JPH11122821A - Single operation detector and detecting method for synchronous generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect single operation of a synchronous generator for supplying a generated power flow back to an AC commercial power supply surely regardless of fluctuation of load of consumer. SOLUTION: A frequency detector 31 detects the frequency of an output voltage signal SOUT in disturbed state to output a frequency detection signal SFRQ and a disturbance amplitude detector 32 extracts a signal having same frequency component as a disturbance signal contained in the frequency detection signal SFRQ to detect the amplitude of the same frequency component signal. Since a comparator 34 judges whether a synchronous generator is in single operation state or not based on the amplitude of the same frequency component signal detected by the disturbance amplitude detector 32 and a predetermined reference amplitude, single operation can be detected surely regardless of fluctuation in the frequency or voltage of a commercial power system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an isolated operation of a synchronous generator and a method of detecting an isolated operation of a synchronous generator, and more particularly to a method for returning surplus electric power from a private power generator having a synchronous generator to a commercial AC power system. The present invention relates to a synchronous generator single operation detection device and a synchronous generator single operation detection method for detecting whether or not a synchronous generator is in an isolated operation state when a power flow occurs.

[0002]

Shows the Background of the Invention independent operation detecting apparatus of the first conventional example Figure 10 the synchronous generator disclosed in Japanese Patent Laid-Open No. 8-172724.

An apparatus for detecting the isolated operation of the synchronous generator 70 includes a synchronous generator 70 that reversely flows generated power to a commercial AC power system.
And a voltage detecting unit 72 for detecting a generated voltage of the synchronous generator 70 in a power generating apparatus provided with an automatic voltage regulator 71 for adjusting a field current so that an output voltage of the synchronous generator becomes a predetermined value. An oscillation signal generating unit that generates an oscillation signal having a predetermined frequency and a predetermined amplitude, and supplies the oscillation signal to the automatic voltage regulator 71, and the automatic voltage regulator 71 changes a field current in response to the oscillation signal. 73 and a change in the output frequency of the synchronous generator 70 is detected by the frequency detection unit 77, and when the change is equal to or higher than the variably set discrimination level, it is determined that the synchronous generator 70 is operating alone, and the switch 78 , 79 for controlling the opening and closing of the power supply, and a level discrimination unit responsive to the output of the power detection unit 75 as the detected power increases. The discrimination level setting unit 76 that the discrimination level is set large for 4, and is configured to include.

Next, the operation will be described. Commercial AC power system 8
In 1, for example, in a state where the sending out circuit breaker 82 of the substation is closed, the synchronous generator 70 is in a non-single operation state. In this case, the reactive power of the synchronous generator 70 fluctuates due to the fluctuation signal given to the automatic voltage regulator 71, but the output voltage remains almost constant. On the other hand, when the sending-out circuit breaker of the substation is opened and the synchronous generator 70 enters the isolated operation state, the reactive power generated by the fluctuation signal given to the automatic voltage regulator 71 out of the power generated by the synchronous generator 70 becomes The output voltage fluctuates with little change.

[0005] Output voltage fluctuations cause fluctuations in power consumption of the load 80 to which the synchronous generator 70 supplies power, and consequently frequency fluctuations. By the way, the degree to which the fluctuation of the output voltage affects the frequency fluctuation changes according to the magnitude of the load 80. Accordingly, the discrimination level setting unit 76 sets the discrimination level for discriminating the level fluctuation of the frequency of the output voltage of the synchronous generator 70 as the generated power of the synchronous generator 70 detected by the power detection unit 75 increases. .

The discrimination level is set smaller as the power generated by the synchronous generator 70 detected by the power detection unit 75 increases. Therefore, when the feed-out circuit breaker 82 of the substation of the commercial AC power system 81 is opened, the isolated operation is performed by using the small discrimination level even when the load 11 of the synchronous generator 70 is small and the frequency fluctuation width is relatively small. Can be detected.

Second Prior Art FIG. 11 shows an isolated operation detection device for a synchronous generator disclosed in Japanese Patent Application Laid-Open No. 8-172725. 11, the same parts as those in FIG. 8 are denoted by the same reference numerals. The isolated operation detection device of the synchronous generator 70 includes a synchronous generator 70 that reversely flows generated power to the commercial AC power system and the synchronous generator 7.
In a power generator provided with an automatic voltage regulator 85 for adjusting a field current so that an output voltage of 0 becomes a predetermined value, a reactive power detection unit 86 for detecting a reactive power generated by a synchronous generator 70; A voltage detection unit 72 for detecting an output voltage of the synchronous generator 70, and a fluctuation signal generating unit for generating a fluctuation signal having a predetermined amplitude and changing a field current in response to the fluctuation signal by an automatic voltage regulator 85. 73, a first level discriminating unit 87 responsive to the output of the reactive power detecting unit 86 for discriminating that the fluctuation of the reactive power is less than the first discriminating level set by the first setting unit 90, In response to the output of the detection unit 92, it is determined that the fluctuation of the output voltage is equal to or higher than the second discrimination level set by the second setting unit 93. The second level discrimination unit 8 to discriminate
8, the output of the first level discriminating unit 87 and the output of the second level discriminating unit 88, the detected reactive power is less than the first discriminating level, and the detected output voltage is not less than the second discriminating level. At one time, a determination unit 89 that determines that the synchronous generator 70 is operating alone and controls the opening and closing of the switches 78 and 79 via the drive unit 94 is included.

Next, the operation will be described. Commercial AC power system 1
In, for example, in a state where the sending out circuit breaker of the substation is closed, the synchronous generator 70 is in a non-single operation state.
In this case, the reactive power of the synchronous generator 70 fluctuates due to the fluctuation signal given to the automatic voltage regulator 85, but the output voltage remains almost constant.
On the other hand, when the feed-out circuit breaker of the substation is opened and the synchronous generator 70 enters the isolated operation state, the reactive power generated by the fluctuation signal given to the automatic voltage regulator 85 out of the power generated by the synchronous generator 70 becomes The output voltage fluctuates with little change.

The output voltage fluctuation causes a fluctuation in power consumption of the load 80 to which the synchronous generator 70 supplies power, and consequently a frequency fluctuation. By the way, the degree to which the fluctuation of the output voltage affects the frequency fluctuation changes according to the magnitude of the load 80.

A synchronous generator 70 is connected to the commercial AC power system 81 from the commercial AC power system 81 via a distribution line in a state where the sending out circuit breaker 82 of the substation is closed. In a state where reverse power flow is possible, the fluctuation of the reactive power from the synchronous machine generator 70 detected by the reactive power detection unit 86 fluctuates in the same cycle as the fluctuation signal, and the fluctuation width of the reactive power is large.
The fluctuation of the reactive power is equal to or higher than the first discrimination level of the first level discrimination unit 87, and the fluctuation range of the output voltage of the synchronous generator 70 detected by the voltage detection unit 92 depends on the capacity of the commercial AC power system 81. Small because it is large.

In a state where the delivery circuit breaker 82 of the substation of the commercial AC power system 81 is shut off, the synchronous generator 70
The fluctuation of reactive power generated by
The output voltage becomes less than the discrimination level, and the output voltage has a large fluctuation width in the same cycle as the fluctuation signal, and the output voltage changes more than the second discrimination level. In this way, the two phenomena that the fluctuation of the reactive power is small and the fluctuation of the output voltage is large occur, so that the judgment unit 89
It can be determined that synchronous generator 70 is in the isolated operation state.

[0012]

The frequency of the commercial power system is constantly fluctuated due to the load fluctuation of the consumer. Therefore, in the first prior art synchronous generator single-operation detection device, the frequency of the commercial power system is affected by the load fluctuation. There is a problem in that an erroneous detection is made as an isolated operation state based on the accompanying frequency fluctuation.
In addition, the voltage of the commercial power system is constantly influenced by the load fluctuation of the consumer, and the reactive power is also constantly changed based on the fluctuation. Also, there is a problem that the operation state is erroneously detected as the isolated operation state based on the voltage fluctuation and the reactive power fluctuation accompanying the load fluctuation. Therefore, an object of the present invention is to
To provide a synchronous generator independent operation detection device capable of reliably detecting the independent operation state of a synchronous generator that generates reverse power flow to a commercial AC power system without being affected by a load change of a consumer. is there.

[0013]

According to the first aspect of the present invention,
An automatic voltage regulator that adjusts the field current so that the output voltage becomes a predetermined value is connected, and the synchronous generator that detects the isolated operation state of the synchronous generator that reversely flows the generated power to the commercial AC power system is used alone. In the operation detection device, a sway signal generating means for swaying the output voltage which is a voltage of an output voltage signal of the synchronous generator by outputting a sway signal having a predetermined frequency to the automatic voltage regulator, and Frequency detection means for detecting the frequency of the voltage signal and outputting a frequency detection signal, and an identical frequency component signal which is a signal having the same frequency component as the fluctuation signal included in the frequency detection signal based on the frequency detection signal And an amplitude detecting means for detecting the amplitude of the same frequency component signal, and the detected amplitude of the same frequency component signal and a predetermined reference amplitude. Zui and configure and a discriminating means for discriminating whether or not said synchronous generator is in islanding state.

According to the first aspect of the present invention, the sway signal generating means outputs the sway signal having a predetermined frequency to the automatic voltage regulator so that the output voltage is the voltage of the output voltage signal of the synchronous generator. Upset. On the other hand, the frequency detection means detects the frequency of the output voltage signal and outputs a frequency detection signal to the amplitude detection means. The amplitude detection means extracts the same frequency component signal, which is a signal having the same frequency component as the fluctuation signal included in the frequency detection signal, based on the frequency detection signal, and detects the amplitude of the same frequency component signal.

As a result, the determining means determines whether or not the synchronous generator is in the isolated operation state based on the amplitude of the same frequency component signal detected by the amplitude detecting means and a predetermined reference amplitude. According to a second aspect of the present invention, in the first aspect of the present invention, the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the frequency detection signal, Rectifying means for performing full-wave rectification of the same component signal and outputting a full-wave rectified signal; and low-pass filter means for detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectified signal. And comprising.

According to the second aspect of the present invention, in addition to the function of the first aspect, the same component signal extracting means of the amplitude detecting means has the same frequency component as the fluctuation signal from the frequency detection signal. The component signal is extracted and output to the rectifier. The rectifier performs full-wave rectification of the same component signal and outputs a full-wave rectified signal to the low-pass filter.

The low pass filter means detects the amplitude of the same frequency component signal by passing the low frequency component of the full wave rectified signal. According to a third aspect of the present invention, in the first aspect, the amplitude detecting means includes a Fourier transform detecting means for detecting an amplitude of the same frequency component signal by performing a Fourier transform of the frequency detection signal. Constitute.

According to the third aspect of the invention, in addition to the operation of the first aspect, the Fourier transform detecting means of the amplitude detecting means performs the Fourier transform of the frequency detection signal to thereby obtain the same frequency component signal. Detect the amplitude.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the discriminating means determines that the amplitude of the detected same frequency component signal is larger than a predetermined reference amplitude. In such a case, the synchronous generator is configured to determine that it is in an isolated operation state.

According to the fourth aspect of the present invention, in addition to the operation of the first aspect of the present invention,
The determining means determines that the synchronous generator is in the isolated operation state when the detected amplitude of the same frequency component signal is larger than a predetermined reference amplitude.

According to a fifth aspect of the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the isolated operation detection device for a synchronous generator for detecting an isolated operation state, the output voltage is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Rocking signal generation means for rocking, reactive power detection means for detecting reactive power based on the output voltage and output current of the synchronous generator, and outputting a reactive power detection signal; and An amplitude for extracting an identical frequency component signal which is a signal having the same frequency component as the fluctuation signal included in the reactive power detection signal, and detecting an amplitude of the identical frequency component signal; Means out, configure and a discriminating means for discriminating whether or not said synchronous generator is in the islanding operation state based on reference amplitude amplitude and predetermined identical frequency component signal above detection.

According to the fifth aspect of the present invention, the sway signal generating means outputs the sway signal having a predetermined frequency to the automatic voltage regulator, so that the output voltage is the voltage of the output voltage signal of the synchronous generator. Upset. On the other hand, the reactive power detecting means detects the reactive power based on the output voltage and the output current of the synchronous generator, and outputs a reactive power detection signal to the amplitude detecting means. The amplitude detecting means extracts the same frequency component signal, which is a signal having the same frequency component as the fluctuation signal included in the reactive power detection signal, based on the reactive power detection signal, and detects the amplitude of the same frequency component signal. The determination means determines whether or not the synchronous generator is in an isolated operation state based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the reactive power detection signal. Extraction means, rectification means for performing full-wave rectification of the same component signal to output a full-wave rectification signal, and detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectification signal And low-pass filter means.

According to the sixth aspect of the present invention, in addition to the function of the fifth aspect, the same component signal extracting means of the amplitude detecting means has the same frequency component as the fluctuation signal from the reactive power detection signal. The same component signal is extracted. The rectifier performs full-wave rectification of the same component signal extracted by the same component signal extractor and outputs a full-wave rectified signal to the low-pass filter. The low-pass filter detects the amplitude of the same frequency component signal by passing the low frequency component of the full-wave rectified signal.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, the amplitude detecting means performs a Fourier transform of the reactive power detection signal to detect an amplitude of the same frequency component signal. Means are provided. According to the seventh aspect of the present invention, in addition to the operation of the fifth aspect, the Fourier transform detecting means of the amplitude detecting means performs the Fourier transform of the reactive power detection signal to reduce the amplitude of the same frequency component signal. To detect.

According to an eighth aspect of the present invention, in the invention according to any one of the fifth to seventh aspects, the discriminating means determines that an amplitude of the detected same frequency component signal is smaller than a predetermined reference amplitude. In this case, it is determined that the synchronous generator is in the isolated operation state. According to the invention described in claim 8, in addition to the effect of the invention described in any one of claims 5 to 7, in addition to the function of the invention, the determining means determines that the detected amplitude of the same frequency component signal is larger than a predetermined reference amplitude. If it is smaller, it is determined that the synchronous generator is in an isolated operation state.

According to a ninth aspect of the present invention, there is provided a synchronous generator which is connected with an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the isolated operation detection device for a synchronous generator for detecting an isolated operation state, the output voltage is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Rocking signal generating means for rocking, and detecting the field current,
Field current detection means for outputting a field current detection signal; amplitude detection means for detecting the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal from the field current detection signal; Determining means for determining whether or not the synchronous generator is in an isolated operation state based on the amplitude of the frequency component signal and a predetermined reference amplitude.

According to the ninth aspect of the present invention, the sway signal generating means outputs a sway signal having a predetermined frequency to the automatic voltage regulator to output the voltage of the output voltage signal of the synchronous generator. Upset. On the other hand, the field voltage detecting means detects the field current based on the output of the automatic voltage regulator, and outputs a field current detection signal to the amplitude detecting means. The amplitude detecting means detects the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal from the field current detection signal.

As a result, the determining means determines whether or not the synchronous generator is in the isolated operation state based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude.
According to a tenth aspect of the present invention, in the fifth aspect of the invention, the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the field current detection signal. Rectifying means for performing full-wave rectification of the same component signal and outputting a full-wave rectified signal;
Low-pass filter means for detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectified signal.

According to the tenth aspect, the fifth aspect is provided.
In addition to the function of the invention described above, the same component signal extracting means of the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the field current detection signal and outputs the same to the rectifying means. The rectifier performs full-wave rectification of the same component signal and outputs a full-wave rectified signal to the low-pass filter. Thus, the low-pass filter means detects the amplitude of the same frequency component signal by passing the low frequency component of the full-wave rectified signal.

According to an eleventh aspect of the present invention, in the fifth aspect of the invention, the amplitude detecting means performs a Fourier transform of the field current detection signal to detect an amplitude of the same frequency component signal. It comprises detection means. According to the eleventh aspect of the present invention, in addition to the function of the fifth aspect, the amplitude detecting means Fourier transform detecting means performs the Fourier transform of the field current detection signal to thereby obtain the amplitude of the same frequency component signal. Is detected.

According to a twelfth aspect of the present invention, in the invention according to any one of the fifth to seventh aspects, the discriminating means determines that an amplitude of the detected same frequency component signal is smaller than a predetermined reference amplitude. In such a case, the synchronous generator is configured to determine that it is in an isolated operation state. Claim 1
According to the second aspect of the present invention, in addition to the operation of the fifth aspect of the present invention, the determining means determines that the amplitude of the detected same frequency component signal is smaller than a predetermined reference amplitude. Then, it is determined that the synchronous generator is in the isolated operation state.

According to a thirteenth aspect of the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the isolated operation detection device for a synchronous generator for detecting an isolated operation state, the output voltage is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Signal generation means for fluctuating, a field voltage detection means for detecting a field voltage proportional to the field current and outputting a field voltage detection signal, and the same as the fluctuation signal from the field voltage detection signal Amplitude detection means for detecting the amplitude of the same frequency component signal having the frequency component of: and the synchronous generator alone based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude. Discriminating means for discriminating whether or not the rolling state, configured with a.

According to the thirteenth aspect of the present invention, the sway signal generating means outputs the sway signal having a predetermined frequency to the automatic voltage regulator, thereby outputting the output voltage which is the voltage of the output voltage signal of the synchronous generator. Upset. On the other hand, the field voltage detection means detects a field voltage proportional to the field current based on the output of the automatic voltage regulator, and outputs a field voltage detection signal to the amplitude detection means. The amplitude detecting means detects the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal from the field voltage detection signal.

As a result, the determining means determines whether or not the synchronous generator is in the isolated operation state based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude.

According to a fourteenth aspect of the present invention, in the thirteenth aspect, the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the field voltage detection signal. Signal extracting means, rectifying means for performing full-wave rectification of the same component signal to output a full-wave rectified signal, and detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectified signal And low-pass filter means.

According to the fourteenth aspect of the present invention, the first aspect is provided.
In addition to the function of the invention described in the third aspect, the same component signal extracting means of the amplitude detecting means extracts the same component signal having the same frequency component as the fluctuation signal from the field voltage detection signal, and outputs the same to the rectifying means. The rectifier performs full-wave rectification of the same component signal and outputs a full-wave rectified signal to the low-pass filter.
Thus, the low-pass filter means detects the amplitude of the same frequency component signal by passing the low frequency component of the full-wave rectified signal.

According to a fifteenth aspect, in the thirteenth aspect, the amplitude detecting means performs a Fourier transform of the field voltage detection signal to detect an amplitude of the same frequency component signal. It comprises detection means. According to the invention of claim 15, claim 1 is
In addition to the operation of the invention described in the third aspect, the amplitude detecting means Fourier transform detecting means detects the amplitude of the same frequency component signal by performing a Fourier transform of the field voltage detection signal.

According to a sixteenth aspect of the present invention, in the invention according to any one of the thirteenth to fifteenth aspects, the discriminating means determines that the amplitude of the detected same frequency component signal is smaller than a predetermined reference amplitude. In such a case, the synchronous generator is configured to determine that it is in an isolated operation state. According to the invention described in claim 16, claims 13 to 1 are provided.
In addition to the operation of the invention described in any one of the fifth to fifth aspects, the determining means determines that the synchronous generator is in the isolated operation state when the detected amplitude of the same frequency component signal is smaller than a predetermined reference amplitude. .

According to a seventeenth aspect of the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the method for detecting an isolated operation of a synchronous generator for detecting an isolated operation state, the output voltage which is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. An output voltage oscillating step of oscillating, a frequency detecting step of detecting the frequency of the output voltage signal, and, based on the detected frequency of the output voltage signal, the same frequency component as the oscillating signal included in the output voltage signal An amplitude detection step of detecting the amplitude of the signal of the frequency component, and the synchronous generator based on the amplitude of the detected signal and a predetermined reference amplitude. A determination step of determining whether or not the operating state, is configured with a.

According to the seventeenth aspect of the present invention, in the output voltage fluctuation step, the output voltage which is the voltage of the output voltage signal of the synchronous generator is output by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. Upset. On the other hand, the frequency detecting step detects a frequency of the output voltage signal. The amplitude detecting step extracts the same frequency component as the sway signal included in the output voltage signal based on the frequency of the output voltage signal detected in the frequency detecting step, and detects the amplitude of the signal of the frequency component. The determining step determines whether or not the synchronous generator is in the isolated operation state based on the amplitude of the signal detected in the amplitude detecting step and a predetermined reference amplitude.

According to the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the method for detecting an isolated operation of a synchronous generator for detecting an isolated operation state, the output voltage which is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. An output voltage oscillating step for oscillating, a reactive power detecting step for detecting a reactive power based on an output voltage and an output current of the synchronous generator, and the oscillating signal included in the reactive power signal corresponding to the detected reactive power The same frequency component is extracted as the amplitude detection step of detecting the amplitude of the signal of the frequency component, and based on the detected signal amplitude and a predetermined reference amplitude, A determining step of the period generator to determine whether it is in the islanding operation state, and configured with a.

According to the eighteenth aspect of the present invention, in the output voltage fluctuation step, the output voltage which is a voltage of the output voltage signal of the synchronous generator is output by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. Perturb the voltage. On the other hand, the reactive power detection step detects reactive power based on the output voltage and output current of the synchronous generator. The amplitude detection step extracts the same frequency component as the fluctuation signal included in the reactive power signal corresponding to the reactive power detected in the reactive power detection step, and detects the amplitude of the signal of the frequency component. The determining step determines whether or not the synchronous generator is in an isolated operation state based on the amplitude of the signal detected in the amplitude detecting step and a predetermined reference amplitude.

According to a nineteenth aspect of the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the method for detecting an isolated operation of a synchronous generator for detecting an isolated operation state, the output voltage which is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. An output voltage oscillating step of oscillating, a field current detecting step of detecting the field current, and based on the detected field current, the output voltage signal included in the output voltage signal from a variable frequency component of the field current. An amplitude detection step of extracting the same frequency component as the motion signal and detecting the amplitude of the signal of the frequency component; and performing the synchronization based on the amplitude of the detected signal and a predetermined reference amplitude. Electrical machine configured with a determination step of determining whether the islanding state, the.

According to the nineteenth aspect of the present invention, in the output voltage fluctuation step, the output voltage which is the voltage of the output voltage signal of the synchronous generator is output by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. Upset. On the other hand, the field current detecting step detects the field current based on the output of the automatic voltage regulator. In the amplitude detection step, in the field current detection step, based on the detected field current, the same frequency component as the fluctuation signal included in the output voltage signal is extracted from the fluctuation frequency component of the field current, and the Detect the amplitude of the signal. The determining step determines whether or not the synchronous generator is in the isolated operation state based on the amplitude of the signal detected in the amplitude detecting step and a predetermined reference amplitude.

According to a twentieth aspect of the present invention, there is provided a synchronous generator which is connected to an automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value, and reversely flows generated power to a commercial AC power system. In the method for detecting an isolated operation of a synchronous generator for detecting an isolated operation state, the output voltage which is a voltage of an output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. An output voltage swinging step of swinging the field voltage, a field voltage detecting step of detecting a field voltage, based on the detected field voltage,
An amplitude detection step of extracting the same frequency component as the fluctuation signal included in the output voltage signal from the fluctuation frequency component of the field voltage, and detecting the amplitude of the signal of the frequency component;
A determination step of determining whether or not the synchronous generator is in an isolated operation state based on the detected signal amplitude and a predetermined reference amplitude.

According to the twentieth aspect, in the output voltage fluctuation step, the output voltage which is the voltage of the output voltage signal of the synchronous generator is output by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. Upset. On the other hand, the field voltage detecting step detects the field voltage based on the output of the automatic voltage regulator. In the amplitude detection step, in the field voltage detection step, based on the detected field voltage, the same frequency component as the fluctuation signal included in the output voltage signal is extracted from the fluctuation frequency component of the field voltage. Detect the amplitude of the signal. The determining step determines whether or not the synchronous generator is in the isolated operation state based on the amplitude of the signal detected in the amplitude detecting step and a predetermined reference amplitude.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the drawings. First Embodiment FIG. 1 shows a schematic configuration block diagram of a power generation system including an isolated operation detection device for a synchronous generator according to a first embodiment. The power generation system 10 is roughly divided into a prime mover 11 that converts energy such as coal, oil, gas, and the like into mechanical energy to generate a driving force, and is driven by the prime mover 11 and generated by the rotation speed of its rotating shaft. , A circuit breaker 14 for electrically disconnecting the synchronous generator 12 from the commercial power system 13 based on the cutoff control signal SOFF, and an output voltage signal SOU of the synchronous generator 12
While detecting the voltage VOUT of T, the field current is adjusted based on the detected output voltage VOUT of the synchronous generator 12 and a fluctuation signal SVIB described later so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value. Voltage regulator (A
VR) 15 and a sway signal SVIB, and based on the output voltage signal SOUT of the synchronous generator 12, determines whether or not the synchronous generator 12 is operating alone. And an islanding operation detecting device 16 that shuts off the circuit breaker 14 by the shutoff control signal SOFF.

The automatic voltage regulator 15 is set with a reference voltage VREF, and outputs a reference voltage signal SVREF corresponding to the set reference voltage VREF, and is proportional to the voltage VOUT of the output voltage signal SOUT. A voltage detector 21 for generating and outputting a detection voltage signal SOUT1 having a voltage VOUT1
And the voltage VVIB of the shake signal SVIB and the reference voltage signal SVREF
A voltage VADD (= VR) is obtained by subtracting the detected voltage VOUT1 of the detected voltage signal SOUT1 from the added voltage obtained by adding the voltage VREF.
EF + VVIB−VOUT1), and an adder 22 that outputs an addition result signal SADD, and a deviation amplifier 23 that amplifies the voltage VADD of the addition result signal SADD and outputs a deviation amplification signal ASADD.
And a power amplifier 24 that amplifies the power of the deviation amplification signal ASADD and adjusts the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value.

The islanding detection device 16 includes a vibration signal generator 3 that outputs a vibration signal SVIB having a predetermined frequency.
0, a frequency detector 31 which detects the frequency of the output voltage signal SOUT of the synchronous generator 12 and outputs a frequency detection signal SFRQ, and detects the amplitude of a signal having the same frequency component as the fluctuation signal SVIB from the frequency detection signal SFRQ A swing amplitude detector 32 for outputting an amplitude detection signal SPP having a voltage VPP corresponding to the detected amplitude, and a reference amplitude setting for outputting a reference amplitude signal SPREF having a voltage VPREF corresponding to a predetermined amplitude. 33 and the voltage V of the amplitude detection signal SPP.
By comparing PP with the voltage VPREF of the reference amplitude signal SPREF, the amplitude of a signal having the same frequency component as the sway signal SVIB corresponding to the amplitude detection signal SPP is obtained.
When the amplitude is larger than the amplitude corresponding to the above, that is, when the fluctuation of the output voltage is large, the comparator that determines that the synchronous generator 12 is operating alone and outputs the shutoff control signal SOFF to shut off the circuit breaker 14 is output. 34.

FIG. 2 shows two examples of the detailed configuration of the fluctuation amplitude detector 32. A first configuration example of the fluctuation amplitude detector 32 is shown in FIG.
As shown in (a), of the frequency detection signal SFRQ input from the frequency detector 31, only a predetermined frequency band component corresponding to the same frequency component as the fluctuation signal SVIB is passed,
Bandpass filter 32 for outputting bandpass signal SBP
A, an absolute value detector 32B that performs full-wave rectification of the band-pass signal SBP and outputs an absolute value signal ABS, and a fluctuation signal included in the frequency detection signal SFRQ that passes only the low frequency components of the absolute value signal SABS. And a low-pass filter 32C that outputs an amplitude detection signal SPP having a voltage VPP corresponding to the amplitude of a signal having the same frequency component as that of SVIB.

Next, the operation of the first example of the configuration of the fluctuation amplitude detector 32 will be described. The bandpass filter 32A is
Frequency detection signal SFRQ input from frequency detector 31
Of these, only a predetermined frequency band component corresponding to the same frequency component as the motion signal SVIB is passed, and a bandpass signal SBP having the same frequency component as the motion signal SVIB is output to the absolute value detector 32B. The absolute value detector 32B performs full-wave rectification of the bandpass signal SBP, and outputs the absolute value signal ABS to the low-pass filter 32C.

Thus, the low-pass filter 32C allows only the low frequency component of the absolute value signal SABS proportional to the amplitude of the signal having the same frequency component as the motion signal SVIB to pass, and the signal having the same frequency component as the motion signal SVIB. Is output to the comparator 34. The amplitude detection signal SPP having the voltage VPP corresponding to the amplitude On the other hand, the oscillation amplitude detector 3
In the second configuration example of FIG. 2, as shown in FIG. 2B, a Fourier transform of the frequency detection signal SFRQ is performed, and a voltage VPP corresponding to the amplitude of a signal having the same frequency component as the fluctuation signal SVIB is obtained.
Fourier transformer 3 for outputting amplitude detection signal SPP having
It is configured by 2D. In FIG. 2B, for the sake of simplicity of the illustration, the conversion formula is represented as a = SFRQ A = SPP.

Next, the operation of the second configuration example of the fluctuation amplitude detector 32 will be described. First, based on the equations (2) and (3), the frequency detection signal SFRQ is sectionally integrated with the period T (see FIG. 3) of the sway signal SVIB to obtain a cosine wave component Ax and a sine wave component Ay. Next, based on the equation (1), an amplitude detection signal SPP having a voltage VPP corresponding to the amplitude of a signal having the same frequency component as the fluctuation signal SVIB is obtained from the cosine wave component Ax and the sine wave component Ay. Will be output.

Next, prior to the description of the operation of the power generation system 10, the oscillation signal SVIB will be described. FIG. 3 shows an example of the sway signal output from the sway signal generator. FIG.
(A) is an example of a sway signal SVIB having a sine waveform, FIG. 3 (b) is an example of a sway signal SVIB having a rectangular waveform,
FIG. 3C shows an example of a swing signal SVIB having a triangular waveform.

The oscillation signal SVIB is not limited to these waveforms, but has the same period T, that is, the frequency 1
As long as the periodic function has / T, the same effect can be obtained regardless of any waveform. Next, the operation of the power generation system 10 will be described.
In the initial state, it is assumed that the circuit breaker 14 is in a non-blocking state. The synchronous generator 12 is driven by the prime mover 11 and outputs an output voltage signal SOUT. Thereby, the voltage detector 21 of the automatic voltage regulator 15 outputs the output voltage signal S
A detection voltage signal SOUT1 having a voltage VOUT1 proportional to the voltage VOUT of OUT is generated and output to the adder 22.

The reference voltage setting unit 20 outputs a reference voltage signal SVREF corresponding to the set reference voltage VREF to the adder 22. On the other hand, the sway signal generator 30 of the islanding detection device 16 outputs the sway signal S having a predetermined frequency.
VIB is output to the adder 22. By these, adder 2
2 is the voltage VVIB of the shake signal SVIB and the reference voltage signal SVR
The voltage VOUT1 of the detected voltage signal SOUT1 is subtracted from the added voltage obtained by adding the voltage VREF of the EF, and the voltage VADD (=
(VREF + VVIB-VOUT1) is output to the deviation amplifier 23.

The deviation amplifier 23 amplifies the voltage VADD of the addition result signal SADD and outputs a deviation amplification signal ASADD to the power amplifier 24. As a result, the power amplifier 24 amplifies the power of the deviation amplification signal ASADD and adjusts the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value, and the output voltage VOUT of the synchronous generator 12 is constant. Is controlled to be the voltage of

In parallel with these operations, the frequency detector 31 of the islanding operation detecting device 16 detects the frequency of the output voltage signal SOUT of the synchronous generator 12 and outputs the frequency detection signal SFRQ to the fluctuation amplitude detector 32. I do. Oscillation amplitude detector 32
2 detects the amplitude of a signal having the same frequency component as the fluctuation signal SVIB from the frequency detection signal SFRQ and converts the amplitude detection signal SPP having a voltage VPP corresponding to the detected amplitude into the comparator 34 by the configuration shown in FIG. Output to Further, the reference amplitude setting device 33 outputs to the comparator 34 a reference amplitude signal SPREF having a voltage VPREF corresponding to a predetermined amplitude.

As a result, the comparator 34 compares the voltage VPP of the amplitude detection signal SPP with the voltage VPREF of the reference amplitude signal SPREF, and compares the amplitude of the signal having the same frequency component as the fluctuation signal SVIB corresponding to the amplitude detection signal SPP. Is the reference amplitude signal SPR
When the amplitude is larger than the amplitude corresponding to EF, it is determined that the synchronous generator 12 is performing the independent operation. And the circuit breaker 14
In order to cut off the power, the synchronous generator 12 is electrically disconnected from the commercial power system 13 so that even if the delivery circuit breaker of the substation is open for work. In addition, the power generated by the synchronous generator 12 can be reliably prevented from flowing backward, and if the sending-out circuit breaker is closed again, the connection caused by the power flow being asynchronous can be performed. Property can be prevented.

As described above, according to the first embodiment, based on the frequency component of the output voltage signal SOUT of the synchronous generator 12, the synchronous power generation is performed based on the same frequency component frequency fluctuation as the sway signal SVIB. Since the isolated operation state of the generator 12 is detected, the isolated operation state of the synchronous generator 12 can be reliably detected without being affected by the frequency fluctuation and the voltage fluctuation of the commercial power system 13.

Second Embodiment FIG. 4 is a schematic block diagram of a power generation system including an isolated operation detection device for a synchronous generator according to a second embodiment. In FIG. 4, the same parts as those in the first embodiment of FIG. 1 are denoted by the same reference numerals. The power generation system 60 is roughly divided into a motor 11 that converts energy such as coal, oil, gas, and the like into mechanical energy to generate a driving force, and an AC that is driven by the motor 11 and generated by the rotation speed of its rotating shaft. Generator 12 whose frequency is determined, and a shutoff control signal SOF
A circuit breaker 14 for electrically disconnecting the synchronous generator 12 from the commercial power system 13 based on F, a voltage VOUT of an output voltage signal SOUT of the synchronous generator 12 are detected, and the detected synchronous generator 12 An automatic voltage regulator (AVR) 15 for adjusting the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value based on the output voltage VOUT and a swing signal SVIB described below, and a swing signal SVIB. Output, and determines whether or not the synchronous generator 12 is operating independently based on the output voltage signal SOUT and the output current signal SIOUT of the synchronous generator 12. And an islanding operation detecting device 61 that shuts off the circuit breaker 14 by the control unit.

Since the automatic voltage regulator 15 is the same as that of the first embodiment shown in FIG. 1, a detailed description thereof will be omitted. The islanding operation detection device 61 is disabled based on the shake signal generator 30 that outputs the shake signal SVIB having a predetermined frequency, the voltage VOUT of the output voltage signal SOUT of the synchronous generator 12, and the current IOUT of the output current signal SIOUT. Power detection signal SREAC
And a reactive power detection signal S
The amplitude of a signal having the same frequency component as the fluctuation signal SVIB is detected from the REAC, and a voltage VPP corresponding to the detected amplitude is detected.
A fluctuation amplitude detector 63 that outputs an amplitude detection signal SPP0 having 0, and a voltage VPREF0 corresponding to a predetermined amplitude.
And a reference amplitude setting device 64 that outputs a reference amplitude signal SPREF0 having the following formula: and a voltage VPP0 of the amplitude detection signal SPP0 and a voltage VPREF0 of the reference amplitude signal SPREF0. When the amplitude of the signal having the component is smaller than the amplitude corresponding to the reference amplitude signal SPREF0, that is, when the reactive power is small, it is determined that the synchronous generator 12 is operating alone and the breaker 14 is shut off. And a comparator 65 that outputs a shutoff control signal SOFF.

FIG. 5 shows two detailed configuration examples of the fluctuation amplitude detector 63. A first configuration example of the fluctuation amplitude detector 63 is shown in FIG.
As shown in (a), of the reactive power detection signal SREAC input from the frequency detector 31, only a predetermined frequency band component corresponding to the same frequency component as the fluctuation signal SVIB is passed, and a bandpass signal SBP0 is output. The bandpass fill 63A, an absolute value detector 63B that performs full-wave rectification of the bandpass signal SBP0 and outputs an absolute value signal SABS0, and passes only the low frequency components of the absolute value signal SABS0 to the reactive power detection signal SREAC A low-pass filter 63C that outputs an amplitude detection signal SPP0 having a voltage VPP0 corresponding to the amplitude of a signal having the same frequency component as the included shake signal SVIB
And is provided.

Next, the operation of the first example of the configuration of the fluctuation amplitude detector 63 will be described. The bandpass filter 63A is
The reactive power detection signal S input from the reactive power detector 62
In the REAC, only a predetermined frequency band component corresponding to the same frequency component as the sway signal SVIB is passed, and the sway signal
And outputs a bandpass signal SBP0 having the same frequency component to the absolute value detector 63B. The absolute value detector 63B performs full-wave rectification of the bandpass signal SBP0, and outputs the absolute value signal SABS
0 is output to the low-pass filter 63C.

Thus, the low-pass filter 63C allows only the low frequency component of the absolute value signal SABS0 proportional to the amplitude of the signal having the same frequency component as the motion signal SVIB to pass, and the signal having the same frequency component as the motion signal SVIB. Is output to the comparator 65 having an amplitude detection signal SPP0 having a voltage VPP0 corresponding to the amplitude of On the other hand, the second configuration example of the fluctuation amplitude detector 63 performs a Fourier transform of the reactive power detection signal SREAC as shown in FIG.
It comprises a Fourier transformer 63D that outputs an amplitude detection signal SPP0 having a voltage VPP0 corresponding to the amplitude of a signal having the same frequency component as VIB. In FIG. 5B, for simplification of the illustration, a = SREAC A = SPP0 and the conversion formula is represented.

Next, the operation of the second example of the configuration of the fluctuation amplitude detector 63 will be described. First, based on the equations (2) and (3), the reactive power detection signal SREAC is sectionally integrated at a period T (see FIG. 3) of the sway signal SVIB to obtain a cosine wave component Ax and a sine wave component Ay.

Next, based on the equation (1), the cosine wave component Ax
The amplitude detection signal SPP0 having the voltage VPP0 corresponding to the amplitude of the signal having the same frequency component as the fluctuation signal SVIB is obtained from the sine wave component Ay and output to the comparator 65. Next, the operation of the power generation system 60 will be described.
In the initial state, it is assumed that the circuit breaker 14 is in a non-blocking state. The synchronous generator 12 is driven by the prime mover 11 and outputs an output voltage signal SOUT. Thereby, the voltage detector 21 of the automatic voltage regulator 15 outputs the output voltage signal S
A detection voltage signal SOUT1 having a voltage VOUT1 proportional to the voltage VOUT of OUT is generated and output to the adder 22.

The reference voltage setting device 20 outputs a reference voltage signal SVREF corresponding to the set reference voltage VREF to the adder 22. On the other hand, the sway signal generator 30 of the isolated operation detection device 61 outputs the sway signal S having a predetermined frequency.
VIB is output to the adder 22.

Thus, the adder 22 outputs the oscillation signal S
The voltage VOUT1 of the detected voltage signal SOUT1 is subtracted from the added voltage obtained by adding the voltage VVIB of the VIB and the voltage VREF of the reference voltage signal SVREF to obtain a voltage VADD (= VREF + VVIB-VO).
UT1) is output to the deviation amplifier 23. The deviation amplifier 23 amplifies the voltage VADD of the addition result signal SADD and outputs the deviation amplification signal ASADD to the power amplifier 24.
Output to

As a result, the power amplifier 24 amplifies the power of the deviation amplification signal ASADD and adjusts the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value.
The output voltage VOUT of the synchronous generator 12 is controlled to be constant. In parallel with these actions,
The reactive power detector 62 of the isolated operation detection device 61 detects the reactive power based on the voltage VOUT of the output voltage signal SOUT of the synchronous generator 12 and the current IOUT of the output current signal SIOUT,
The reactive power detection signal SREAC is output to the fluctuation amplitude detector 63.

The fluctuation amplitude detector 63 detects the amplitude of a signal having the same frequency component as the fluctuation signal SVIB from the reactive power detection signal SREAC and generates a voltage VPP0 corresponding to the detected amplitude by the configuration shown in FIG. Having amplitude detection signal SP
P0 is output to the comparator 65. The reference amplitude setting device 64
Is a voltage VPREF0 corresponding to a predetermined amplitude.
Is output to the comparator 65.

As a result, the comparator 65 calculates the voltage VPP0 of the amplitude detection signal SPPO and the voltage VPRE of the reference amplitude signal SPREF0.
F0 is compared with the swing signal SV corresponding to the amplitude detection signal SPP0.
When the amplitude of the signal having the same frequency component as IB is smaller than the amplitude corresponding to the reference amplitude signal SPREF0,
When the reactive power is small, it is determined that the synchronous generator 12 is performing the isolated operation.

Then, a shutoff control signal SOFF is output to shut off the circuit breaker 14, and the synchronous generator 12 is connected to the commercial power system 1
3, the power generated by the synchronous generator 12 can be reliably prevented from flowing backward even when the delivery circuit breaker of the substation is open for work. At the same time, when the sending-out circuit breaker is closed again, it is possible to prevent the possibility of association due to the power flow being in an asynchronous state.

As described above, according to the second embodiment, since the independent operation state of the synchronous generator 12 is detected based on the reactive power of the synchronous generator 12, the frequency of the commercial power system 13 Fluctuations and voltage fluctuations,
The independent operation state of the synchronous generator 12 can be reliably detected.

Third Embodiment FIG. 6 is a schematic block diagram of a power generation system including an isolated operation detection device for a synchronous generator according to a third embodiment. 6, the same parts as those in the first embodiment in FIG. 1 are denoted by the same reference numerals. The power generation system 40 is roughly divided into a prime mover 11 that converts energy such as coal, oil, gas, and the like into mechanical energy to generate a driving force, and is driven by the prime mover 11 and generated by the rotational speed of its rotating shaft. Generator 12 whose frequency is determined, and a shutoff control signal SOF
Based on F, a circuit breaker 14 for electrically disconnecting the synchronous generator 12 from the commercial power system 13 and a voltage VOUT of an output voltage signal SOUT of the synchronous generator 12 are detected, and the detected synchronous generator 12 An automatic voltage regulator (AVR) 15 for adjusting the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value based on the output voltage VOUT and a swing signal SVIB described later;
B, and determines whether or not the synchronous generator 12 is operating independently based on the field current signal SIMAG of the synchronous generator 12, and shuts off by the shut-off control signal SOFF when the synchronous generator 12 operates alone. And an islanding operation detection device 41 that shuts off the unit 14.

The automatic voltage regulator 15 is the same as that of the first embodiment shown in FIG. 1, and a detailed description thereof will be omitted. The islanding detection device 41 outputs a vibration signal from a vibration signal generator 30 that outputs a vibration signal SVIB having a predetermined frequency and a field current signal SIMAG corresponding to the field current IMAG that is the output of the automatic voltage regulator 15. A swing amplitude detector 43 for detecting an amplitude of a signal having the same frequency component as that of SVIV and outputting an amplitude detection signal SPP1 having a voltage VPP1 corresponding to the detected amplitude, and a predetermined value of a predetermined field current signal SIMAG. Reference amplitude signal SP having voltage VPREF1 corresponding to amplitude
A reference amplitude setting device 44 for outputting REF1 and an amplitude detection signal S
By comparing the voltage VPP1 of PP1 with the voltage VPREF1 of the reference amplitude signal SPREF1, when the amplitude of a signal having the same frequency component as the fluctuation signal SVIB corresponding to the amplitude detection signal SPP1 is smaller than the amplitude corresponding to the reference amplitude signal SPREF1 ,
That is, when the fluctuation of the reactive power is small, the synchronous generator 1
2 is provided with a comparator 45 that outputs a shutoff control signal SOFF1 so as to determine that the isolated operation is being performed and to shut off the circuit breaker 14.

FIG. 7 shows two detailed structural examples of the fluctuation amplitude detector 43. A first configuration example of the fluctuation amplitude detector 43 is shown in FIG.
As shown in (a), of the field current signal SIMAG, only a predetermined frequency band component corresponding to the same frequency component as the fluctuation signal SVIB is passed, and a band-pass filter 43A that outputs a band-pass signal SBP1; An absolute value detector 43B that performs full-wave rectification of the signal SBP1 and outputs an absolute value signal SABS1, and a fluctuation signal SVI included in the field current signal SIMAG that passes only the low frequency components of the absolute value signal SABS1.
And a low-pass filter 43C that outputs an amplitude detection signal SPP1 having a voltage VPP1 corresponding to the amplitude of a signal having the same frequency component as B.

Next, the operation of the first example of the configuration of the fluctuation amplitude detector 43 will be described. The band pass filter 43A is
Of the field current signal SIMAG, only a predetermined frequency band component corresponding to the same frequency component as the shake signal SVIB is passed,
The bandpass signal SBP1 having the same frequency component as the motion signal SVIB is output to the absolute value detector 43B. The absolute value detector 43B performs full-wave rectification of the bandpass signal SBP1,
The absolute value signal SABS1 is output to the low-pass filter 43C.

As a result, the low-pass filter 43C allows only the low frequency component of the absolute value signal SABS1 proportional to the amplitude of the signal having the same frequency component as the sway signal SVIB to pass, and the signal having the same frequency component as the sway signal SVIB. Is output to the comparator 45 with the amplitude detection signal SPP1 having the voltage VPP1 corresponding to the amplitude of.

On the other hand, in the second configuration example of the fluctuation amplitude detector 43, as shown in FIG. 7B, a Fourier transform of the field current signal SIMAG is performed, and a signal having the same frequency component as the fluctuation signal SVIB is generated. It comprises a Fourier transformer 43D that outputs an amplitude detection signal SPP1 having a voltage VPP1 corresponding to the amplitude. In FIG. 7 (b), for the sake of simplicity, the conversion formula is represented as a = SIMAG A = SPP1.

Next, the operation of the second example of the configuration of the fluctuation amplitude detector 43 will be described. First, the Fourier transformer 43D
Is based on the equations (2) and (3) in FIG.
The field current signal SI has a period T (see FIG. 3) of the fluctuation signal SVIV.
The cosine wave component Ax and the sine wave component Ay are obtained by section integration of MAG. Next, based on the expression (1), an amplitude detection signal SPP1 having a voltage VPP1 corresponding to the amplitude of a signal having the same frequency component as the fluctuation signal SVIB is obtained from the cosine wave component Ax and the sine wave component Ay. Will be output.

Next, the operation of the power generation system 40 will be described. In the initial state, it is assumed that the circuit breaker 14 is in a non-blocking state. The synchronous generator 12 is driven by the prime mover 11 and outputs an output voltage signal SOUT. Thereby, the voltage detector 21 of the automatic voltage regulator 15 generates the detection voltage signal SOUT1 having the voltage VOUT1 proportional to the voltage VOUT of the output voltage signal SOUT, and outputs the detection voltage signal SOUT1 to the adder 22.

The reference voltage setter 20 outputs a reference voltage signal SVREF corresponding to the set reference voltage VREF to the adder 22. On the other hand, the sway signal generator 30 of the islanding detection device 41 outputs the sway signal S having a predetermined frequency.
VIB is output to the adder 22.

Thus, the adder 22 outputs the oscillation signal S
The voltage VOUT1 of the detected voltage signal SOUT1 is subtracted from the added voltage obtained by adding the voltage VVIB of the VIB and the voltage VREF of the reference voltage signal SVREF to obtain a voltage VADD (= VREF + VVIB-VO).
UT1) is output to the deviation amplifier 23.

The deviation amplifier 23 amplifies the voltage VADD of the addition result signal SADD and outputs a deviation amplification signal ASADD to the power amplifier 24. As a result, the power amplifier 24 amplifies the power of the deviation amplification signal ASADD and adjusts the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value, and the output voltage VOUT of the synchronous generator 12 is constant. Is controlled to be the voltage of In parallel with these operations, the oscillation amplitude detector 43 of the islanding operation detection device 41 detects the amplitude of a signal having the same frequency component as the oscillation signal SVIB from the field current signal SIMAG by the configuration shown in FIG. Then, an amplitude detection signal SPP1 having a voltage VPP1 corresponding to the detected amplitude is output to the comparator 45. The reference amplitude setter 44 outputs a reference amplitude signal SPREF1 having a voltage VPREF1 corresponding to a predetermined amplitude to the comparator 45.

As a result, the comparator 45 outputs the voltage VPP1 of the amplitude detection signal SPP1 and the voltage VPRE of the reference amplitude signal SPREF1.
F1 is compared with the swing signal SV corresponding to the amplitude detection signal SPP1.
When the amplitude of the signal having the same frequency component as IB is smaller than the amplitude corresponding to the reference amplitude signal SPREF, the synchronous generator 1
No. 2 determines that an independent operation is being performed. Then, a shutoff control signal SOFF1 is output to shut off the circuit breaker 14, so that the synchronous generator 12 is electrically cut off from the commercial power system 13, and the sending out circuit breaker of the substation is open for work. In such a case, the power generated by the synchronous generator 12 can be reliably prevented from flowing backward,
When the sending-out circuit breaker is closed again, it is possible to prevent the possibility of association due to the power flow being in an asynchronous state.

As described above, according to the third embodiment, based on the field current IMAG of the automatic voltage regulator 15, the synchronization is performed based on the field current fluctuation having the same frequency component as the fluctuation signal SVIB. Since the independent operation state of the generator 12 is detected, the independent operation state of the synchronous generator 12 can be reliably detected without being affected by the frequency fluctuation and the voltage fluctuation of the commercial power system 13. Further, unlike the second conventional example shown in FIG. 11, there is no need to provide a reactive power detector, and the device configuration can be simplified.

Fourth Embodiment FIG. 8 shows a schematic block diagram of a power generation system including an isolated operation detection device for a synchronous generator according to a fourth embodiment. 8, the same parts as those in the third embodiment in FIG. 6 are denoted by the same reference numerals. The power generation system 50 is roughly divided into a prime mover 11 that converts energy such as coal, oil, gas, and the like into mechanical energy to generate a driving force, and is driven by the prime mover 11 and generated by the rotation speed of its rotating shaft. Generator 12 whose frequency is determined, and a shutoff control signal SOF
A circuit breaker 14 for electrically disconnecting the synchronous generator 12 from the commercial power system 13 based on F, a voltage VOUT of the output voltage signal SOUT of the synchronous generator 12 are detected, and the detected synchronous generator 12 An automatic voltage regulator (AVR) 15 for adjusting the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value based on the output voltage VOUT and a swing signal SVIB to be described later, and a swing signal SVIB. The synchronous generator 12 determines whether or not the synchronous generator 12 is performing an isolated operation based on the field voltage signal SVMAG of the synchronous generator 12. Islanding detection device 4 that shuts off
1A.

The automatic voltage regulator 15 is the same as that of the first embodiment shown in FIG. 1, and a detailed description thereof will be omitted. The islanding detection device 41A includes a vibration signal generator 30 that outputs a vibration signal SVIB having a predetermined frequency, and a vibration signal from a field voltage signal SVMAG corresponding to a field voltage VMAG output from the automatic voltage regulator 15. A swing amplitude detector 46 that detects the amplitude of a signal having the same frequency component as that of the signal SVIV and outputs an amplitude detection signal SPP2 having a voltage VPP2 corresponding to the detected amplitude, and a predetermined value of a predetermined field voltage signal SVMAG. A reference amplitude setter 47 for outputting a reference amplitude signal SPREF2 having a voltage VPREF2 corresponding to the amplitude; a voltage VPP2 of the amplitude detection signal SPP2 and a voltage VPRE of the reference amplitude signal SPREF2
By comparing F2, when the amplitude of the signal having the same frequency component as the fluctuation signal SVIB corresponding to the amplitude detection signal SPP2 is smaller than the amplitude corresponding to the reference amplitude signal SPRE1F, that is, when the fluctuation of the reactive power is small. The comparator 48 that determines that the synchronous generator 12 is operating in an isolated manner and outputs a shutoff control signal SOFF1 to shut off the circuit breaker 14
And is provided.

FIG. 9 shows two detailed configuration examples of the fluctuation amplitude detector 46. A first configuration example of the fluctuation amplitude detector 46 is shown in FIG.
As shown in (a), of the field voltage signal SVMAG, only a predetermined frequency band component corresponding to the same frequency component as the fluctuation signal SVIB is passed, and a band-pass filter 46A that outputs a band-pass signal SBP2; An absolute value detector 46B that performs full-wave rectification of the signal SBP2 and outputs an absolute value signal SABS2, and a fluctuation signal SVI included in the field voltage signal SVMAG that passes only the low frequency components of the absolute value signal SABS2.
And a low-pass filter 46C that outputs an amplitude detection signal SPP2 having a voltage VPP2 corresponding to the amplitude of a signal having the same frequency component as B.

Next, the operation of the first example of the configuration of the fluctuation amplitude detector 46 will be described. The band pass filter 46A is
Of the field voltage signal SVMAG, only a predetermined frequency band component corresponding to the same frequency component as the fluctuation signal SVIB is passed,
The bandpass signal SBP2 having the same frequency component as the vibration signal SVIB is output to the absolute value detector 46B. The absolute value detector 46B performs full-wave rectification of the bandpass signal SBP2,
The absolute value signal SABS2 is output to the low-pass filter 46C.

As a result, the low-pass filter 46C allows only the low frequency component of the absolute value signal SABS2 proportional to the amplitude of the signal having the same frequency component as the sway signal SVIB to pass, and the signal having the same frequency component as the sway signal SVIB. The amplitude detection signal SPP2 having the voltage VPP2 corresponding to the amplitude of. On the other hand, the second configuration example of the fluctuation amplitude detector 46 performs a Fourier transform of the field voltage signal SVMAG as shown in FIG.
V corresponding to the amplitude of a signal having the same frequency component as
It comprises a Fourier transformer 46D that outputs an amplitude detection signal SPP2 having PP2.

In FIG. 9B, for the sake of simplicity of the illustration, a conversion formula is represented as a = SVMAG A = SPP2. Next, the swing amplitude detector 46
The operation of the second configuration example will be described. First, the Fourier transformer 46D calculates the equation (2) and the equation (3) in FIG.
Based on the equation, the field voltage signal SVMAG is sectionally integrated with the period T of the fluctuation signal SVIB (see FIG. 3) to obtain a cosine wave component Ax and a sine wave component Ay.

Next, based on the equation (1), the cosine wave component Ax
The amplitude detection signal SPP2 having the voltage VPP2 corresponding to the amplitude of the signal having the same frequency component as the fluctuation signal SVIB is obtained from the sine wave component Ay and output to the comparator 48. Next, the operation of the power generation system 50 will be described.
In the initial state, it is assumed that the circuit breaker 14 is in a non-blocking state. The synchronous generator 12 is driven by the prime mover 11 and outputs an output voltage signal SOUT. Thereby, the voltage detector 21 of the automatic voltage regulator 15 outputs the output voltage signal S
A detection voltage signal SOUT1 having a voltage VOUT1 proportional to the voltage VOUT of OUT is generated and output to the adder 22.

The reference voltage setter 20 outputs a reference voltage signal SVREF corresponding to the set reference voltage VREF to the adder 22. On the other hand, the sway signal generator 30 of the isolated operation detection device 41A outputs a sway signal SVIB having a predetermined frequency to the adder 22. As a result, the adder 22 outputs the voltage VVIB of the swing signal SVIB and the reference voltage signal SVIB.
The voltage VOUT1 of the detected voltage signal SOUT1 is subtracted from the added voltage obtained by adding the voltage VREF of VREF, and the voltage VADD
(= VREF + VVIB-VOUT1)
D is output to the deviation amplifier 23.

The deviation amplifier 23 amplifies the voltage VADD of the addition result signal SADD and outputs a deviation amplification signal ASADD to the power amplifier 24. As a result, the power amplifier 24 amplifies the power of the deviation amplification signal ASADD and adjusts the field current so that the output voltage VOUT of the synchronous generator 12 becomes a predetermined value, and the output voltage VOUT of the synchronous generator 12 is constant. Is controlled to be the voltage of

In parallel with these operations, the swing amplitude detector 46 of the islanding operation detecting device 41A uses the configuration shown in FIG. 9 to change the amplitude of the signal having the same frequency component as the swing signal SVIB from the field voltage signal SVMAG. And outputs an amplitude detection signal SPP2 having a voltage VPP2 corresponding to the detected amplitude to the comparator 48. Further, the reference amplitude setting device 47 outputs a reference amplitude signal SPREF2 having a voltage VPREF2 corresponding to a predetermined amplitude to the comparator 48.

As a result, the comparator 48 outputs the voltage VPP2 of the amplitude detection signal SPP2 and the voltage VPRE of the reference amplitude signal SPREF2.
F2 is compared with the swing signal SV corresponding to the amplitude detection signal SPP2.
When the amplitude of the signal having the same frequency component as IB is smaller than the amplitude corresponding to the reference amplitude signal SPREF, the synchronous generator 1
No. 2 determines that an independent operation is being performed. Then, a shutoff control signal SOFF1 is output to shut off the circuit breaker 14, so that the synchronous generator 12 is electrically cut off from the commercial power system 13, and the sending out circuit breaker of the substation is open for work. In such a case, the power generated by the synchronous generator 12 can be reliably prevented from flowing backward,
When the sending-out circuit breaker is closed again, it is possible to prevent the possibility of association due to the power flow being in an asynchronous state.

As described above, according to the fourth embodiment, based on the field voltage VMAG proportional to the field current of the automatic voltage regulator 15, the field voltage having the same frequency component as the vibration signal SVIB is used. Since the isolated operation state of the synchronous generator 12 is detected based on the voltage fluctuation, the isolated operation state of the synchronous generator 12 is reliably detected without being affected by the frequency fluctuation of the commercial power system 13 or the voltage fluctuation. can do. Further, unlike the second conventional example shown in FIG. 11, there is no need to provide a reactive power detector, and the device configuration can be simplified.

[0101]

According to the first aspect of the present invention, the synchronous generator is set to the isolated operation state based on the amplitude of the same frequency component signal which is the signal having the same frequency component as the fluctuation signal included in the frequency detection signal. Since it is determined whether or not the synchronous generator is present, independent operation of the synchronous generator can be reliably detected without being affected by frequency fluctuation or voltage fluctuation of the commercial power system. According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the same component signal extracting means of the amplitude detecting means converts the same component signal having the same frequency component as the fluctuation signal from the frequency detection signal. The rectifying means performs full-wave rectification of the same component signal and outputs a full-wave rectified signal to low-pass filter means, and the low-pass filter means extracts low-frequency components of the full-wave rectified signal. , The amplitude of the same frequency component signal is detected, so that with a simple configuration, the amplitude of the same frequency component can be reliably detected, and the isolated operation of the synchronous generator can be more reliably detected.

According to the third aspect of the invention, in addition to the effect of the first aspect, the amplitude of the same frequency component signal is detected by Fourier transform of the frequency detection signal. The specifications can be easily changed, and the independent operation of the synchronous generator can be detected with a reliable and optimum configuration.

According to the fourth aspect of the present invention, in addition to the effects of the first to third aspects of the present invention,
The determining means determines that the synchronous generator is in the isolated operation state when the detected amplitude of the same frequency component signal is larger than the predetermined reference amplitude, so that it is easy to determine whether or not the synchronous operation is in the isolated operation state. Thus, the isolated operation state can be reliably determined.

According to the fifth aspect of the present invention, the synchronous generator is in the isolated operation state based on the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal included in the reactive power detection signal. Since it is determined whether or not the isolated operation of the synchronous generator can be reliably detected with a simple configuration.

According to the invention of claim 6, in addition to the function of the invention of claim 5, the same component signal extracting means of the amplitude detecting means has the same frequency component from the reactive power detection signal as the fluctuation signal. The same component signal is extracted, and the rectifying means
The same-component signal extracted by the same-component signal extracting means is subjected to full-wave rectification, and the low-pass filter means detects the amplitude of the same-frequency component signal by passing the low-frequency component of the full-wave rectified signal. With such a configuration, it is possible to reliably detect the amplitude of the same frequency component and more reliably detect the isolated operation of the synchronous generator.

According to the seventh aspect of the present invention, in addition to the operation of the fifth aspect, the Fourier transform detecting means of the amplitude detecting means converts the amplitude of the same frequency component signal by Fourier transform of the reactive power detection signal. Since the detection is performed, it is possible to detect the isolated operation of the synchronous generator with a simple configuration, easily change the specification, and reliably and optimally.

According to the eighth aspect of the invention, in addition to the function of the fifth aspect of the invention,
The determining means determines that the synchronous generator is in the isolated operation state when the detected amplitude of the same frequency component signal is smaller than the predetermined reference amplitude, so that it is easy to determine whether the synchronous generator is in the isolated operation state. Thus, the isolated operation state can be reliably determined.

According to the ninth aspect, it is determined whether or not the synchronous generator is in the isolated operation state based on the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal included in the field current detection signal. And a simple configuration without providing a frequency detection circuit or reactive power detection circuit, etc.
The isolated operation of the synchronous generator can be reliably detected.

According to the tenth aspect, the fifth aspect is provided.
In addition to the effects of the described invention, the same component signal extracting means includes:
The same component signal having the same frequency component as the fluctuation signal is extracted from the field current detection signal, the rectifying means performs full-wave rectification of the same component signal, and the low-pass filter means performs low-frequency component of the full-wave rectified signal. , The amplitude of the same frequency component signal is detected, so that with a simple configuration, the amplitude of the same frequency component can be reliably detected, and the isolated operation of the synchronous generator can be more reliably detected.

According to the eleventh aspect, according to the ninth aspect,
In addition to the effects of the described invention, the amplitude of the same frequency component signal is detected by the Fourier transform of the field current detection signal, so that the configuration is simple, the specification can be easily changed, and the configuration is reliable and optimal. The isolated operation of the synchronous generator can be detected.

According to the twelfth aspect, according to the ninth aspect,
In addition to the effect of the invention according to any one of claims 11 to 11, when the detected amplitude of the same frequency component signal is smaller than a predetermined reference amplitude, the synchronous generator is in an isolated operation state. Therefore, it is easy to determine whether or not the vehicle is in the islanding operation state, and the islanding state can be reliably determined.

According to the thirteenth aspect, it is determined whether or not the synchronous generator is in the isolated operation state based on the amplitude of the same frequency component signal having the same frequency component as the fluctuation signal included in the field voltage detection signal. Therefore, it is possible to reliably detect the independent operation of the synchronous generator with a simple configuration without providing a frequency detection circuit, a reactive power detection circuit, and the like.

According to the fourteenth aspect of the present invention, the first aspect
In addition to the effects of the invention described in the third aspect, the same component signal extracting means extracts the same component signal having the same frequency component as the fluctuation signal from the field voltage detection signal, and the rectifier means full-wave rectification of the same component signal. The low-pass filter means detects the amplitude of the same frequency component signal by passing the low-frequency component of the full-wave rectified signal, so with a simple configuration, reliably detects the amplitude of the same frequency component, The isolated operation of the synchronous generator can be detected more reliably.

According to the fifteenth aspect, the first aspect is provided.
In addition to the effects of the invention described in 3, the amplitude of the same frequency component signal is detected by Fourier transform of the field voltage detection signal, so that the configuration is simple, the specification can be easily changed, and the configuration is reliable and optimal. Thus, the isolated operation of the synchronous generator can be detected.

According to the invention of claim 16, according to claim 1,
In addition to the effect of the invention according to any one of claims 3 to 15, when the detected amplitude of the same frequency component signal is smaller than a predetermined reference amplitude, the synchronous generator sets the synchronous generator to the isolated operation state. Since it is determined that there is, the independent operation state can be easily and reliably determined.

According to the seventeenth aspect, whether or not the synchronous generator is in the isolated operation state is determined based on the amplitude of the same frequency component which is the signal having the same frequency component as the fluctuation signal included in the frequency detection signal. Therefore, independent operation of the synchronous generator can be reliably detected without being affected by frequency fluctuations and voltage fluctuations of the commercial power system.

According to the eighteenth aspect, the same frequency component as the fluctuation signal contained in the reactive power signal is extracted,
Determine whether or not the synchronous generator is in the isolated operation state based on the amplitude of the signal of the frequency component.Detect the isolated operation of the synchronous generator reliably without being affected by the frequency fluctuation or voltage fluctuation of the commercial power system. be able to.

According to the nineteenth aspect, the same frequency component as the fluctuation signal included in the output voltage signal is extracted from the fluctuation frequency component of the field current, and the synchronous power generation is performed based on the amplitude of the signal of the frequency component. Since it is determined whether or not the machine is in the islanding operation state, the islanding operation of the synchronous generator can be reliably detected without being affected by the frequency fluctuation and the voltage fluctuation of the commercial power system.

According to the twentieth aspect, the same frequency component as the fluctuation signal included in the output voltage signal is extracted from the fluctuating frequency component of the field voltage, and the synchronous power generation is performed based on the amplitude of the signal of the frequency component. Since it is determined whether or not the machine is in the islanding operation state, the islanding operation of the synchronous generator can be reliably detected without being affected by the frequency fluctuation and the voltage fluctuation of the commercial power system.

[Brief description of the drawings]

FIG. 1 is a schematic configuration block diagram of a power generation system according to a first embodiment.

FIG. 2 is a detailed configuration block diagram of a fluctuation amplitude detector according to the first embodiment.

FIG. 3 is a diagram illustrating an example of a wobble signal.

FIG. 4 is a schematic configuration block diagram of a power generation system according to a second embodiment.

FIG. 5 is a detailed configuration block diagram of a fluctuation amplitude detector according to a second embodiment.

FIG. 6 is a schematic configuration block diagram of a power generation system according to a third embodiment.

FIG. 7 is a detailed configuration block diagram of a fluctuation amplitude detector according to a third embodiment.

FIG. 8 is a schematic configuration block diagram of a power generation system according to a fourth embodiment.

FIG. 9 is a detailed configuration block diagram of a fluctuation amplitude detector according to a fourth embodiment.

FIG. 10 is an explanatory diagram of a first conventional example.

FIG. 11 is an explanatory diagram of a second conventional example.

[Explanation of symbols]

 Reference Signs List 10 power generation system 11 prime mover 12 synchronous generator 13 commercial power system 14 circuit breaker 15 automatic voltage regulator (AVR) 16, 41, 41A, 61 islanding operation detection device 30 rocking signal generator 31 frequency detector 32, 43, 46, 63 Motion amplitude detectors 32A, 43A, 46A, 63A Band pass filters 32B, 43B, 46B, 63B Absolute value detectors 32C, 43C, 46C, 63C Low pass filters 32D, 43D, 46D, 63D Fourier transformers 33, 44 47, 64 Reference amplitude setting unit 34, 45, 48, 65 Comparator SOUT output voltage signal SIMAG field current signal SVMAG field voltage signal SVIB sway signal SOFF cutoff control signal SFRQ frequency detection signal SREAC reactive power detection signal SPP, SPPO, SPP1, SPP2 Amplitude detection signal SPREF, SPREF0, SPREF1, SPREF2 Reference amplitude signal No. SBP, SBP0, SBP1, SBP2 Bandpass signal

Claims (20)

[Claims] 1. An automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the isolated operation detection device for the synchronous generator, a rocking signal generation for rocking the output voltage, which is a voltage of the output voltage signal of the synchronous generator, by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Means, a frequency detecting means for detecting a frequency of the output voltage signal and outputting a frequency detection signal, and a signal having the same frequency component as the fluctuation signal included in the frequency detection signal based on the frequency detection signal. Amplitude detecting means for extracting a certain frequency component signal and detecting the amplitude of the same frequency component signal; Independent operation detecting apparatus of a synchronous generator characterized by comprising discriminating means for discriminating whether or not said synchronous generator is in the islanding operation state based on the meta reference amplitude, a. 2. The isolated operation detection device for a synchronous generator according to claim 1, wherein the amplitude detection means extracts the same component signal having the same frequency component as the fluctuation signal from the frequency detection signal. Extracting means; rectifying means for performing full-wave rectification of the same component signal to output a full-wave rectified signal; and detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectified signal. An isolated operation detection device for a synchronous generator, comprising: low-pass filter means. 3. An apparatus for detecting an isolated operation of a synchronous generator according to claim 1, wherein said amplitude detecting means performs a Fourier transform of said frequency detection signal to detect an amplitude of said same frequency component signal. An isolated operation detection device for a synchronous generator, characterized by comprising means. 4. The apparatus for detecting an isolated operation of a synchronous generator according to claim 1, wherein the amplitude of the detected same frequency component signal is larger than a predetermined reference amplitude. An isolated operation detection device for a synchronous generator, wherein the synchronous generator is determined to be in an isolated operation state when it is larger. 5. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the isolated operation detection device for the synchronous generator, a rocking signal generation for rocking the output voltage, which is a voltage of the output voltage signal of the synchronous generator, by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Means, a reactive power detection means for detecting a reactive power based on an output voltage and an output current of the synchronous generator, and outputting a reactive power detection signal, included in the reactive power detection signal based on the reactive power detection signal Amplitude detection means for extracting the same frequency component signal, which is a signal having the same frequency component as the fluctuation signal to be detected, and detecting the amplitude of the same frequency component signal; Determining means for determining whether or not the synchronous generator is in an isolated operation state based on the amplitude of the same frequency component signal and a predetermined reference amplitude, wherein the isolated operation of the synchronous generator is provided. Detection device. 6. An apparatus according to claim 5, wherein said amplitude detecting means extracts the same component signal having the same frequency component as said oscillation signal from said reactive power detection signal. Signal extracting means, rectifying means for performing full-wave rectification of the same component signal to output a full-wave rectified signal, and detecting the amplitude of the same frequency component signal by passing a low-frequency component of the full-wave rectified signal And a low-pass filter means. 7. An apparatus for detecting an isolated operation of a synchronous generator according to claim 5, wherein said amplitude detecting means performs a Fourier transform of said reactive power detection signal to detect an amplitude of said same frequency component signal. An isolated operation detection device for a synchronous generator, comprising detection means. 8. The isolated operation detection apparatus for a synchronous generator according to claim 5, wherein the discriminating means is configured such that the detected amplitude of the same frequency component signal is larger than a predetermined reference amplitude. When the synchronous generator is small, it is determined that the synchronous generator is in an isolated operation state. 9. An automatic voltage regulator for adjusting a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that flows backward in generated electric power to a commercial AC power system. In the isolated operation detection device for the synchronous generator, a rocking signal generation for rocking the output voltage, which is a voltage of the output voltage signal of the synchronous generator, by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Means, a field current detection means for detecting the field current and outputting a field current detection signal, and calculating the amplitude of the same frequency component signal having the same frequency component as the rocking signal from the field current detection signal. Amplitude detecting means for detecting, and determining means for determining whether or not the synchronous generator is in an isolated operation state based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude. , Independent operation detecting apparatus of a synchronous generator characterized by comprising a. 10. The isolated operation detection device for a synchronous generator according to claim 9, wherein the amplitude detection means extracts the same component signal having the same frequency component as the fluctuation signal from the field current detection signal. Component signal extracting means, rectifying means for performing full-wave rectification of the same component signal and outputting a full-wave rectified signal, and passing low-frequency components of the full-wave rectified signal to reduce the amplitude of the same frequency component signal. A low-pass filter means for detecting, and an isolated operation detection device for the synchronous generator. 11. An apparatus according to claim 9, wherein said amplitude detecting means performs a Fourier transform of said field current detection signal to detect an amplitude of said same frequency component signal. An isolated operation detection device for a synchronous generator, comprising a conversion detection unit. 12. The apparatus for detecting the isolated operation of a synchronous generator according to claim 9, wherein the amplitude of the detected same frequency component signal is larger than a predetermined reference amplitude. When the synchronous generator is small, it is determined that the synchronous generator is in an isolated operation state. 13. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the isolated operation detection device for the synchronous generator, a rocking signal generation for rocking the output voltage which is a voltage of the output voltage signal of the synchronous generator by outputting a rocking signal having a predetermined frequency to the automatic voltage regulator. Means, a field voltage detecting means for detecting a field voltage corresponding to the field current and outputting a field voltage detection signal; and the same having the same frequency component as the fluctuation signal from the field voltage detection signal. Amplitude detection means for detecting the amplitude of the frequency component signal; and whether or not the synchronous generator is in an isolated operation state based on the detected amplitude of the same frequency component signal and a predetermined reference amplitude. Independent operation detecting apparatus of a synchronous generator characterized by comprising a discriminating means for discriminating. 14. The isolated operation detection device for a synchronous generator according to claim 13, wherein the amplitude detection means extracts the same component signal having the same frequency component as the fluctuation signal from the field voltage detection signal. Component signal extracting means, rectifying means for performing full-wave rectification of the same component signal and outputting a full-wave rectified signal, and passing low-frequency components of the full-wave rectified signal to reduce the amplitude of the same frequency component signal. A low-pass filter means for detecting, and an isolated operation detection device for the synchronous generator. 15. An apparatus for detecting the isolated operation of a synchronous generator according to claim 13, wherein said amplitude detecting means detects the amplitude of said same frequency component signal by performing a Fourier transform of said field current detection signal. An isolated operation detection device for a synchronous generator, comprising a conversion detection unit. 16. An isolated operation detection apparatus for a synchronous generator according to claim 13, wherein said detecting means determines that an amplitude of said detected same frequency component signal is larger than a predetermined reference amplitude. When the synchronous generator is small, it is determined that the synchronous generator is in an isolated operation state. 17. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the method for detecting the isolated operation of a synchronous generator, an output voltage fluctuation that fluctuates the output voltage, which is a voltage of an output voltage signal of the synchronous generator, by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. And a frequency detecting step of detecting a frequency of the output voltage signal; based on the detected frequency of the output voltage signal, extracting the same frequency component as the sway signal included in the output voltage signal; An amplitude detection step of detecting the amplitude of the component signal, and whether the synchronous generator is in an isolated operation state based on the detected signal amplitude and a predetermined reference amplitude. Determination step and, isolated operation detecting method of a synchronous generator characterized by comprising a that determines. 18. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the method for detecting the isolated operation of a synchronous generator, an output voltage fluctuation that fluctuates the output voltage, which is a voltage of an output voltage signal of the synchronous generator, by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. A reactive power detection step of detecting reactive power based on an output voltage and an output current of the synchronous generator, and the same frequency component as the fluctuation signal included in the reactive power signal corresponding to the detected reactive power. An amplitude detection step of extracting and detecting the amplitude of the signal of the frequency component; and operating the synchronous generator independently based on the amplitude of the detected signal and a predetermined reference amplitude. Isolated operation detecting method of the synchronous generator, characterized by comprising: a determination step of determining whether or not the state, the. 19. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the method for detecting the isolated operation of a synchronous generator, an output voltage fluctuation that fluctuates the output voltage, which is a voltage of an output voltage signal of the synchronous generator, by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. A field current detecting step of detecting the field current; and, based on the detected field current, the same frequency as the fluctuation signal included in the output voltage signal from a fluctuating frequency component of the field current. An amplitude detection step of extracting a component and detecting the amplitude of the signal of the frequency component; and operating the synchronous generator in an isolated operation state based on the detected signal amplitude and a predetermined reference amplitude. Isolated operation detecting method of the synchronous generator, characterized in that it and a determination step of determining whether or not the. 20. An automatic voltage regulator that adjusts a field current so that an output voltage becomes a predetermined value is connected, and detects an independent operation state of a synchronous generator that reversely flows generated power to a commercial AC power system. In the method for detecting the isolated operation of a synchronous generator, an output voltage fluctuation that fluctuates the output voltage, which is a voltage of an output voltage signal of the synchronous generator, by outputting a fluctuation signal having a predetermined frequency to the automatic voltage regulator. A field voltage detecting step of detecting a field voltage; and, based on the detected field voltage, a frequency component identical to the fluctuation signal included in the output voltage signal from a fluctuation frequency component of the field voltage. And an amplitude detection step of detecting the amplitude of the signal of the frequency component, and the synchronous generator enters the isolated operation state based on the amplitude of the detected signal and a predetermined reference amplitude. Luke determination step and, isolated operation detecting method of a synchronous generator characterized by comprising a to determine whether.