frequency, the corresponding coefficient is obtained from the frequency calculation reference table, and the actual frequency is calculated. In the measurement of the unspecified fundamental wave, the closest fundamental wave measurement value obtained at a different scale is used by simultaneous calculation using a plurality of frequency calculation reference tables. In the following description, a specific number of gauge sampling points is also referred to as “scale”.

(7) System nominal frequency
It means a rated frequency in the power system, and is typically 50 Hz or 60 Hz.

(8) Actual frequency This means the actual frequency in the electric circuit. In the case of an actual power system, the actual frequency frequently fluctuates around the rated frequency. In the following, the actual frequency is expressed by the symbol f, and its unit is hertz (Hz). On the other hand, the real cycle is expressed by a code T, and its unit is seconds (s). The real period T is defined according to the following equation (4).

T = (1 / f) (s) (4)
Further, the actual angular frequency in the electric circuit is expressed by the symbol ω, and its unit is radians per second (rad / s). The angular frequency ω is defined according to the following equation (5).

ω = 2πf (rad / s) (5)
(9) Amplitude and root mean square
The amplitude means the maximum value of the alternating voltage (or alternating current) and corresponds to the length of the rotation vector on the complex plane. The effective value is obtained by dividing the amplitude (maximum value) by √2.

(10) Data collecting rate
Sampling frequency at the time of data collection, the higher the better. The data collection sampling frequency is expressed by the symbol f ₁ and its unit is hertz (Hz). On the other hand, the data collection sampling period is represented by a reference numeral T _1, and the unit is seconds (s). Data collection sampling period T ₁ are defined according to the following equation (6).

T ₁ = (1 / f ₁ ) (s) (6)
Further, the data collection rotation phase angle corresponding to the data collection sampling period T ₁ is expressed by the symbol α ₁ .

(11) Gauge sampling frequency
A sampling frequency used in the calculation of the gauge symmetry group, represented by the symbol f _g, the unit is the Hertz (Hz). On the other hand, the gauge sampling period is expressed by a symbol _Tg , and its unit is seconds (s). The gauge sampling period _Tg is defined according to the following equation (7).

T _g = (1 / f _g ) (s) (7)
Note that, unlike the technique disclosed in Patent Document 1, a plurality of gauge sampling frequencies are used in the present embodiment. The maximum value of the gauge sampling frequency is equal to the data collection sampling frequency.

(12) Number of gauge sampling points (scale)
It means a number of data acquisition sampling corresponding to the gauge rotational phase angle (a positive integer), expressed by symbol N _g.

(13) Measurement frequency coefficient This means the cosine function value of the measured rotational phase angle, and is defined according to the following equation (8).

f _C = cos α (8)
From the equation (8), it can be seen that the absolute value of the measurement frequency coefficient is 1 or less. In the following description, the measurement frequency coefficient is also simply referred to as “frequency coefficient” for simplification.

(14) Measurement rotational phase angle This means the inverse cosine function value of the frequency coefficient, and its unit is radians (rad). The measured rotational phase angle is defined according to the following equation (9).

α = cos ⁻¹ f _C (9)
From the equation (9), it can be seen that the range that the measured rotational phase angle can take is 0 to π radians. In the following description, for the sake of simplicity, the measured rotational phase angle is also simply referred to as “rotational phase angle”.

(15) Gauge rotation phase angle
The rotation vector rotating on the complex plane means the angle actually rotated in the gauge sampling period, and is expressed by the symbol α _g .

(16) Frequency calculation reference table Mainly means a coefficient table adopted by the multiscale method of the present embodiment in order to avoid the influence of aliasing phenomenon caused by fast Fourier transform (FFT). Typically, each coefficient is calculated in advance by associating the data collection sampling frequency with the system rated frequency. Typically, the frequency calculation reference table is stored in the signal processing apparatus and is referred to as appropriate. When the gauge sampling frequency is lower than the actual frequency (assumed to be in the range of ± several Hz relative to the system rated frequency), refer to the corresponding coefficient in the frequency calculation reference table, and measure the measured rotation phase angle to the gauge rotation phase angle. Convert to, and measure the actual frequency. It is preferable to prepare a plurality of frequency calculation reference tables in advance so that an unspecified fundamental wave can be measured.

(17) and the frequency conversion factor gauge rotational phase angle and the rotation phase angle is related to the frequency conversion factor _{k f1} and _{k f2.} The frequency coefficient k _f1 is a positive integer that changes stepwise, and the frequency coefficient k _f2 takes a value of 1 or −1.

(18) Symmetry breaking When the absolute value of the calculation result of the frequency coefficient of the symmetry group is larger than 1, it is determined that the symmetry of the symmetry group is broken.

(19) Instantaneous frequency Unlike the definition in the conventional theory expressed by the above equation (2), the definition in the multiscale method of the present embodiment is a gauge calculated by the frequency coefficient of a symmetric group of one scale. It means the frequency calculated from the rotational phase angle. When a harmonic component is included in the measurement target, the measurement results of the instantaneous frequency of different scales are different from each other. In each embodiment described below, calculation is performed using a gauge differential voltage group as a typical example.

(20) Average frequency This means an average value of instantaneous frequencies, and is typically calculated by moving average processing.

(21) consecutive time intervals gauge voltage group means a symmetric group constituted by three voltage rotation vector is T _g. The actually measured voltage instantaneous value corresponds to the real part of the voltage rotation vector, and the unit of the voltage is volts (V).

(22) consecutive time intervals gauge differential voltage group means a symmetric group constituted by three differential voltage rotation vector is T _g.

(23) gauge synchronized phasor successive time intervals group means a symmetric group constituted by three voltage rotation vector and three unit vectors are T _g.

(24) consecutive time intervals gauge differential synchronization phasor group means a symmetric group constituted by three differential voltage rotation vector and three differential unit vectors a T _g.

(25) consecutive time intervals gauge power group means a symmetric group constituted by three voltage rotation vector and three current rotation vector is T _g. Using the gauge power group, active power (unit: watt (W)), reactive power (unit: volt ampere (VA))), apparent power (unit: volt ampere (VA)), resistance (unit: ohm ( Ω)), reactance (unit: ohm (Ω)), etc.

(26) consecutive time intervals gauge differential power group means a symmetric group constituted by three differential voltage rotation vector and three differential current rotation vector is T _g. The gauge differential power group can be used to perform the same calculation as the gauge power group without being affected by the DC offset.

(27) gauge bi voltage successive time intervals group means a symmetric group constituted by three voltage rotation vector three voltage rotation vector and another terminal of the three is the terminal of a T _g. Using the symmetry of the gauge dual voltage group, the phase difference angle between two vectors rotating at the same angular velocity (ie, frequency) can be measured.

(28) Gauge differential dual voltage group This means a symmetric group composed of three differential voltage rotation vectors of three terminals having continuous time intervals of _Tg and three differential voltage rotation vectors of another terminal. Using the symmetry group of the gauge differential dual voltage group, the phase difference angle between two vectors rotating at the same angular velocity (ie, frequency) can be measured without being affected by the respective DC offsets.

(29) Isolated operation discriminating device Isolated operation is a state in which an accident or the like occurs in a power system in which a plurality of distributed power sources are connected, and the distributed power source is disconnected from the system power source. This means that power generation is continued only by operating the distributed power supply. The isolated operation determination device determines such an isolated operation state and shuts off the distributed power supply.

(30) Synchronous phasor This means a vector rotating on the complex plane. A synchronized phasor is typically defined by three quantities: voltage amplitude, synchronized angular velocity (ie, frequency), and synchronized phasor phase angle.

(31) Synchronous phasor measurement unit (PMU: Phasor Measurement Unit)
It is a device that measures synchronous phasors.

(32) Time-synchronized phasor This means the difference in synchronized phasor phase angle at different time sections at the same terminal.

(33) Spatial synchronized phasor This means a difference in synchronized phasor phase angle at different terminals in the same time section, and is also called a phase difference angle.

[C. Multiscale algorithm]
An outline of the algorithm of the multiscale method of the present embodiment will be described.

  The actual voltage waveform of the power system can be defined using a vector expression as shown in the following equation (10).

  As shown in the equation (10), the actual voltage waveform is composed of a DC component, a fundamental wave, and a plurality of harmonic components. In the multiscale method of the present embodiment, a symmetric group defined by a difference amount such as a gauge differential voltage group is used in order to reduce the influence of a direct current component (details will be described later). Note that the DC component can be calculated using a gauge voltage group.

  In the following, attention is focused on the influence of harmonic components. Before explaining the influence of harmonic components, first, the definition of the synchronized phasor, which is the fundamental wave, is clarified.

  FIG. 1 is a schematic diagram for explaining a synchronized phasor on a complex plane. With reference to FIG. 1, a synchronous phasor is defined as a rotation voltage vector as shown in the following equation (11).

v1 (t) = Ve ^{j (ωt + φ)} (11)
In the equation (11), V is an AC voltage amplitude, ω is an angular velocity, and φ is a synchronized phasor phase angle. As disclosed in Patent Document 1 described above, the AC voltage amplitude and the angular velocity (frequency) are obtained by a gauge voltage group or a gauge differential voltage group, and the synchronized phasor phase angle is obtained by a gauge synchronized phasor group or a gauge differential synchronized phasor group. Is required.

  In the method disclosed in Patent Document 1, the range of the rotational phase angle is limited to 0 to π and −π to 0, and thus the influence of harmonic components may not be sufficiently reduced. In contrast, in the present embodiment, a physical quantity corresponding to the rotational phase angle in the method disclosed in Patent Document 1 is redefined and used as a “gauge rotational phase angle”. The range of the gauge rotation phase angle is a positive number exceeding 0 (the upper limit is arbitrarily set). As will be described with reference to FIGS. 2 to 4, the gauge rotation phase angle introduced in the present embodiment has symmetry as well as the rotation phase angle in the technique disclosed in Patent Document 1. And group theory can be applied.

  That is, the basic idea of the multiscale method of the present embodiment is to use the symmetry between the gauge rotation phase angle and the actual frequency as shown in FIGS.

  FIG. 2 is a schematic diagram for explaining the gauge rotation phase angle on the complex plane. FIG. 3 is a conceptual diagram for explaining the multi-scale method. FIG. 4 is a schematic diagram for explaining the symmetry between the gauge rotation phase angle and the actual frequency.

  First, when the phase angle shown in FIG. 1 is compared with the phase angle shown in FIG. 2, at first glance, both appear to express the same technical idea, but the two phase angles are different technologies. Has significant significance. First, the difference between the gauge rotation phase angle and the synchronized phasor phase angle will be described.

First, assuming that the power system frequency is constant, the gauge rotation phase angle α _g corresponding to the gauge sampling period T _g shown in FIG. 2 is invariant, while the synchronized phasor phase angle φ shown in FIG. To change. Further, regarding the range where the value can be taken, the range of the gauge rotation phase angle α _g is a positive number up to the upper limit set value exceeding 0, but the range of the synchronized phasor phase angle φ is −180 ° to + 180 °. Range.

Intuitively, on the complex plane of FIG. 2, the real period T, the gauge rotation phase angle α _g , and the gauge sampling period T _g have a relationship as shown in the following equation (12).

Each of the three states depending on the magnitude of the gauge rotation phase angle α _g shown in FIG. 2 will be described.

(A) When Gauge Rotation Phase Angle α _g <180 ° If the voltage rotation vector is rotated by 2π after a lapse of T time, the voltage rotation vector is rotated by a phase angle α _g after the lapse of T _g time. According to the technique disclosed in Patent Document 1, the gauge rotation phase angle α _g can be obtained using group theory, and the real period T and the real frequency f can be obtained. In this case, the measurement range is the same as the existing sampling theorem.

(B) When 180 ° <Gauge Rotation Phase Angle α _g <360 ° If the voltage rotation vector is rotated by 2π after a lapse of T time, it will be rotated by a phase angle α _g after the lapse of T _g time. In the technique disclosed in Patent Document 1, the actual period T and the actual frequency f can be obtained by designating the measured rotation phase angle α as a negative rotation angle. In the multiscale method of the present embodiment, the concept of the negative rotation phase angle is abandoned, and the gauge rotation phase angle is obtained from a frequency calculation reference table generated in advance. The value of the gauge rotation phase angle is a positive number exceeding 0 ( The upper limit is arbitrarily set).

(C) When Gauge Rotation Phase Angle α _g > 360 ° If the voltage rotation vector rotates by 2π after a lapse of T time, it will rotate by a phase angle α _g after the lapse of T _g time. Also in this case, a symmetric group can be constructed by three voltage rotation vectors, and an invariant can be obtained by group theory operation.

  However, when the instantaneous frequency is calculated according to the method disclosed in Patent Document 1, a calculation result different from the actual frequency may be obtained (aliasing phenomenon).

  Therefore, in the multiscale method of the present embodiment, the influence of the aliasing phenomenon can be avoided by using the frequency calculation reference table. Therefore, when the gauge sampling frequency is smaller than the actual frequency, the gauge rotation phase angle is obtained by referring to the frequency calculation reference table from the measured rotation phase angle α.

  Therefore, in any of the above three cases, it is defined according to the following equation (13).

Where f is the actual frequency, α _g is the gauge rotation phase angle, and f _g is the gauge sampling frequency. From the equation (13), the actual frequency f is calculated according to the following equation (14).

The basic concept of the multiscale method of the present embodiment is to simultaneously measure an electric quantity (for example, power system frequency) using different gauge sampling frequencies. FIG. 3 shows two gauges composed of gauge sampling periods T _g2 and T _g4 each having a period twice and four times the gauge sampling period T _g1 (= data collection sampling period T ₁ ) of the fundamental wave. Indicates a voltage group. These gauge voltage groups are shown as shown in the following equation (15).

Next, the symmetry between the gauge rotation phase angle and the actual frequency will be described. In general, in the sampling theorem, the sampling frequency f _sampling and the actual frequency f to be measured need to satisfy the conditions as shown in the following equation (16).

That is, when the calculation is performed using the sampling frequency f _sampling larger than the actual frequency f, an aliasing phenomenon occurs, and the measurement cannot be performed correctly. In the multi-scale method, if the calculation is performed as it is, the aliasing phenomenon also occurs. Therefore, in the multiple scale method of the present embodiment, the aliasing phenomenon is avoided by using a frequency calculation reference table.

[D. Generation procedure of frequency calculation reference table]
Next, a procedure for generating a frequency calculation reference table used in the multiscale method of the present embodiment will be described. First, the gauge voltage group and the gauge differential voltage group necessary for generating the frequency calculation reference table will be described. As will be described below, by using these symmetry groups, invariants that are parameters whose values do not change before and after the symmetry group rotates are calculated.

(D1: gauge voltage group)
FIG. 5 is a diagram illustrating gauge voltage groups on the complex plane. Referring to FIG. 5, assuming that there is no DC component V _DC , three voltage rotation vectors on the complex plane are defined according to the following equation (17).

Where V is the AC voltage amplitude, ω is the rotational angular velocity, T _g is the gauge sampling period, and α _g is the gauge rotational phase angle at T _g . Unlike methods disclosed in Patent Document 1, the gauge sampling period The T _g is a positive number of limit without. Similar considerations apply to the calculation of other symmetric groups described below.

  Similar to the technique disclosed in Patent Document 1, a vector group table of gauge voltage groups can be created, and the symmetry of gauge voltage groups can be considered. Since the method of the consideration is disclosed in Patent Document 1, detailed description will not be repeated.

  The real part instantaneous value of the voltage rotation vector of the gauge voltage group shown in FIG. 5 is calculated according to the following equation (18).

  Re in the above equation (18) indicates the real part of the complex number. The real number group table of the gauge voltage group is shown in the following table.

Using this real group table, various invariants of the gauge voltage group can be calculated. As a typical example of such an invariant, a calculation formula for a frequency coefficient and a gauge voltage is shown below. That is, the frequency coefficient f _C and the gauge voltage V _g are calculated according to the equations (19) and (20), respectively.

  The AC voltage amplitude V is calculated according to the following equation (21) using these invariant equations.

Next, a method for calculating a direct current component using a gauge voltage group will be described. Considering the case where the direct current component _VDC shown in FIG. 5 exists, a calculation formula for the direct current component is derived. The instantaneous voltage value is obtained by adding the direct current component _VDC to the above-described equation (18), and is calculated according to the following equation (22).

By substituting the voltage instantaneous values shown in the equation (22) into the above equations (19) and (20), the equation (23) is derived as the frequency coefficient f _C in consideration of the DC component _VDC . From the equation (23), the equation (24) indicating the direct current component _VDC is obtained.

The frequency coefficient f _C shown in the equation (24) is obtained from a gauge differential voltage group that is not affected by the DC component. Hereinafter, the gauge differential voltage group will be described.

(D2: gauge differential voltage group)
FIG. 6 is a diagram illustrating a group of gauge differential voltages on the complex plane. Referring to FIG. 6, three differential voltage rotation vectors on the complex plane are defined according to the following equation (25).

Where V is the AC voltage amplitude, ω is the rotational angular velocity, T _g is the gauge sampling period, and α _g is the gauge rotational phase angle at T _g .

  Similar to the technique disclosed in Patent Document 1, a vector group table of gauge differential voltage groups can be created to consider the symmetry of the gauge differential voltage group. Since the method of the consideration is disclosed in Patent Document 1, detailed description will not be repeated.

  The real part instantaneous value of the differential voltage rotation vector of the gauge differential voltage group shown in FIG. 6 is calculated according to the following equation (26).

  Re in the above equation (26) represents the real part of the complex number. The real number group table of the gauge differential voltage group is shown in the following table.

Using this real group table, various invariants of the gauge differential voltage group can be calculated. As a typical example of such an invariant, a calculation formula for a frequency coefficient and a gauge voltage is shown below. That is, the frequency coefficient f _C and the gauge differential voltage V _gd are calculated according to the equations (27) and (28), respectively.

  The AC voltage amplitude V is calculated according to the following equation (29) using these invariant equations.

Since the gauge differential voltage V _gd is calculated from the difference between the instantaneous voltage values, high-speed and high-precision measurement is possible without being affected by the direct current component included in the voltage waveform.

The voltage effective value V _rms is calculated from the AC voltage amplitude V according to the following equation (30).

(D3: Creation of frequency calculation reference table)
A procedure for generating a frequency calculation reference table for realizing the multi-scale method of the present embodiment will be described using the concept of the gauge voltage group and the gauge differential voltage group described above.

As an example, the data collection sampling frequency f ₁ is assumed to be 4000 Hz, and the actual frequency f is assumed to be 50 Hz, the same as the system rated frequency.

(I) Gauge sampling period The relational expression shown in the following expression (31) is established between the gauge sampling period and the number of gauge sampling points.

However, T _g is the gauge sampling period, N _g is the gauge sampling points, T ₁ is the data collection sampling period, f ₁ is the data collection sampling frequency.

FIG. 7 is a diagram showing the relationship between the number of gauge sampling points and the gauge sampling period at a data collection sampling frequency of 4000 Hz. As shown in FIG. 7 and (31) below, as the gauge number of sampling points N _g is large, the gauge sampling period The T _g increases.

(Ii) Gauge sampling frequency The relational expression shown in the following equation (32) is established between the gauge sampling frequency and the number of gauge sampling points.

However, _fg is a gauge sampling frequency and _Tg is a gauge sampling period. That is, each of the plurality of gauges sampling frequency f _g is a value obtained by dividing the collected sampling frequency a positive integer.

FIG. 8 is a diagram showing the relationship between the number of gauge sampling points and the gauge sampling frequency at a data collection sampling frequency of 4000 Hz. FIG. 9 is an enlarged view showing the relationship between the number of gauge sampling points and the gauge sampling frequency at the data collection sampling frequency of 4000 Hz shown in FIG. As shown in FIGS. 8, 9 and (32), the gauge sampling frequency f _g decreases as the gauge sampling point number N _g increases. It can be seen that the characteristic curves shown in FIGS. 8 and 9 are very non-linear, and are saturated when the gauge sampling frequency _fg is below a certain value.

The coefficient actual frequency f and the gauge sampling frequency f _g of the (iii) actual frequency and the gauge sampling frequency, the gauge number of sampling points, equation is satisfied as shown in the following equation (33).

However, _Tg is a gauge sampling period and _Ng is the number of gauge sampling points.
FIG. 10 is a diagram showing the relationship of the proportional coefficient between the actual frequency and the gauge sampling frequency with respect to the number of gauge sampling points at the data collection sampling frequency of 4000 Hz. As shown in FIGS. 10 and (33), the proportional coefficient K _fg between the actual frequency f and the gauge sampling frequency f _g increases as the number of gauge sampling points N _g increases.

(Iv) Coefficient of Gauge Sampling Frequency and Actual Frequency The gauge sampling frequency _fg and the actual frequency f satisfy the relational expression shown in the following equation (34) for the number of gauge sampling points.

However, _Tg is a gauge sampling period and _Ng is the number of gauge sampling points.
FIG. 11 is a diagram showing the relationship of the proportional coefficient between the gauge sampling frequency and the actual frequency with respect to the number of gauge sampling points at the data collection sampling frequency of 4000 Hz. As shown in FIGS. 11 and (34), the proportional coefficient K _gf between the gauge sampling frequency f _g and the actual frequency f decreases as the number of gauge sampling points N _g increases.

(V) Frequency coefficient FIG. 12 is a diagram showing the relationship between the number of gauge sampling points at a data collection sampling frequency of 4000 Hz and the frequency coefficient at an actual frequency of 50 Hz. With different gauge sampling points N _g, when calculating the frequency coefficient f _C of the gauge voltage group or gauge differential voltage group mentioned above, is shown in Figure 12. Thus, the absolute value of the frequency coefficient f _C is smaller than 1.

(Vi) Gauge Rotation Phase Angle and Measurement Rotation Phase Angle FIG. 13 is a diagram showing the relationship between the number of gauge sampling points at a data collection sampling frequency of 4000 Hz and the gauge rotation phase angle and measurement rotation phase angle at an actual frequency of 50 Hz. For convenience of explanation, in FIG. 13, the phase angle is expressed in degrees (°), but radians (rad) are used in the actual calculation.

  The following relational expression (35) is established between the gauge rotation phase angle and the number of gauge sampling points.

The measured rotational phase angle α is calculated by the inverse cosine function of the frequency coefficient f _C. As shown in FIG. 13, the measured rotational phase angle α increases in the range of 0 ° to 180 °, and then reverses and decreases in the range of 180 ° to 360 ° (0 °). Thereafter, the same behavior is repeated.

(Vii) Frequency conversion coefficient Frequency conversion coefficients _kf1 and _kf2 indicating the relationship between the gauge rotation phase angle and the rotation phase angle shown in FIG. 13 are introduced. Using the frequency conversion coefficients k _f1 and k _f2 , the relationship between the gauge rotation phase angle α _g and the rotation phase angle α is defined as the following equation (36). That is, each gauge rotation phase angle is calculated from instantaneous value data sampled at the collected sampling frequency with reference to a predetermined conversion factor for each gauge sampling frequency.

The frequency conversion coefficient k _f1 is a function that increases stepwise, and the frequency conversion coefficient k _f2 is a binary function that takes a value of 1 or −1.

FIG. 14 is a diagram showing the relationship between the number of gauge sampling points at a data collection sampling frequency of 4000 Hz and the frequency conversion coefficients k _f1 and k _f2 at an actual frequency of 50 Hz.

(Viii) Optimal rotational phase angle When only the fundamental wave is included in the quantity of electricity to be measured, all the gauge sampling points shown in FIGS. 7 to 14 can be used. However, the fundamental wave changes in an actual power system. As a result of research using simulations, it has been found that when the rotational phase angle is 90 °, the influence of harmonic components included in the fundamental wave measurement can be reduced most. The result is shown in FIG. FIG. 15 is a diagram for explaining the optimum value of the measured rotational phase angle at a data collection sampling frequency of 4000 Hz and an actual frequency of 50 Hz.

  Therefore, an optimal measurement rotation phase angle is selected so that the measurement rotation phase angle (rotation phase angle) is as close to 90 ° as possible.

(Ix) Example of Frequency Calculation Reference Table The following table shows an example of the frequency calculation reference table when the data collection sampling frequency is 4000 Hz and the rated frequency is 50 Hz. In the table, the display of data with a gauge rotation phase angle smaller than 90 ° is omitted. The conversion calculation of these data is the same as in the first row. As shown in the table, even if the actual frequency of the power system fluctuates, an accurate gauge rotation phase angle corresponding to each scale can be obtained by referring to the frequency calculation reference table.

  For reference, the following table shows an example of a frequency calculation reference table when the data collection sampling frequency is 4000 Hz and the rated frequency is 60 Hz.

(X) Physical meaning of the multi-scale method The time waveform to be measured includes various harmonic components in addition to the fundamental component. An equivalent measurement frequency _{fe that} is a frequency obtained as a result of the measurement using symmetry is expressed as shown in the following equation (37).

Here, f is the fundamental frequency, f _k is a frequency indicating an unspecified number of harmonic components existing in the actual power system, and f _noise is additive Gaussian noise in the measurement. When the scale is small (ie, the sampling frequency is large or the number of gauge sampling points is small), the gauge rotation phase angle becomes small, and the combined value of an unspecified number of harmonic components has a greater influence than the fundamental frequency. become. In this case, the following equation (38) is established.

As shown in the equation (38), the equivalent measurement frequency _fe becomes higher than the fundamental frequency only by the influence of additive Gaussian noise. For example, when a power system simulator is used, the equivalent measurement frequency _fe is calculated to be larger than the fundamental frequency f even though there are no unspecified number of harmonic components that should exist in the actual power system. Furthermore, when an unspecified number of harmonic components are added in an actual power system, the equivalent measurement frequency _fe is calculated to be larger.

On the other hand, when the scale is large (that is, the sampling frequency is small or the number of gauge sampling points is large), the gauge rotation phase angle is large, and the influence of additive Gaussian noise is small. Here, by using the frequency calculation reference table, the gauge rotation phase angle that can be used for calculation is expanded to 360 ° or more. In this case, the following equation (39) is established. Furthermore, when the number of gauge sampling points is large, the combined values of an unspecified number of harmonic components cancel each other, and the following equation (40) is established. As a result, as shown in the following equation (41), the equivalent measurement frequency _fe is substantially equal to the fundamental frequency f.

  In other words, in the multiscale method of the present embodiment, by using the frequency calculation reference table and expanding the gauge rotation phase angle that can be used for calculation to 360 ° or more, an unspecified number of harmonic components and additive Gaussian noise are obtained. The measurement accuracy of the fundamental frequency can be improved.

(Xi) About the physical meaning of the isolated operation discrimination algorithm from the power system When connected to the actual power system, a large number of unspecified harmonic components exist in the large-scale power system. The equivalent measurement frequency _fe is calculated according to the above equation (37).

On the other hand, when isolated and operating independently from the power system, there is no electrical connection with a large-scale power system, and there are no unspecified number of harmonic components from there. The equivalent measurement frequency _fe is a smaller value as shown in the following equation (42).

That is, when the measured value of the equivalent measurement frequency _fe obtained from the power system that is always operating is greatly reduced from the normal value, it can be determined that the system is in a single operation state disconnected from the system power source.

(Xii) Measurement of unspecified fundamental wave As described above, the frequency calculation reference table for measuring the actual frequency of the power system has been described. When the power system is in steady operation, the actual frequency of the power system remains within a few Hz centered on the system rated frequency. It is possible to measure with high accuracy.

  However, when the generator is activated, the frequency of the generator is accelerated from 0 to the system rated frequency, and when the generator is stopped, the frequency of the generator is decelerated from the system rated frequency to 0.

  In general signal processing, various fundamental wave components exist in the signal to be measured, and these fundamental waves also change. In order to cope with these situations, a plurality of frequency calculation reference tables are prepared in advance, and when the fundamental wave is changing, the current frequency calculation reference table, the frequency calculation reference table of the higher fundamental frequency, Calculate the fundamental measurement value using the frequency calculation reference table so that the three fundamental frequency calculation reference tables for the lower fundamental wave are calculated simultaneously and the corresponding fundamental measurement value converges to a different scale. adopt. In the subsequent processing, the adopted frequency calculation reference table is used as an intermediate frequency calculation reference table, and at the same time, the fundamental wave measurement is performed using a total of three frequency calculation reference tables including two frequency calculation reference tables before and after. By taking such a procedure into consideration, it is possible to move the frequency calculation reference table, thereby responding to changes in the fundamental wave.

  As described above, in the present embodiment, by referring to the conversion factor that is prepared in advance for each of the plurality of fundamental wave frequencies and that is determined in advance for each of the gauge sampling frequencies, it is directed to the measurement object whose frequency changes. A conversion factor is calculated.

(Xiii) Current Fundamental Frequency Estimation Method According to the above-described multiple scale of the present embodiment, the larger the scale, the lower the influence of harmonic components and the higher the fundamental frequency measurement accuracy. it can. However, when the fundamental frequency is changing at a high speed, if the measurement is performed on a large scale, the measurement time is delayed. In such a case, the current fundamental frequency may be estimated by the following method.

FIG. 16 is a diagram for explaining a method of estimating the fundamental frequency at the present time. Referring to FIG. 16, the fundamental frequency f _T at the present moment can be calculated according to the following expression (43).

However, f _T is the estimated fundamental wave frequency at the present time, and f _M and f _N are the fundamental wave frequency measured at the present time with the number of gauge sampling points N _g = M, and the gauge wave before the _TN time point, respectively. This is the fundamental frequency measured with the number of sampling points N _g = N. Further, T ₀₁ and T ₁₂ are time delays in measurement at each gauge sampling point (scale), and the proportional value is calculated according to the following equation (44).

Where α _M and α _N are gauge rotation phase angles corresponding to the gauge sampling points N _g = M and N _g = N, respectively.

As shown in FIG. 16, the time delay from the original fundamental frequency of frequency (measurement frequency) to be measured in certain gauge number of sampling points N _g (theoretical frequency), proportional to the magnitude of the gauge number of sampling points N _g (number) Then you can think. Therefore, as shown in the above-mentioned (43) and (44) below, using the measured frequency in a plurality of gauges sampling points N _g, it is possible to estimate the fundamental frequency at the moment.

  That is, first and second instantaneous frequencies (measured fundamental wave frequencies) respectively corresponding to the first and second gauge sampling frequencies (the number of gauge sampling points or scale) are calculated. Based on the first and second instantaneous frequencies obtained by calculation and the first and second gauge rotation phase angles corresponding to the first and second gauge sampling frequencies, respectively, The wave frequency is estimated.

  Further, referring to FIG. 16, the change rate of the fundamental frequency is calculated according to the following equation (45).

(D4: Modification)
In the above description, the technique disclosed in the above-mentioned Patent Document 1 is applied to generate the frequency calculation reference table using the gauge voltage group and the gauge differential voltage group, but other techniques are employed. May be.

  For example, a frequency calculation reference table may be generated using a gauge synchronous phasor group and a gauge differential synchronized phasor group (see Embodiment 2). Moreover, you may produce | generate a frequency calculation reference table using a gauge power group or a gauge difference power group (refer Embodiment 3). Further, a frequency calculation reference table may be generated using the gauge dual voltage group and the gauge differential dual voltage group (see Embodiment 4).

  In the following description, using an example of an actual waveform, first, frequency components are analyzed using FFT, and then measurement is performed by a multiscale method to prove its effectiveness.

[E. Embodiment 1]
In the first embodiment, a configuration for measuring various electric quantities using the above-described gauge voltage group and gauge differential voltage group will be described.

(E1: Device configuration)
In the following description, a signal having a function of measuring the frequency of the power system, a function of measuring the voltage amplitude of the power system, and a configuration for determining whether or not the system is in a single operation state using the above-described multiscale method. The processing apparatus 100 will be described as an example. For convenience of explanation, the configuration in which the signal processing apparatus 100 provides all the functions described above is illustrated. However, necessary functions are selected or distributed to different processing apparatuses according to application destinations and uses. Can also be implemented.

  FIG. 17 is a schematic diagram illustrating a configuration example of the signal processing device 100 according to the first embodiment. Referring to FIG. 17, signal processing apparatus 100 has, as its functional configuration, voltage instantaneous value data input unit 101, frequency coefficient calculation unit 102, symmetry breaking determination unit 103, power failure / failure handling unit 104, Average frequency coefficient calculation unit 105, gauge rotation phase angle calculation unit 106, gauge rotation phase angle averaging unit 107, instantaneous frequency calculation unit 108, instantaneous frequency averaging unit 109, isolated operation determination unit 110, basic Wave frequency selection unit 111, gauge difference voltage calculation unit 112, gauge difference voltage averaging unit 113, AC voltage amplitude calculation unit 114, DC component calculation unit 115, communication unit 116, storage unit 117, and interface 118.

  These functions are realized by known hardware and software. Specifically, all or part of the functions shown in FIG. 17 may be realized using LSI (Large Scale Integration) or the like, or in addition to or instead of a CPU (Central Processing Unit) or the like. You may implement | achieve by running a program with a processor. Further, it can be implemented as a single device, or a configuration that realizes the function shown in FIG. 17 as a whole by linking a plurality of devices via a network or the like can be employed. Furthermore, the signal processing apparatus 100 shown in FIG. 17 can be implemented as a partial function of a larger apparatus (for example, a power monitoring apparatus). How to implement the signal processing apparatus 100 shown in FIG. 17 is appropriately designed according to the application destination.

  The communication unit 116 provides a function for exchanging data with another signal processing apparatus 100 or another apparatus. The storage unit 117 stores measurement data, calculation information, and the like. The interface 118 has an interface function such as digital display. The other functions of FIG. 17 will be described together in the description of the processing procedure shown in FIG.

(E2: Processing procedure)
Next, a processing procedure executed by the signal processing device 100 shown in FIG. 17 will be described. FIG. 18 is a flowchart illustrating a processing procedure executed by the signal processing apparatus 100 according to the first embodiment. Each step shown in FIG. 18 is typically executed in the configuration shown in FIG.

  Referring to FIG. 18, instantaneous voltage value data input unit 101 acquires an instantaneous voltage value from a voltage transformer (PT) provided in the power system (step S101). That is, the voltage instantaneous value data input unit 101 collects instantaneous value data in time series by sampling the measurement target at the collection sampling frequency. The read voltage instantaneous value data is sequentially stored in the storage unit 117 in time series.

  Subsequently, the frequency coefficient calculation unit 102 calculates a plurality of instantaneous values of frequency coefficients from the instantaneous voltage values acquired in time series (step S102). The calculated frequency coefficient is an instantaneous frequency coefficient of a plurality of gauge differential voltage groups, and is calculated according to the following equation (46).

_{However, v 21, v 22, v} 23 is the three differential voltage instantaneous value of the gauge differential voltage group corresponding to _{N g} respectively.

  Subsequently, the symmetry breaking determination unit 103 determines whether or not the symmetry of the plurality of gauge differential voltage groups is broken (step S103). That is, the symmetry breaking determination unit 103 determines whether or not the measured electric quantity has a symmetry group characteristic. Whether or not this symmetry is broken is determined according to the following equation (47).

When each of the gauge difference voltage groups satisfies the above-described expression (47), it can be determined that the symmetry of the gauge difference voltage group is broken. That is, the symmetry corresponding to each of the plurality of gauge sampling frequencies f _g is maintained by using the instantaneous value data of the four points constituting the symmetry group while being temporally continuous at the sampling interval at the collection sampling frequency. Each of them is determined.

For any gauge number of sampling points N _g, in a case where symmetry of the gauge differential voltage group is determined to be torn (YES in step S103), the process of step S104 is executed. In contrast, if the symmetry of the gauge differential voltage group for any gauge sampling points N _g is determined not torn (NO in step S103), the process of step S104 is skipped.

The frequency coefficient f _C of the symmetry group with respect to the number of gauge sampling points N _g determined to be broken is not calculated in the current step, but is latched in order to use the determined value of the previous step (step S104). ). For some of the gauge number of sampling points N _g, if the symmetry of the symmetric group is broken, because the cause is thought to influence of voltage flickering, the frequency coefficients f _C before steps for these symmetric group Use a fixed value. That is, as shown in the following equation (48), a definite value that is only before time T ₁ is used.

f _C (t) = f _C (t−T ₁ ) (48)
Note that a plurality of gauges sampling points N _g, if the symmetry of the gauge differential voltage group is determined to have lost at the same time, it can be determined with the disturbance such as an accident in the power system has occurred, to reduce the influence of disturbance You may perform the process for.

  That is, the symmetry breaking determination unit 103 determines a state occurring in the measurement target according to the number of gauge sampling frequencies determined to have no symmetry maintained among a plurality of gauge sampling frequencies.

  For example, the power failure / fault handling unit 104 may activate a process for reducing the influence of a power failure or a failure at a high speed. For example, when the signal processing apparatus 100 is applied to a UPS (Uninterruptible Power Supply) apparatus, the standby power supply is immediately turned on. Further, when the signal processing device 100 is applied to a protective relay device, relay main calculation is performed to protect the system.

Subsequently, the average frequency coefficient calculation unit 105 calculates an average value of the frequency coefficients f _C for each of the gauge differential voltage groups (step S105). Typically, the average frequency coefficient calculation unit 105 performs a moving average process on the frequency coefficient f _C for each of the plurality of gauge sampling points N _g according to the following equation (49).

  However, M in the equation (49) is the number of data collection sampling points including the current step. The average frequency coefficient calculation unit 105 averages the instantaneous frequency by moving average processing.

Subsequently, the gauge rotation phase angle calculator 106 calculates the gauge rotation phase angle α _g (N _g ) corresponding to each of the plurality of scales (N _g ) (step S106). The gauge rotation phase angle calculation unit 106 calculates a gauge rotation phase angle corresponding to each of a plurality of gauge sampling frequencies. The gauge rotation phase angle α _g (N _g ) is calculated according to the following equation (50). In calculating the gauge rotation phase angle α _g (N _g ) of each scale, a necessary value is calculated with reference to a frequency calculation reference table generated in advance.

Subsequently, the gauge rotation phase angle averaging unit 107 calculates an average value of the gauge rotation phase angles α _g (N _g ) respectively corresponding to the plurality of scales (step S107). Typically, the gauge rotation phase angle averaging unit 107 performs a moving average process on the gauge rotation phase angle α _g (N _g ) for each of the plurality of scales according to the following equation (51).

However, M in the equation (51) is the number of data collection sampling points including the current step.
Subsequently, the instantaneous frequency calculation unit 108 calculates the instantaneous frequency f (N _g ) corresponding to each of the plurality of scales (step S108). The instantaneous frequency f (N _g ) is calculated according to the following equation (52).

Where f _g is the gauge sampling frequency. As shown in the equation (52), the instantaneous frequency calculation unit 108 corresponds to each of the plurality of gauge sampling frequencies based on each of the plurality of gauge sampling frequencies and the gauge rotation phase angle for each gauge sampling frequency. Each instantaneous frequency is calculated.

Subsequently, the instantaneous frequency averaging unit 109 calculates an average value of the instantaneous frequencies f (N _g ) corresponding to the plurality of scales (step S109). Typically, the instantaneous frequency averaging unit 109 performs a moving average process on the instantaneous frequency f (N _g ) for each of the plurality of scales according to the following equation (53).

However, M in the equation (53) is the number of data collection sampling points including the current step.
Subsequently, the isolated operation determination unit 110 determines whether or not the operation is isolated from the system power supply based on the harmonic components corresponding to the plurality of scales (step S110). Specifically, the isolated operation determination unit 110 determines whether or not the following expression (54) is satisfied.

However, f _hSET [N _g ] is a preset threshold value. When the equation (54) is satisfied at the selected scale, that is, when the average value of the instantaneous frequency is below the threshold value, the harmonic component of the actual voltage waveform / actual current waveform of the power system is It can be determined that it is rapidly decreasing, and the isolated operation determination unit 110 can determine that the power system is in an isolated operation state. That is, the isolated operation determination unit 110 detects a change in state of the measurement target based on a change in average value of instantaneous frequencies corresponding to a relatively high gauge sampling frequency among a plurality of gauge sampling frequencies.

  For example, in a system with a data collection sampling frequency of 4000 Hz and a rated frequency of 50 Hz, the following two scales are selected, and the threshold values shown in the following equation (55) are respectively set.

In this case, when the average frequency of N _g = 1 and N _g = 2 (the average value of the instantaneous frequency f (N _g )) is simultaneously below 200 Hz and 100 Hz, respectively, the harmonic components of the power system rapidly decrease, It can be determined that it has become an independent operation.

  When actually setting the threshold values for each scale, it is considered necessary to investigate and measure the presence of harmonic components in the load in the voltage class of the symmetric power system.

Subsequently, the fundamental frequency selection unit 111 selects a fundamental frequency (step S111). The fundamental frequency selection unit 111 selects an average frequency (average value of the instantaneous frequency f (N _g )) corresponding to an appropriate number of gauge sampling points N _g, and outputs it as a measurement result of the fundamental frequency.

Subsequently, the gauge difference voltage calculation unit 112 calculates a gauge difference voltage V _gd corresponding to the gauge sampling number N _g selected in advance (step S112). More specifically, the gauge differential voltage V _gd is calculated according to the following equation (56).

Subsequently, the gauge difference voltage averaging unit 113 calculates the average value of the gauge difference voltage V _gd calculated in step S112 (step S113). Typically, the gauge difference voltage averaging unit 113 performs a moving average process on the gauge difference voltage V _gd .

  Subsequently, the AC voltage amplitude calculation unit 114 calculates the AC voltage amplitude V (step S114). The AC voltage amplitude V is calculated according to the following equation (57).

Gauge sampling points N _g that generally (57) corresponding to the frequency coefficient f _C in the formula is greater than the gauge number of sampling points N _g for calculating the AC voltage amplitude.

Subsequently, the DC component calculation unit 115 calculates the DC component V _DC (step S115). The direct current component V _DC is calculated according to the above equation (24).

  Finally, each value calculated by the above-described procedure is output as a measurement result (step S116). For example, it is used as the actual frequency of a frequency relay or power system state monitoring point. Then, it is determined whether or not termination is instructed (step S117). If termination is not instructed (NO in step S117), the processing in step S101 and subsequent steps is repeatedly executed. If termination is instructed (YES in step S117), the series of processing ends.

(E3: Evaluation of usefulness)
Hereinafter, the results of evaluating the usefulness of the multiscale method of the first embodiment by comparison with simulation and actual measurement values according to the apparatus configuration shown in FIG. 17 and the processing procedure shown in FIG. 18 will be described.

(E3-1: Case 1: Fundamental wave simulation)
First, assuming a fundamental wave that does not include a certain harmonic component, the results of evaluation by simulation that the multiscale method of the first embodiment can appropriately measure the fundamental wave are shown below.

  The parameters used for the fundamental wave simulation of Case 1 are shown in the following table.

  The frequency calculation reference table used for the fundamental wave simulation of Case 1 is shown below. This frequency calculation reference table is calculated in advance.

  First, according to the parameters of case 1, the input waveform is defined according to the following equation (58).

  The simulation results of AC voltage amplitude and instantaneous frequency measurement are shown in FIGS. 19 and 20, respectively. FIG. 19 is a diagram illustrating simulation results for the instantaneous voltage value and the effective voltage value in the fundamental wave simulation of Case 1. FIG. FIG. 20 is a diagram illustrating a simulation result of an instantaneous frequency in the fundamental wave simulation of case 1.

As shown in FIG. 19, even if the scales are different, the fundamental wave that does not include harmonic components is completely symmetric. Therefore, in any case of the number of gauge sampling points N _g = 20, 140, 260, the input waveform It agrees with the sine wave amplitude, and the same measurement result is obtained for the AC voltage amplitude. That is, in the fundamental wave (no harmonics) measurement, the measurement result of the instantaneous frequency by all the plurality of gauge sampling frequencies is the same. This measurement result (simulation result) proves that the proposed method has symmetry and the logic of the multiscale method is correct, like the single-scale method of the prior application.

Further, as shown in FIG. 20, even if the scales are different, the fundamental wave that does not include the harmonic component is completely symmetric. Therefore, in any case of the number of gauge sampling points N _g = 20, 140, 260, the input The same measurement result is obtained for the instantaneous frequency. This measurement result (simulation result) also proves that the logic of the multi-scale method is correct.

(E3-2: Case 2: Comparison with measured values)
As Case 2, the usefulness of the multiscale method of Embodiment 1 is evaluated using a time waveform measured from an actual power system.

  The parameters of the signal processing device 100 used for comparison with the actual measurement values of Case 2 are shown in the following table.

  In addition, a frequency calculation reference table used for comparison with the actual measurement value of Case 2 is shown below. This frequency calculation reference table is calculated in advance.

The results of comparison with the actual measurement values of Case 2 are shown in FIGS.
FIG. 21 is a diagram illustrating a time waveform of the observed voltage in the actual measurement example of case 2. In FIG. The recorded data measured from the actual power system is for 3 seconds, but for convenience of explanation, the time scale is expanded to display only data for 0.2 seconds. FIG. 21 seems to show a clean sine wave consisting only of the fundamental wave at first glance, but it can be confirmed that various harmonic components are actually included.

  FIG. 22 is a diagram illustrating a spectrum calculation result obtained by performing FFT on the time waveform of the observed voltage in the actual measurement example of case 2. FIG. FIG. 22 shows a spectrum calculation result obtained by performing FFT using all the measured data for 3 seconds in order to confirm the harmonic component. As shown in FIG. 22, it can be confirmed that a fundamental wave appears at 60 Hz, and a peak due to an aliasing phenomenon having the same intensity as that of the fundamental wave appears at 3940 Hz (= 4000 Hz-60 Hz).

  FIG. 23 is an enlarged view showing the range of 0 to 840 [Hz] of the spectrum shown in FIG. FIG. 24 is an enlarged view showing the range of 0 to 420 [Hz] of the spectrum shown in FIG.

  Referring to FIG. 23 in which the display scale of the spectrum calculation result shown in FIG. 22 is enlarged, the magnitudes of the harmonics are the fifth harmonic (300 Hz = 5 × 60 Hz), the interharmonic harmonic (109 Hz), and the seventh order. It can be seen that the order of the harmonics (420 Hz = 7 × 60 Hz) and the 13th harmonic (780 Hz = 13 × 60 Hz) are in order.

  Referring to FIG. 24, it can be seen that many types of frequency components are included. Note that the third harmonic (180 Hz = 3 × 60 Hz) has a small intensity because it generally cancels each other out in the Δ winding (delta connection) of the transformer, and is blocked from the power source (power plant). This is because it does not flow out to the (electric power system).

25 to 34 show the instantaneous frequency measurement results at each scale. FIG. 25 is a diagram illustrating the measurement result of the instantaneous frequency when the number of gauge sampling points N _g = 1 in the actual measurement example of case 2. FIG. 26 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 2 in the actual measurement example of case 2. FIG. 27 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 3 in the actual measurement example of case 2. FIG. FIG. 28 is a diagram showing the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 12 in the actual measurement example of Case 2. FIG. 29 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 17 in the actual measurement example of case 2. FIG. FIG. 30 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 117 in the actual measurement example of case 2. FIG. 31 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 217 in the actual measurement example of case 2. FIG. FIG. 32 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 317 in the actual measurement example of case 2. FIG. 33 is a diagram illustrating the measurement result of the instantaneous frequency at the number of gauge sampling points N _g = 417 in the actual measurement example of case 2. FIG. FIG. 34 is a diagram showing the measurement result of the instantaneous frequency when the number of gauge sampling points N _g = 983 in the actual measurement example of case 2.

  As shown in FIGS. 25 to 34, it is proved that the multiscale method of the first embodiment can be applied to an actual voltage waveform / an actual current waveform including an unspecified number of harmonic components.

The table below shows the maximum and minimum values of the measurement results of the instantaneous frequencies corresponding to each of the gauge number of sampling points N _g. Furthermore, in order to intuitively display the maximum value and the minimum value of the measurement results shown in the following table, FIG. 35 and FIG. 36 show distribution curves of instantaneous frequencies at respective gauge sampling points and their enlarged views.

  FIG. 35 is a diagram showing a distribution curve of instantaneous frequency at each gauge sampling point in the actual measurement example of case 2. FIG. FIG. 36 shows an enlarged view of the instantaneous frequency distribution curve shown in FIG.

According to the measurement results shown in FIGS. 25 to 36, when the number of gauge sampling points _Ng is small, most of the measured value of the instantaneous frequency is larger than the fundamental frequency. Therefore, it can be seen that the average frequency, which is the average value of the instantaneous frequency, is also larger than the measured value of the fundamental frequency and is asymmetric with respect to the fundamental frequency. It is shown in FIGS. Please refer to the section showing the asymmetry of the distribution curve of the instantaneous frequency.

According to the measurement results shown in FIG. 25 to FIG. 36, if the number of gauge sampling points _Ng is equal to or greater than a certain value, the measured value of the instantaneous frequency is symmetric and normal with respect to the measured value of the fundamental frequency. ing. If averaging processing (for example, moving average processing) is performed on the measurement value of the instantaneous frequency, a stable measurement value of the fundamental frequency can be obtained. For example, the actual waveform of the power system is composed of a fundamental wave and a plurality of unspecified harmonic components. According to the instantaneous frequency distribution curve of the power system based on the multi-scale method, the instantaneous frequency measurement value is larger than the fundamental wave at a small scale (that is, when the gauge sampling point number _Ng is small and the gauge sampling frequency _fg is large). Therefore, it is preferable that the plurality of gauge sampling frequencies be set according to the ratio of the fundamental wave component and the harmonic component included in the measurement target.

In general, the gauge number of sampling points N _g is large, the difference between the maximum value and the minimum value is reduced, thus, it is possible to reduce the influence of harmonic components. It is shown in FIGS. Please refer to the part showing the symmetry of the distribution curve of the instantaneous frequency.

  However, when the scale is very large (that is, the gauge sampling frequency is very small), the function of reducing the influence of the harmonic component is saturated, and the influence of the harmonic component cannot be further reduced. According to the uncertainty principle of quantum mechanics, even if the scale is increased, a complete sine wave in which the influence of the harmonic component is zero cannot be obtained. Furthermore, if the scale is too large, the measurement time becomes longer, which is disadvantageous for system control protection. Therefore, it is preferable to select an appropriate scale.

  From the measurement results as described above, the multiscale method of the first embodiment can be applied as follows.

(I) Application of harmonic component measurement The harmonic component measurement of the first embodiment can be applied to discriminating system independent operation.

FIG. 37 is a diagram showing the measurement result of the average frequency at the number of gauge sampling points N _g = 1, 2, 3, 12 in the measurement example of Case 2. As shown in FIG. 37, in general, a large-scale power system interconnected by alternating current of the same rated frequency includes a large number of unspecified harmonic components. Wave components are considerably reduced. If the average frequency measured on a small scale is rapidly reduced by utilizing such a feature, the harmonic component of the actual voltage waveform / actual current waveform is rapidly decreased. Therefore, the electric station at the observation point determines that the system to be observed is disconnected from the large-scale power system connected to the interconnection destination, and performs control related to the single operation. In this way, the troublesome phenomenon that a plurality of harmonic components of a large-scale power system is present can be taken over, and an inexpensive and highly accurate isolated operation determination device can be realized.

(Ii) Application of Stable Fundamental Wave Measurement FIG. 38 is a diagram showing the measurement results of the average frequency at the number of gauge sampling points N _g = 17,117 in the actual measurement example of Case 2. In the measurement waveform of the average frequency at the number of gauge sampling points N _g = 17, pulse-like changes (up and down) are caused by voltage flicker (that is, sudden phase change due to load change). From the measurement results shown in FIG. 38, it can be seen that the multiscale method of the first embodiment has a high time resolution.

Further, according to the measurement waveform at the number of gauge sampling points N _g = 117, it can be understood that the influence of voltage flicker is greatly reduced and the fundamental frequency can be stably measured by increasing the scale.

(Iii) Application of Voltage Amplitude Measurement FIG. 39 is a diagram showing the measurement result of voltage amplitude at the number of gauge sampling points N _g = 17 in the actual measurement example of Case 2. The measurement result shown in FIG. 39 is the result of measuring the voltage amplitude using the frequency coefficient obtained at N _g = 117 and the gauge differential voltage group obtained at N _g = 17. For convenience of explanation, in FIG. 39, the scale of the axial time is greatly expanded. In this way, high-speed and high-precision voltage amplitude measurement can be realized online.

(Iv) Application of DC Component Measurement FIG. 40 is a diagram showing a DC component measurement result at the number of gauge sampling points N _g = 17 in the actual measurement example of Case 2. FIG. 40 shows the measurement result of the DC component by the multiscale method of the first embodiment. As can be seen from FIG. 40, the measurement result of the DC component with high time resolution is obtained.

  Note that the measured DC component does not exist in the power system but may be a DC offset of the measuring device. Therefore, the average value of the DC component can be used for AI correction of the measuring device (DC offset gain setting adjustment of the measuring device). In general AI correction, it is necessary to input a sine wave from a high-precision measuring device. However, as shown in FIG. 40, a direct current component using an actual voltage waveform / an actual current waveform including various harmonic components is used. Can be measured with high accuracy, and high-precision measuring equipment can be manufactured at low cost.

  For example, if a multi-scale method is applied to a digital control protection device and all frequency components (input data is used as they are) are measured simultaneously, the filter device used as a pre-processing of the input waveform can be eliminated. As a result, when compared with a digital control protection device required by a filter that cuts off current harmonics, a lower cost can be realized.

[F. Second Embodiment]
As the second embodiment, the above-described multiscale method is applied, and the gauge synchronous phasor group or the gauge differential synchronous phasor group proposed in Japanese Patent Application No. 2013-008598 already filed by the present inventor is used. A method for measuring the synchronized phasor will be described.

  As an application example thereof, a synchronous phasor measurement device (PMU: Phase Measurement Unit) will be described. Synchronous phasor measurement devices are one of the most important devices in smart grids where research and development are actively conducted. We propose a new synchronous phasor measurement device based on group theory, unlike the device based on conventional FFT theory.

  The advancement compared to the method disclosed in Japanese Patent Application No. 2013-008598 is the introduction of the multi-scale method, and along with this, the gauge rotation phase angle is used instead of the rotation phase angle. .

  Hereinafter, first, the gauge synchronized phasor group and the gauge differential synchronized phasor group will be described, and then the apparatus configuration and processing procedure of the synchronized phasor measuring apparatus will be described. Finally, a comparison example between the fundamental wave simulation and the actually measured value will be described.

(F1: Gauge synchronized phasor group)
FIG. 41 is a diagram illustrating a gauge synchronous phasor group on a complex plane. Referring to FIG. 41, three voltage rotation vectors on the complex plane are defined according to the following equation (59).

Where V is the AC voltage amplitude, ω is the rotational angular velocity, T _g is the gauge sampling period, α _g is the gauge rotational phase angle at T _g , and φ is the synchronized phasor phase angle. The three voltage rotation vectors shown in the equation (59) are a gauge voltage group.

  Assume that three unit vectors fixed on the complex plane are expressed according to the following equation (60).

  The above-mentioned gauge voltage group and three unit vectors are combined to form a gauge synchronous phasor group. Similar to the technique disclosed in Japanese Patent Application No. 2013-008598, a vector group table of the gauge-synchronized phasor group can be created and the symmetry of the gauge-synchronized phasor group can be considered.

  The real part instantaneous value of the voltage rotation vector of the gauge voltage group shown in FIG. 41 is calculated according to the following equation (61), and the real part instantaneous value of the three unit vectors is calculated according to the following equation (62). .

  Re in the above equations (61) and (62) represents the real part of the complex number. The real number group table of the gauge synchronous phasor group is shown in the following table.

Using this real group table, various invariants of the gauge synchronous phasor group can be calculated. As a typical example of such an invariant, a frequency coefficient is shown below. The frequency coefficient f _C of the gauge synchronous phasor group is calculated according to the equation (63). Thus, the symmetry breaking index of the gauge synchronous phasor group can be set as shown in Equation (64).

  Since the synchronized phasor phase angle is constantly changing, if the symmetry is broken, the result of the synchronized phasor measurement of another scale is used.

  The gauge effective synchronization phasor is calculated according to the following equation (65), and the gauge invalid synchronization phasor is calculated according to the following equation (66).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table.
The real part and imaginary part of the voltage rotation vector are calculated according to the following equation (67).

  From the above equation (67), the synchronized phasor phase angle is calculated according to the following equation (68).

(F2: Gauge differential synchronized phasor group)
FIG. 42 is a diagram illustrating a gauge differential synchronized phasor group on a complex plane. Referring to FIG. 42, three differential voltage rotation vectors on the complex plane are defined according to the following equation (69).

Where V is the AC voltage amplitude, T _g is the gauge sampling period, α _g is the gauge rotation phase angle at T _g , and φ is the synchronized phasor phase angle. The three voltage rotation vectors shown in the equation (69) are a gauge differential voltage group.

  Assume that three difference unit vectors fixed on the complex plane are expressed according to the following equation (70).

  The above-described gauge difference voltage group and three difference unit vectors are combined to form a gauge difference synchronized phasor group. Similar to the technique disclosed in Japanese Patent Application No. 2013-008598, a vector group table of the gauge differential synchronized phasor group can be created and the symmetry of the gauge differential synchronized phasor group can be considered. Details are omitted.

  The real part instantaneous value of the differential voltage rotation vector of the gauge differential voltage group shown in FIG. 42 is calculated according to the following equation (71), and the real part instantaneous value of the three difference unit vectors is according to the following equation (72). Calculated.

  Re in the above equations (71) and (72) represents the real part of the complex number. The real number group table of the gauge differential synchronized phasor group is shown in the following table.

Using this real group table, various invariants of the gauge differential synchronized phasor group can be calculated. As a typical example of such an invariant, a frequency coefficient is shown below. The frequency coefficient f _C of the gauge difference synchronized phasor group is calculated according to the equation (73). Thus, the symmetry breaking index of the gauge differential synchronization phasor group can be set as shown in the equation (74).

  The gauge difference effective synchronization phasor is calculated according to the following equation (75), and the gauge difference invalid synchronization phasor is calculated according to the following equation (76).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table.
The real part and imaginary part of the differential voltage rotation vector are calculated according to the following equation (77). From the equation (77), the synchronized phasor phase angle is calculated according to the following equation (78).

  As described above, it can be seen that the gauge differential synchronized phasor group is a structure having the same symmetry as the gauge synchronized phasor group.

(F3: Device configuration)
FIG. 43 is a schematic diagram illustrating a configuration example of the synchronized phasor measuring device 200 according to the second embodiment. Referring to FIG. 43, synchronous phasor measuring apparatus 200 has, as its functional configuration, voltage instantaneous value data input unit 201, average frequency calculation unit 202, fundamental frequency coefficient selection unit 203, and AC voltage amplitude calculation unit 204. A difference unit vector group generation unit 205, a symmetry breaking determination unit 206, a gauge difference effective synchronization phasor calculation unit 207, a gauge difference invalid synchronization phasor calculation unit 208, a synchronization phasor phase angle calculation unit 209, and a synchronization phasor. The phase angle selection unit 210, the time synchronization phasor calculation unit 211, the synchronization phasor reception unit 212, the space synchronization phasor calculation unit 213, the storage unit 214, and the interface 215 are included.

  These functions are realized by known hardware and software. Specifically, all or part of the functions shown in FIG. 43 may be realized using an LSI or the like, or in addition to or instead of being executed by causing a processor such as a CPU to execute a program. May be. Further, it can be implemented as a single device, or a configuration that realizes the function shown in FIG. 43 as a whole by linking a plurality of devices via a network or the like can be adopted. Furthermore, the synchronized phasor measuring device 200 shown in FIG. 43 can be implemented as a partial function of a larger device (for example, a power monitoring device). How to implement the synchronized phasor measuring device 200 shown in FIG. 43 is appropriately designed according to the application destination.

  The storage unit 214 stores measurement data, calculation information, and the like. The interface 215 has an interface function such as digital display. The other functions of FIG. 43 will be described together in the description of the processing procedure shown in FIG. 44 described later.

(F4: Processing procedure)
Next, a processing procedure executed by the synchronized phasor measuring device 200 shown in FIG. 43 will be described. FIG. 44 is a flowchart illustrating a processing procedure executed by the synchronized phasor measuring device 200 according to the second embodiment. Each step shown in FIG. 43 is typically executed in the configuration shown in FIG.

  Referring to FIG. 43, instantaneous voltage value data input unit 201 acquires an instantaneous voltage value from a voltage transformer (PT) provided in the power system (step S201). The read voltage instantaneous value data is sequentially stored in the storage unit 214 in time series.

  Subsequently, the average frequency calculation unit 202 calculates an average value of instantaneous frequencies for each of the gauge difference voltage groups corresponding to the plurality of scales (step S202). Typically, the average frequency calculation unit 202 performs a moving average process for each of a plurality of instantaneous frequencies.

  Subsequently, the fundamental frequency coefficient selection unit 203 selects a fundamental frequency coefficient (step S203). The fundamental frequency coefficient selection unit 203 selects a stable fundamental frequency coefficient having an appropriate scale from the calculation results of the fundamental frequency coefficients respectively corresponding to a plurality of scales. That is, the fundamental frequency coefficient selection unit 203 applies the conversion coefficient for the stable second gauge sampling frequency to the unstable first gauge sampling frequency among the plurality of gauge sampling frequencies.

  Subsequently, the AC voltage amplitude calculation unit 204 calculates the AC voltage amplitude from the selected gauge differential voltage group using the selected fundamental frequency coefficient (step S204).

  Subsequently, the difference unit vector group generation unit 205 generates a difference unit vector group corresponding to each of a plurality of scales (step S205). The difference unit vector group generation unit 205 generates difference unit vector groups respectively corresponding to a plurality of scales based on the gauge rotation phase angle based on the selected fundamental frequency coefficient.

  Subsequently, the symmetry breaking determination unit 206 determines whether or not the symmetry of the synchronized phasor group corresponding to each of the plurality of scales is broken (step S206). Whether or not this symmetry is broken is determined using the symmetry breaking index of the gauge synchronous phasor group shown in the above equation (74).

  Subsequently, the gauge difference effective synchronization phasor calculation unit 207 configures a gauge difference synchronization phasor group corresponding to each of a plurality of scales, and calculates a gauge difference effective synchronization phasor (step S207).

  Subsequently, the gauge difference invalid synchronization phasor calculation unit 208 calculates a gauge difference invalid synchronization phasor from the gauge difference synchronization phasor groups respectively corresponding to the plurality of scales constructed previously (step S208).

  Subsequently, the synchronized phasor phase angle calculation unit 209 calculates a synchronized phasor phase angle corresponding to each of a plurality of scales (step S209). Further, the synchronized phasor phase angle selection unit 210 selects a synchronized phasor phase angle (step S210). Since the synchronized phasor phase angle is constantly changing, it is difficult to latch the synchronized phasor phase angle when symmetry breaking occurs. Therefore, the measured value of the synchronized phasor phase angle of another scale is used.

  Subsequently, the time synchronization phasor calculation unit 211 calculates a time synchronization phasor (step S211). The time synchronization phasor is calculated according to the following equation (79).

However, T ₀ is the specified time step size (e.g., power system nominal frequency 1 cycle time). Thus, a time-synchronized phasor is defined as a synchronized phasor phase angle difference in different time sections of the same node.

  Subsequently, the synchronized phasor receiving unit 212 receives a synchronized phasor from another synchronized phasor measuring apparatus 200 (step S212). The synchronized phasor receiving unit 212 receives a synchronized phasor phase angle and time information (for example, GPS time stamp) from another synchronized phasor measuring device 200 in order to calculate a spatially synchronized phasor.

  Subsequently, the space synchronization phasor calculation unit 213 calculates a space synchronization phasor (step S213). The space synchronization phasor is calculated according to the following equation (80).

Where φ ₁ (t) and φ ₂ (t) are the synchronized phasor phase angles of node 1 and node 2, respectively. Thus, a spatially synchronized phasor is defined as a synchronized phasor phase angle difference of different nodes on the same time section.

  Finally, each value calculated by the above-described procedure is output as a measurement result (step S214). Then, it is determined whether or not termination is instructed (step S215). If termination is not instructed (NO in step S215), the processing in step S201 and subsequent steps is repeatedly executed. If termination is instructed (YES in step S215), the series of processing ends.

(F5: Simulation example)
The results of evaluating the multiple scale method of the second embodiment by simulation (Case 3) are shown below. The parameters used for the fundamental wave simulation of Case 3 are shown in the following table.

  The frequency calculation reference table used for the simulation of case 3 is shown below. This frequency calculation reference table is calculated in advance.

  First, according to the parameters of case 3, the input waveform is defined according to the following equation (81).

  Simulation results of the synchronized phasor and time synchronized phasor measurement are shown in FIGS. 45 to 47, respectively. FIG. 45 is a diagram illustrating simulation results for the synchronized phasor in the fundamental wave simulation of case 3. FIG. FIG. 46 is a diagram illustrating a simulation result of the synchronized phasor phase angle in the fundamental wave simulation of case 3. In FIG. FIG. 47 is a diagram showing simulation results for the time-synchronized phasor in the fundamental wave simulation of case 3. FIG.

  In the graph shown in FIG. 45, the horizontal axis represents the real part of the synchronized phasor, and the vertical axis represents the imaginary part of the synchronized phasor. In this way, the dynamic measurement result of the synchronized phasor on the complex plane can be visualized as a diagram. In this simulation, it is assumed that only the fundamental wave is considered and no harmonic component is present. Therefore, the measurement result of the synchronized phasor is a rotating circle vector. The fact that the imaginary part of the synchronized phasor can be measured simultaneously is a great advantage of the second embodiment.

As shown in FIG. 46, the synchronized phasor phase angle repeatedly varies in the range of −180 ° to 180 °. In this simulation, it is assumed that only the fundamental wave is considered and no harmonic component is present, and therefore the same synchronized phasor is used between different scales (gauge sampling points N _g = 5 and gauge sampling points N _g = 25). A measured value of the phase angle is obtained. This measurement result (simulation result) proves that the logic of the multi-scale method is correct.

Theoretically, the time synchronization phasor is defined according to the following equation (82).
_{φ TP = (50-49) × 360} /50 = 7.2 (deg) ... (82)
It can be seen that the above theoretical calculation results agree with the measurement results shown in FIG. In this simulation, since only the fundamental wave is considered and no harmonic component is present, it is completely the same between different scales (gauge sampling points N _g = 5 and gauge sampling points N _g = 25). Time synchronized phasor measurements are obtained. This measurement result (simulation result) also proves that the logic of the multiscale method is correct.

(F6: Comparison with measured value)
The result of measuring a synchronized phasor of an actual waveform by using again the time waveform measured from the actual power system used in case 2 described above is shown. The measured result is referred to as Case 4 for convenience of explanation.

  The parameters used for comparison with the measured values of Case 4 are shown in the following table.

  In addition, a frequency calculation reference table used for comparison with the actual measurement value of Case 4 is shown below. This frequency calculation reference table is calculated in advance.

Results of comparison with the actual measurement values of Case 4 are shown in FIGS.
FIG. 48 is a diagram illustrating the measurement result of the synchronized phasor in the actual measurement example of case 4. 49 is an enlarged view of the measurement result of the synchronized phasor shown in FIG. FIG. 50 is a diagram illustrating a measurement result of the synchronized phasor phase angle in the measurement example of case 4. 51 and 52 are diagrams showing measurement results of the time-synchronized phasor in the actual measurement example of case 4. FIG.

  FIG. 48 shows a dynamic measurement result of the synchronized phasor on the complex plane of the real waveform. Since the actually measured time waveform includes a plurality of harmonic components, the measurement result of the synchronized phasor basically shows a circle, but the outer circumference of the circle is thick. FIG. 49 shows an enlarged view of the time waveform shown in FIG. 48 in order to confirm the harmonic component. As shown in FIG. 49, the influence of the harmonic component included in the actually measured time waveform can be confirmed.

As shown in FIG. 50, the synchronized phasor phase angle repeatedly fluctuates in the range of −180 ° to 180 °. Between different scales (gauge sampling points N _g = 5 and gauge sampling points N _g = 25), almost the same measurement value of the synchronized phasor phase angle is obtained even though many harmonic components exist. I understand that. The reason for this is that while the data collection sampling frequency is 4000 Hz, the gauge sampling frequencies of the two scales are 235.29 Hz and 34.19 Hz, respectively. This is thought to be due to a significant reduction.

  51 and 52 show the measurement results of the time synchronization phasor in different time periods.

As shown in FIG. 51, in the measurement on the scale of the number of gauge sampling points N _g = 17, symmetry breaking occurs at the time of 0.09875 seconds. As a result, the time synchronization phasor becomes zero and the synchronization phasor phase angle is latched, so that the time synchronization phasor changes in a pulse shape at 0.132 seconds. The value is about 5.4 degrees. Note that the change amount of the synchronized phasor phase angle can be calculated as shown in the following equation (83) in the unit of one hour.

φ ₁ = 360 × 60/4000 = 5.4 (deg) (83)
According to the above-described processing procedure, when a symmetry breaking occurs at any scale in a certain step, the synchronized phasor amount of another scale in the same step is used. That is, the spatially synchronized phasor is measured using only the measured amount of the synchronized phasor phase angle in which symmetry is maintained. On the other hand, if symmetry breaking occurs at all scales, it can be determined that a power failure or failure has occurred. That is, in the multi-scale method, it is determined that a power failure or a system failure has occurred based on the information that the symmetry is broken at the same time in all the multi-scales. For example, the UPS is turned on or the relay protection device is used. Apply and perform fast startup of failures.

FIG. 52 shows the result of additional verification of symmetry breaking and the influence of harmonic components. In the measurement result of the number of gauge sampling points N _g = 17 in the time zone of 0.2 to 0.4 seconds, symmetry breaking occurs twice at 0.307 seconds and 0.332 seconds. On the other hand, in the measurement result of scale N _g = 117, symmetry breaking occurs only once for 0.26125 seconds. Thus, it can be said that the larger the scale, the smaller the number of occurrences of symmetry breaking, and the lower the influence of harmonic components.

  Note that even if the symmetry breaking occurs at the large scale, the symmetry is maintained at the small scale, so the voltage flicker phenomenon in the power system exists stochastically, and there is a point at one scale. It is not preferable to eliminate the data because it is bad. Except in the case of a complete power failure of the power system, all input data is valid, and even if symmetry breaking occurs in some scales, it is valid data in other scales. Thus, the multi-scale method is a compatible method that can be applied to various systems.

  As described above, the influence of the harmonic component of the actual waveform can be investigated by measuring the time-synchronized phasor.

[G. Embodiment 3]
As the third embodiment, the above-described multiscale method is applied, and the active power is obtained by using the gauge power group or the gauge differential power group proposed in the above-mentioned Patent Document 2 already filed by the present inventor. A method for measuring reactive power and impedance will be described.

  Hereinafter, the expression expansion of the gauge power group and the gauge differential power group will be described. As for an apparatus that implements the measurement method of the third embodiment, the signal processing apparatus 100 and its processing method described in the first embodiment or the synchronized phasor measurement apparatus 200 described in the second embodiment. Since it is similar to the processing method, detailed description will not be repeated. Hereinafter, the gauge power group or the gauge differential power group will be described.

(G1: Gauge power group)
FIG. 53 is a diagram illustrating a gauge power group on a complex plane. Three voltage rotation vectors on the complex plane shown in FIG. 53 are defined according to the following equation (84).

Where V is the AC voltage amplitude, ω is the rotational angular velocity, T _g is the gauge sampling period, α _g is the gauge rotational phase angle at T _g , and φ is the voltage-current phase angle. The three voltage rotation vectors shown in the equation (84) are a gauge voltage group.

  Further, three current rotation vectors on the complex plane shown in FIG. 53 are defined according to the following equation (85).

  However, I is a current amplitude, and the three current rotation vectors shown in the equation (85) are a gauge current group.

  The above-mentioned gauge voltage group and gauge current group are combined to form a gauge power group. Similar to the technique disclosed in Patent Document 2, a vector group table of the gauge power group can be created and the symmetry of the gauge power group can be considered.

  The real part instantaneous value of the voltage rotation vector shown in FIG. 53 is calculated according to the following equation (86), and the real part instantaneous value of the current rotation vector is calculated according to the following equation (87).

  Re in the above equations (86) and (87) indicates the real part of the complex number. The real number group table of the gauge power group is shown in the following table.

Using this real group table, various invariants of the gauge power group can be calculated. As a typical example of such an invariant, a frequency coefficient is shown below. The frequency coefficient f _C of the gauge power group is calculated according to the equation (88) by the above equations (86) and (87). Thus, the symmetry breaking index of the gauge power group can be set as shown in Equation (89).

  When the above equation (89) is satisfied, the calculation of the gauge power group is stopped, and the measurement value one step before is latched. In this case, the new gauge active power is calculated according to the following equation (90), and the gauge reactive power is calculated according to the following equation (91).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table. Furthermore, active power and reactive power are calculated according to the following formulas (92) and (93), respectively, based on the above result and the definition of power.

  Furthermore, the impedance is calculated according to the following equation (94).

However, _Ig is a gauge current. The above equation (94) provides a highly accurate impedance measurement method having a distance relay function and a frequency correction function.

(G2: Gauge differential power group)
FIG. 54 is a diagram illustrating a gauge differential power group on a complex plane. Three differential voltage rotation vectors on the complex plane shown in FIG. 54 are defined according to the following equation (95).

Where V is the AC voltage amplitude, ω is the rotational angular velocity, T _g is the gauge sampling period, α _g is the gauge rotational phase angle at T _g , and φ is the voltage-current phase angle. The three voltage rotation vectors shown in the equation (95) are a gauge differential voltage group.

  Further, three differential current rotation vectors on the complex plane shown in FIG. 54 are defined according to the following equation (96).

  However, I is a current amplitude, and the three current rotation vectors shown in the equation (96) are a gauge differential current group.

  The above-described gauge differential voltage group and gauge differential current group are combined to form a gauge differential power group. Similar to the technique disclosed in Patent Document 2, a vector group table of the gauge differential power group can be created and the symmetry of the gauge differential power group can be considered.

  The real part instantaneous value of the differential voltage rotation vector shown in FIG. 54 is calculated according to the following equation (97), and the real part instantaneous value of the differential current rotation vector is calculated according to the following equation (98).

  Re in the above equations (97) and (98) represents the real part of the complex number. The real number group table of the gauge differential power group is shown in the following table.

Using this real group table, various invariants of the gauge differential power group can be calculated. As a typical example of such an invariant, a frequency coefficient is shown below. The frequency coefficient f _C of the gauge differential power group is calculated according to the equation (99) by the above equations (97) and (98). Thus, the symmetry breaking index of the gauge differential power group can be set as shown in equation (100).

  When the above equation (100) is satisfied, the calculation of the gauge differential power group is stopped, and the measurement value one step before is latched. In this case, the new gauge difference active power is calculated according to the following equation (101), and the gauge difference reactive power is calculated according to the following equation (102).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table. Furthermore, active power and reactive power are calculated according to the following formulas (103) and (104), respectively, based on the above result and the definition of power.

  Further, the impedance is calculated according to the following equation (105).

Where I _gd is the gauge differential current. The above equation (105) provides a highly accurate impedance measurement method having a function of a distance relay and a frequency correction function.

[H. Embodiment 4]
As the fourth embodiment, the above-described multi-scale method is applied, and the gauge double voltage group or the gauge differential double voltage group proposed in Japanese Patent Application No. 2013-11438 already filed by the present inventor is used. A method for measuring the phase difference angle between power system voltages or the phase difference angle between currents will be described.

  Hereinafter, the expression expansion of the gauge dual voltage group and the gauge differential dual voltage group will be described. As for an apparatus that implements the measurement method according to the fourth embodiment, the signal processing apparatus 100 and its processing method described in the first embodiment or the synchronized phasor measurement apparatus 200 described in the second embodiment. Since it is similar to the processing method, detailed description will not be repeated. Hereinafter, the gauge dual voltage group and the gauge differential dual voltage group will be described.

(H1: Gauge dual voltage group)
FIG. 55 is a diagram illustrating a gauge dual voltage group on a complex plane. Three voltage rotation vectors of the terminal A on the complex plane shown in FIG. 55 are defined according to the following equation (106).

Where V _A is the voltage amplitude at terminal A, ω is the rotational angular velocity, T _g is the gauge sampling period, α _g is the gauge rotational phase angle at T _g , and φ is the bi-voltage phase angle is there. The three voltage rotation vectors shown in the equation (106) are gauge voltage groups.

  Similarly, three voltage rotation vectors of terminal B on the complex plane shown in FIG. 55 are defined according to the following equation (107).

However, V _B is the voltage amplitude of the terminal B. The three voltage rotation vectors shown in the equation (107) are a gauge voltage group.

  The above-described gauge voltage group at the terminal A and the gauge voltage group at the terminal B are combined to form a gauge double voltage group. Similar to the technique disclosed in Japanese Patent Application No. 2013-114381, the vector group table of the gauge bivoltage group can be created and the symmetry of the gauge bivoltage group can be considered.

  55, the real part instantaneous value of the voltage rotation vector at terminal A is calculated according to the following equation (108), and the real part instantaneous value of the voltage rotation vector at terminal B is calculated according to the following equation (109). .

  Re in the above equations (108) and (109) represents the real part of the complex number. The real number group table of the gauge dual voltage group is shown in the following table.

Using this real group table, various invariants of the gauge dual voltage group can be calculated. As a typical example of such an invariant, the frequency coefficient of the gauge twin voltage group is shown below. The frequency coefficient f _C of the gauge dual voltage group is calculated according to the equation (110) by the above equations (108) and (109). Thus, the symmetry breaking index of the gauge dual voltage group can be set as shown in the formula (111).

  When the above equation (111) is satisfied, the calculation of the gauge dual voltage group is stopped, and the measurement value of the previous step is latched. In this case, the new gauge effective bi-voltage is calculated according to the following equation (112), and the gauge invalid bi-voltage is calculated according to the following equation (113).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table. Further, the phase angle between the two voltages by the gauge voltage group is calculated according to the following equation (114).

(H2: Gauge differential dual voltage group)
FIG. 56 is a diagram illustrating a gauge differential dual voltage group on a complex plane. Three voltage rotation vectors of the terminal A on the complex plane shown in FIG. 56 are defined according to the following equation (115).

Where V _A is the voltage amplitude at terminal A, ω is the rotational angular velocity, T _g is the gauge sampling period, α _g is the gauge rotational phase angle at T _g , and φ is the bi-voltage phase angle is there. The three voltage rotation vectors shown in Equation (115) are a gauge differential voltage group.

  Similarly, three differential voltage rotation vectors of terminal B on the complex plane shown in FIG. 55 are defined according to the following equation (116).

However, V _B is the voltage amplitude of the terminal B. The three voltage rotation vectors shown in the equation (116) are a gauge differential voltage group.

  The above-described gauge differential voltage group at the terminal A and the gauge differential voltage group at the terminal B are combined to obtain a gauge differential dual voltage group. Similar to the technique disclosed in Japanese Patent Application No. 2013-114381, a vector group table of the gauge differential bi-voltage group can be created and the symmetry of the gauge differential bi-voltage group can be considered.

  56, the real part instantaneous value of the differential voltage rotation vector at the terminal A is calculated according to the following equation (117), and the real part instantaneous value of the differential voltage rotation vector at the terminal B is calculated according to the following equation (118). Is done.

  Re in the above equations (117) and (118) represents the real part of the complex number. The real number group table of the gauge differential dual voltage group is shown in the following table.

Using this real group table, various invariants of the gauge differential dual voltage group can be calculated. As a typical example of such an invariant, the frequency coefficient of the gauge differential dual voltage group is shown below. From the above-described equations (117) and (118), the frequency coefficient f _C of the gauge differential dual voltage group is calculated according to the equation (119). Thus, the symmetry breaking index of the gauge differential dual voltage group can be set as shown in equation (120).

  When the above equation (120) is satisfied, the calculation of the gauge differential dual voltage group is stopped, and the measurement value of the previous step is latched. In this case, the new gauge differential effective dual voltage is calculated according to the following equation (121), and the gauge differential invalid dual voltage is calculated according to the following equation (122).

However, _kf2 is a frequency conversion coefficient of a corresponding frequency calculation reference table. Further, the tangent function value of the phase angle between the two voltages by the gauge differential dual voltage group is calculated according to the following equation (123), and the phase angle between the two voltages itself is calculated according to the following equation (124).

[I. advantage]
According to the present embodiment, the present inventor has evolved from the single scale method (a method using one gauge sampling frequency) previously proposed to the multiscale method (a method using a plurality of gauge sampling frequencies), A new and higher performance measurement method is proposed. More specifically, a frequency calculation reference table defined by the data collection sampling frequency and the power system rated frequency is created, and the actual frequency of the power system is measured simultaneously using a plurality of gauge sampling frequencies. According to the present embodiment, a new gauge rotation phase angle and the like are defined, and a new measurement technique that exceeds the limit of the conventional sampling theorem and further expands the symmetry proposed in the prior application is realized.

[J. Other Embodiments]
The configuration illustrated as the above-described embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part of the configuration is omitted without departing from the gist of the present invention. It is also possible to change the configuration.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Signal processing apparatus, 101,201 Voltage instantaneous value data input part, 102 Frequency coefficient calculation part, 103,206 Symmetry breaking determination part, 104 Failure handling part, 105 Average frequency coefficient calculation part, 106 Gauge rotation phase angle calculation part, 107 Gauge rotation phase angle averaging unit, 108 Instantaneous frequency calculation unit, 109 Instantaneous frequency averaging unit, 110 Isolated operation discrimination unit, 111 Fundamental frequency selection unit, 112 Gauge differential voltage calculation unit, 113 Gauge differential voltage averaging unit, 114, 204 AC voltage amplitude calculation unit, 115 DC component calculation unit, 116 communication unit, 117, 214 storage unit, 118, 215 interface, 200 synchronous phasor measurement device, 202 average frequency calculation unit, 203 fundamental frequency coefficient selection unit, 205 Difference unit vector group generation unit, 207 gauge Minute effective phasor calculation unit, 208 gauge differential invalid synchronization phasor calculation unit, 209 synchronization phasor phase angle calculation unit, 210 synchronization phasor phase angle selection unit, 211 time synchronization phasor calculation unit, 212 synchronization phasor reception unit, 213 spatial synchronization phasor calculation Department.

Claims (11)

A signal processing device comprising:
Sampling means for sampling the measurement object at the collection sampling frequency and collecting instantaneous value data in time series;
First calculating means for calculating a gauge rotation phase angle corresponding to each of a plurality of gauge sampling frequencies,
Each of the plurality of gauge sampling frequencies is a value obtained by dividing the collected sampling frequency by a positive integer;
The signal processing device, wherein the first calculation means calculates each gauge rotation phase angle from instantaneous value data sampled at the collected sampling frequency with reference to a predetermined conversion factor for each gauge sampling frequency.   Whether or not symmetry corresponding to each of the plurality of gauge sampling frequencies is maintained by using the instantaneous value data of the four points constituting the symmetry group while being temporally continuous at the sampling interval at the collected sampling frequency. The signal processing apparatus according to claim 1, further comprising a first determination unit that determines whether or not each of them. The first determination unit determines a state occurring in a measurement target according to the number of gauge sampling frequencies determined to be non-symmetrical among the plurality of gauge sampling frequencies. 3. The signal processing apparatus according to 2.   The signal processing apparatus according to claim 1, wherein the plurality of gauge sampling frequencies are set according to a ratio of a fundamental wave component and a harmonic component included in a measurement target.   Second calculation means for calculating an instantaneous frequency corresponding to each of the plurality of gauge sampling frequencies based on each of the plurality of gauge sampling frequencies and a gauge rotation phase angle for each gauge sampling frequency is further provided. The signal processing device according to claim 1.   A first state of the measurement object is detected based on a change in average value of instantaneous frequencies corresponding to a relatively high gauge sampling frequency among the plurality of gauge sampling frequencies calculated by the second calculation means. The signal processing apparatus according to claim 5, further comprising two determination means.   The signal processing apparatus according to claim 5, further comprising an averaging unit that averages the instantaneous frequency calculated by the second calculation unit by a moving average process. The second calculating means calculates first and second instantaneous frequencies respectively corresponding to the first and second gauge sampling frequencies;
A current fundamental frequency is estimated based on the first and second instantaneous frequencies, and first and second gauge rotation phase angles corresponding to the first and second gauge sampling frequencies, respectively. The signal processing apparatus according to claim 5, further comprising a third calculation unit.   The first calculating means refers to a conversion coefficient prepared in advance for each of the plurality of fundamental frequencies, and a conversion coefficient directed to a measurement object whose frequency varies by referring to a predetermined conversion coefficient for each of the gauge sampling frequencies. The signal processing device according to any one of claims 1 to 8, wherein   The first calculation means applies a conversion factor for a stable second gauge sampling frequency to an unstable first gauge sampling frequency among the plurality of gauge sampling frequencies. The signal processing device according to claim 1. A signal processing method comprising:
A collection step for sampling the measurement object at the collection sampling frequency and collecting instantaneous value data in time series,
A first calculation step for calculating a gauge rotation phase angle corresponding to each of the plurality of gauge sampling frequencies,
Each of the plurality of gauge sampling frequencies is a value obtained by dividing the collected sampling frequency by a positive integer;
The first calculation step includes a step of calculating each gauge rotation phase angle from instantaneous value data sampled at the collected sampling frequency with reference to a predetermined conversion factor for each gauge sampling frequency. Processing method.

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