KR20210014877A - An On-line Monitoring Method and Its Device Using the Circuit Constants Measurement of Electric Power Equipment - Google Patents

Abstract

The present invention relates to a monitoring method for identifying the abnormality and soundness of a large power facility (a power generator, a transformer, a power line or the like) in operation, which is installed in a power plant and a substation of an electric power company or a power receiving room of a factory or the like, and a hardware apparatus therefor. To achieve the purpose, the present invention employs a method of monitoring a facility by measuring an electric circuit integer in the facility, which inevitably changes when the facility is abnormal. In the method, a circuit integer is measured by establishing a primary algebraic equation (including unknown circuit integers) receiving voltages and currents of input and output terminals of a facility and indicating a voltage-current relation of each part in accordance with an equivalent circuit model suitable for the scale of the facility, and analyzing the same. Here, in the case of an equation with two unknown integers, two simultaneous equations are needed (when ″T″ and ″π″ are equivalent), and thus, the equation which has been measured and established on the first step, is stored via a predetermined procedure, and then, is retrieved afterward to be simultaneously used. Since each circuit integer obtained in such way indicates certain physical properties of the facility, when a change is observed, the abnormality of the facility can be predicted and monitored, and the facility can be monitored through its change trend, a graph and a diagram, a message and a warning means.

Description

An On-line Monitoring Method and Its Device Using the Circuit Constants Measurement of Electric Power Equipment {An On-line Monitoring Method and Its Device Using the Circuit Constants Measurement of Electric Power Equipment}

The present invention relates to a technical method and a hardware device for a monitoring method that enables safe operation and avoids or prevents accidents by checking the abnormality and soundness of a power facility that is constantly operating by applying a voltage.

, 용량성리액턴스

, 누설저항

)의 변화에 의하여 비롯된다. 그러나 지금까지는 운전중인 전력설비의 회로정수를 측정하는 방법은 없었고 전력설비에 센서들을 부착하여 설비의 회로정수 변화로부터 발생된 2차적인 물리현상인 설비의 온도, 압력, 진동, 특정 가스 발생 및 부분방전 현상 등을 감지하여 전력설비의 상태를 예측하여 운전해오고 있는 실정이며, 이윽고 사고상태에 이르면 과전류나 전압, 차전류 등의 확대된 현상을 검출하는 보호계전장치 등을 이용하여 전력기기를 긴급 정지시키거나 경보를 발생하여 알려 주는 운전제어 방식을 사용한다.The presence or absence of an abnormality in the power facility or change of state is primarily related to the internal circuit constants (resistance r , inductive reactance

, Capacitive reactance

, Leakage resistance

). However, until now, there was no way to measure the circuit constant of the power facility in operation, and by attaching sensors to the power facility, the secondary physical phenomena arising from the change in the circuit constant of the facility, such as temperature, pressure, vibration, and specific gas generation and parts. Power equipment is being operated by predicting the state of power equipment by detecting discharge phenomena. In the event of an accident, the power equipment is emergency by using a protection relay device that detects enlarged phenomena such as overcurrent, voltage, and differential current. Use the operation control method to stop or generate an alarm to notify you.

For example, in the case of monitoring by temperature, it does not detect temperature in all parts of the facility, but only detects overheating or temperature change in the area where the temperature sensor is installed, and there are areas that cannot be detected or there is a time delay in detecting abnormalities There is a lack of detection and monitoring methods for abnormalities such as possible, and even more so at the beginning of the accident. In particular, in the case of a transmission line installed in a large space, a number of sensors must be installed and there is a lot of difficulty in maintaining them, so existing monitoring methods are less practical.

The preceding patent (refer to the preceding patent document) pursues the same purpose, but it is a method mainly targeting transmission lines, requiring a complex analysis process through a two-step calculation process, and considering the equivalent electric circuit for the facility as a left-right symmetry. It gives measurement results that are not suitable for generators or transformers that are not.

), 절연체의 누전이나 절연 열화 등에 대하여는 누설저항(

) 및 용량성 리액턴스(

))의 값들이 설비의 여러가지 상태를 나타내주고 있음에 착안한 방법으로 감시효과와 실용성이 높은 새로운 방법으로 고가의 주요설비 상태감시에 적합하다.However, the method of this proposal is applied to the circuit resistance ( r) for the condition of each conductor, the condition of the connection and the contact terminal connecting the equipment, the faulty condition of the contact part of the circuit breaker and switchgear. ), inductive reactance (

), leakage resistance (

) And capacitive reactance (

This is a new method with high monitoring effect and practicality as a method conceived that the values of )) indicate various conditions of equipment, and is suitable for monitoring the condition of expensive main equipment.

Domestic Patent Registration No. 10-1171027-0000 (2012.05.05.) (The target facilities and functions of the patent are similar, but the method and device are different)

The latest transmission and distribution engineering 1999. 2. Song Gil-young, Ph.D., Engineering, ISBN 89-381-0198-3 Identical Publishing House

In the present invention, the internal circuit constants of the facility must be measured in order to monitor the presence or integrity of the power facility being operated. A conventional method is a range relay that measures the impedance of the circuit, but this range relay is only the impedance of the power facility. In addition, it is not possible to measure the circuit constant of its own by measuring both the system and load side impedances. There is a method to measure by installing two impedance relays at the input and output terminals and calculating the difference value of the measured impedance at the same time. Since integers are connected in series and parallel, it is difficult to accurately calculate each integer.

In order to measure the internal electric circuit constant of the power facility, a hardware device (1) centered on a microprocessor is connected to the power facility as shown in [Fig. 1], and the voltage from the voltage transformers (2) and current transformers (3), It receives the current, calculates and measures the electric circuit constant by a predetermined software method, and determines and monitors the state of the facility according to the degree of change of the values.

The actual internal electric circuit of the power facility is very complex, but in order to analyze the electrical characteristics, equivalent circuit models suitable for each facility are used. In the present invention, equivalent circuit models for generators, transformers, and transmission lines are adapted to suit the size and type of equipment [ 2], [Fig.-3] and [Fig.-4] are selected in three forms, and the measured instantaneous voltage and currents measured from the input and output terminals of the equipment are received, and a predetermined digital operation method is used. Calculate the size of his waste loss (complex number), establish two to three circuit equations (first-order equations) suitable for the model circuit, and analyze these equations to measure the electric circuit constants representing the equipment state.

Here, the unknown circuit constant is calculated immediately from the equation with one unknown, and in the case of the equation with two unknown circuit constants, ±5% or more of the currently measured voltage and current among the same equations measured and stored previously. A total of two first-order system equations are constructed by searching for differences (the ones with differences in the output of the facility), and two unknown circuit constants are calculated from them.

This method is characterized by a method of comparing and reviewing the change in the calculated and measured circuit constant, and if the change increases or decreases by more than a certain value, it is judged as an abnormality or defectiveness of the facility and monitored so that an appropriate response is possible.

)를 가진 회로로 모델링하므로써 실제의 상세한 회로정수를 측정하는데 부적당하고 복잡한 수학함수 처리나 여러번의 연산처리가 필요함에 비하여 본 발명에서는 2개의 연립 1차방정식을 푸는 것만으로도 다양한 회로정수를 구할 수 있다.For the same purpose, the method according to the preceding patent is a 4-terminal constant (

), it is inappropriate to measure actual detailed circuit constants and requires complex mathematical function processing or computational processing several times, but in the present invention, various circuit constants can be obtained simply by solving two simultaneous linear equations. have.

, 누설저항:

, 병열리액턴스:

등)과 이들로부터 절연상태를 알 수 있는 유전정접(tanδ)을 정략적으로 측정하여 운전 중에 그의 변화를 감시함으로써 사고가 크게 진전되기 이전에 전력설비의 이상유무 상태를 더 신속하고 정확하게 감시할 수 있어 지금까지의 기술적 방법보다 우수한 결과를 기대 할 수 있다. 이로써 설비 이용률 향상 및 수명연장에 크게 이바지 하여 전력회사들과 전기사용자들의 전력설비 운용성과 전력공급신뢰도 향상에 큰 도움을 기대할 수 있다.The present invention is an electric circuit constants that inevitably change when an abnormal phenomenon occurs in a power facility (direct heat resistance: r , direct heat reactance:

, Leakage resistance:

, Parallel reactance:

Etc.) and the dielectric loss tangent (tan δ ) that can be used to determine the insulation status from them, and by monitoring the change during operation, it is possible to more quickly and accurately monitor the abnormality status of the power facility before the accident progresses significantly. So, you can expect better results than the previous technical methods. This greatly contributes to improving the facility utilization rate and prolonging the lifespan, and can be expected to greatly help power companies and electric users to improve power facility operability and power supply reliability.

[Fig. 1] A connection diagram in which the condition monitoring device according to the present invention is used in connection with the monitored power facility.
2 is a block diagram showing the internal structure and function of a state monitoring device according to the present invention.
[Fig. 3] Equipment voltage, capacity It is a "T" type equivalent circuit diagram for applying the principles of the present invention, and corresponds to small and medium capacity, short distance (voltage 70kV, capacity 50MVA or more) equipment.
[Fig. 4] It is a "π"-type equivalent circuit diagram for applying the principles of the present invention, and corresponds to medium and large capacity, medium and long distance equipment (voltage 200kV, capacity 350MVA or more) equipment.
[Fig. 5] It is an equivalent circuit diagram of "a" type for applying the principles of the present invention, and corresponds to other small scale facilities.
[Fig. 6] is a flow chart showing a procedure in which the present invention is implemented.
[Explanation of code]
1: Power facility condition monitoring device
2: Voltage transformers that reduce the high voltage of the input and output side of the facility to low voltage
3: Current transformers that reduce high voltage and high current to the level of 1 to 5 amps
4: voltage input module
5: current input module
6: A module that accepts environmental information (temperature, weather conditions, etc.)
7: A/D conversion module that converts analog information into digital form
8: GPS receiving module required to achieve time synchronization
9: module that stores digitized information in memory
10: operation processing device
11: HMI module
12: interface module
13; Data storage module
14: power supply module

With reference to the accompanying drawings, a detailed description will be given of a method for monitoring the state of power facilities by measuring circuit constants during operation according to the present invention.

Input and output voltage and current normal value calculation and storage

The state monitoring device (1) receives three-phase voltage and current from the voltage transformer (2) and current transformer (3) installed in the power facility at the same time, and is input to the voltage input module (4) and the current input module (5). After a noise reduction process through signal adjustment and filtering, the AD conversion module 7 is sequentially converted to digital data, and then sent to the storage module 13 through the data processing module and waited. If necessary, the operation processing module 10 ), and each voltage and current values are obtained in complex form through the computational processing of the Fourier transform process. The voltage and current obtained at this time are expressed as [Number 1] and [Number 2], respectively, for convenience. These values are once sent to the data storage module 13 to be stored and used in a later process.

[Wed 1]

: 1차측 A상 전압(복소수값:phasor value)),here

: Primary A-phase voltage (complex value: phasor value)),

: 1치측 A상 전압의 실효값(real value)

: Real value of A-phase voltage on the 1-value side

: 1차측 A상 전압의 허수값(imaginary value)

: Imaginary value of the primary A-phase voltage

: 2차측 A상 전압(복소수값: phasor value)),

: Secondary A-phase voltage (complex value: phasor value)),

: 2치측 A상 전압의 실효값(real value)

: Real value of A-phase voltage on the binary side

: 2차측 A상 전압의 허수값(imaginary value)

: Imaginary value of the secondary side A-phase voltage

Hereinafter, voltages of other phases (B-phase, C-phase) have the same type of symbol, and each notation is omitted.

[Wed 2]

: 1차측 A상 전류(페이저값: phasor value)),here

: Primary A-phase current (phasor value)),

: 1치측 A상 전류의 실효값(real value)

: Real value of the 1-value side A-phase current

: 1차측 A상 전류의 허수값(imaginary value)

: Imaginary value of the primary A-phase current

: 2차측 A상 전류(페이저값: phasor value)),

: Secondary A-phase current (phasor value)),

: 2치측 A상 전류의 실효값(real value)

: Real value of the A-phase current on the binary side

: 2차측 A상 전류의 허수값(imaginary value)

: Imaginary value of the secondary side A-phase current

Hereinafter, other phase (B-phase, C-phase) currents are marked with the same type of symbol, and each notation is omitted.

Calculation and storage of pure normal voltage and current (refer to non-patent literature)

Then, by calculating the video component or reverse phase voltage and current of the three-phase system that may cause an error in the measurement of the circuit constant, subtracting from each phase voltage and current value obtained previously removes the video component and the reverse phase component, respectively, to measure the circuit constant. There is a need for a process to minimize errors. Here, the process of calculating the image component or the reverse phase component and the process of subtracting the image and reverse phase components from each phase voltage and current obtained in [Number 1] and [Number 2] to obtain a pure normal component Since the method shown can be applied as it is, the description will be omitted in this specification. From then on, the voltage and current values of each phase obtained from [Number 1] and [Number 2] are already pure image, inverse phase, harmonic, and high-frequency components have been removed. It is regarded as obtained by the normal value

Adoption of equipment equivalent circuit model

"형 단순등가회로를 적용하여 설비 내부의 전기회로정수를 산출하도록 한다. 등가회로는 각상이 동일하므로 단지 "A"상에 대하여만 나타내었다.Next, three equivalent circuit models are set and introduced in order to calculate the internal circuit constant of the power facility. In general, power facilities such as generators, transformers, and transmission lines adopt and use equivalent circuits that can display their electrical characteristics most closely to the actual, depending on the scale. In the present invention, as described above, for small and medium-sized, short-distance equipment (voltage 70kV or higher or capacity 50MVA or higher), it is a "T"-type equivalent circuit as shown in [Fig. ) Is a "π"-type equivalent circuit as shown in [Fig. 4], and for smaller facilities less than that, it is shown in [Fig. 5].

Apply "type simple equivalent circuit to calculate the electric circuit constant inside the facility. Since each phase of the equivalent circuit is the same, only the "A" phase is shown.

[Example 1]

The method of measuring the circuit constant of small and medium-sized power equipment (voltage 70kV or higher or capacity 50MVA or higher) using "T" type equivalent circuit will be described.

구하기1) Series circuit constant

exoneration

)의 양단에 나타나는 전압, 전류에 관한 전기회로이론을 방정식으로 표현하면 다음 수식 [수 3] [수 4] [수 5] 들과 같다. 여기서 실제로 전력설비들은 3상 회로이지만 각상이 동일한 형태이므로 대표적으로 a상에 대하여만 수식을 표기하였다.In the equivalent circuit of [Fig. 3], each impedance (

If the electric circuit theory about voltage and current appearing at both ends of) is expressed as an equation, it is as follows: [Number 3] [Number 4] [Number 5]. Here, the power facilities are actually three-phase circuits, but since each phase is of the same type, the formula is represented only for phase a.

[Wed 3]

here

: 입력단측 a상 직열임피던스(

)

: A-phase direct thermal impedance on the input side (

)

: 입력단 a상 전압

: Input terminal a-phase voltage

: 중간점 a상 전압

: Mid-point a-phase voltage

: 입력단 a상 전류

: Input terminal a-phase current

[Wed 4]

here

: 출력단측 a상 직열임피던스(

)

: Output a-phase direct thermal impedance (

)

: 출력단 a상 전압

: Output a-phase voltage

: 중간점 a상 전압

: Mid-point a-phase voltage

: 출력단 a상 전류

: Output a-phase current

[Wed 5]

here

: 중간점 a상 전압

: Mid-point a-phase voltage

: 설비내부 a상 병렬임피던스

: A-phase parallel impedance inside the facility

: 입력단 a상 전압

: Input terminal a-phase voltage

: 출력단 a상 전류

: Output a-phase current

를 산출하기 위하여 [수 5] 의

를 [수 3] 및 [수 4] 에 각각 대입하고 이들을 종합적으로 정리하면 아래 [수 6] 식과 같이 된다.Unknown essence

To calculate [number 5] of

Substituting in [Equation 3] and [Equation 4] respectively, and summarizing them collectively, it is as shown in [Equation 6] below.

[Wed 6]

는 측정된 값으로 기지수이고

2개는 구하고자 하는 미지수이다. 따라서 이 2개의 미지수를 산출(측정)하기 위하여는 또 다른 운전조건(전압,전류가 다른)에서 수립된 [수 6] 과 같은 형태의 1차 방정식이 1개 이상 더 필요하다. 따라서 앞서 측정되고 방정식으로 수립되어 저장된 [수 6] 형태의 다른 방정식 중 출력단 전압, 전류 값(

)이 현재 것과 일정치 이상 차이(예 ±5%이상)가 있는 것 중 차이가 크고 기타 운전환경(외기 온도 등)은 현재와 유사한 경우를 검색하여 2개의 1차 연립방정식을 구성하고 이로부터 미지의 회로정수를

를 구한다. 따라서 매번 측정하여 수립되는 [수 6] 형태의 방정식은 저장하는 것은 원칙으로 하되 이미 저장된 방정식의 전압, 전류의 크기와 위상각이 각각 ±5%이상 차이가 나는 것들을 저장하여 이후과정에서 필요에 따라 선택 사용 할 수 있도록 해야 한다. 다만 2일 이상 오래 저장된 방정식은 자동으로 삭제 되도록 하여 오래된 데이터로부터 오차 발생이 생기지 않도록 한다. 아울러 설비 별 현장별 여건에 따라 적합하게 이들의 크기 레벨을 수동으로 조정 할 수 있도록 장치를 설계 제작한다.Four state variables in [Number 6] above

Is the measured value and is known

Two are the unknowns you want to find. Therefore, in order to calculate (measure) these two unknowns, one or more linear equations in the form of [Number 6] established under another operating condition (different voltage and current) are required. Therefore, among other equations in the form of [Number 6] previously measured and established and stored as an equation, the output voltage and current values (

) Is larger than the current one (e.g. ±5% or more), the difference is large, and other operating environments (external temperature, etc.) are similar to the current one, and two first-order systems of equations are formed and unknown therefrom. The circuit constant of

Find Therefore, it is a principle to store equations in the form of [Number 6], which are measured and established each time, but store those that have a difference of ±5% or more, respectively, in the voltage, current magnitude, and phase angle of the previously stored equation. It should be made available for selection. However, the equations stored longer than two days are automatically deleted so that errors do not occur from the old data. In addition, devices are designed and manufactured so that their size levels can be manually adjusted according to the conditions of each site.

구하기2) Internal parallel circuit constant

exoneration

)를 산출하기 위하여는 중간점 전압

을 알아야 하므로 식 [수 7] 을 이용하고 이어서 전압, 전류간의 관계에 따라 식 [수 8] 과 같이 연산하여 산출 한다. 여기서 설비가 변압기나 리액터가 아닌 경우는

성분은 존재하지 않아 생략된다.Admittance constituting the internal circuit constant of the facility (

) To calculate the midpoint voltage

Since you need to know Eq. [Equation 7], then calculate it as Equation [Equation 8] according to the relationship between voltage and current. Here, if the facility is not a transformer or reactor,

Ingredients do not exist and are omitted.

[Wed 7]

을 산출한 후 식 [수 5]

로부터

After calculating the equation [Equation 5]

from

[Wed 8]

) 성분과 리액턴스 성분인 정전용량(

)과 유도성 성분(

:변압기, 리액터의 경우만 존재) 측정이 가능하며 그들의 변화에 따라 설비에 이상을 예측 할 수 있게 된다.In this way, the leakage resistance and the iron loss resistance forming the parallel circuit are combined (

) Component and reactance component (

) And inducible components (

: Only in the case of transformers and reactors) Measurement is possible, and abnormalities in the facility can be predicted according to their changes.

[Example 2]

Calculation of the constant of medium and large-capacity power equipment (voltage 200kV or higher or capacity 350MVA or higher) using "π" type equivalent circuit

1) Internal parallel circuit constant calculation

구하기

exoneration

성분은 존재하지 않는다.In the equivalent circuit diagram [Fig. 4], if the current relationship at the left and right branch points of the π circuit is expressed by an equation, [number 9] is established. In the case of a non-transformer or reactor,

There are no ingredients.

[Wed 9]

)을 도입하여 회로의 전압-전류간의 관계를 1차 회로방정식으로 나타내면 [수 10] 으로 표현된다.The voltage across both ends (

) Is introduced and the relationship between voltage and current of a circuit is expressed as a first-order circuit equation, expressed as [number 10].

[Wed 10]

를 구한다. (이 부분에서 앞의 "T"형 등가회로에서와 동일한 처리가 필요하다.)Here, again, [Number 10] is a linear equation with four known (measured values) and two unknowns. As in the previous "T" model, two simultaneous equations are required. We need an equation of the form [number 10] under conditions. On the other hand, as in the "T" type above, an unknown circuit constant from two systems of equations is selected by selecting the one with a large difference among the previous equations stored in the previous step.

Find (In this part, the same processing as in the previous " T " type equivalent circuit is required.)

구하기2) Series circuit constant

exoneration

를 구하고, 두지점간의 전압강하 식 [수 12] 으로 부터 회로정수

을 구한다.Current at the first branch point from the equation [Number 11] for voltage and current established at both branch points in [Fig. 4]

And the circuit constant from the voltage drop equation [Equation 12] between the two points

Find

[Wed 11]

[Wed 12]

[Example 3]

"형 등가회로: 소용량 전력설비(전압 70kV이하, 용량50MVA미만)회로 정수 산출 방법을 설명한다"

"Type equivalent circuit: Explains how to calculate the constants of small-capacity power equipment (voltage 70kV or less, capacity 50MVA or less)

구하기1) Internal parallel circuit constant

exoneration

회로 분기점 전압

은 출력측 전압

과 같으며 따라서 바로 [수 13] 를 통하여 병렬회로의 회로정수

를 구할 수 있다. (역시 변압기나 리액터가 아닌 경우

성분은 존재하지 않음.)[Fig. 5] In the equivalent circuit

Circuit breakout voltage

Is the output side voltage

And thus the circuit constant of the parallel circuit through [Number 13]

Can be obtained. (If it is not a transformer or reactor again

Ingredients are not present.)

[Wed 13]

구하기2) Series circuit constant

exoneration

)를 이에 흐르는 전류 (

)로 나누는 전압, 전류방정식 [수 14] 을 이용하여 구한다.As can be seen from [Fig. 5], the voltage difference between both ends (

) To the current flowing through it (

It is calculated using the voltage and current equation [Number 14] divided by ).

[Wed 14]

[Example 4]

A method of monitoring the calculation of the dielectric loss tangent (tan δ ) representing the insulation state of power facilities will be described.

Dielectric loss tangent (tan δ _a) is defined as [Number 15] to indicate the insulation state of general electrical equipment or transmission lines (especially underground cable lines). : Phase a) is used, and to measure this, measure by using a test device in which a separate voltage application device and a current measuring device are combined while the power facility is stopped.

[Wed 15]

: 설비의 절연부분(가압된 a상 회로와 대지사이)에 존재하는 정전용량 (

)here

: Capacitance present in the insulating part of the facility (between the pressurized phase a circuit and the earth) (

)

: 설비의 절연부분(가압된 a상회로와 대지사이)을 통하여 누전되는 일종의 사고성 전기 저항값(=

)

: A kind of accidental electrical resistance value that is shorted through the insulation part of the facility (between the pressurized phase a circuit and the earth) (=

)

There is a 90° difference in phase angle between the current due to the capacitance ( C _a ) and the current to be shorted, so even if the leakage current increases, the value of tan δ _a increases to _a large value, making it easy to identify the insulation state. Measurement is being used. Accordingly, in the present invention, the dielectric loss tangent is calculated by the following method using the previously calculated and measured circuit constant, and is used for facility condition monitoring. In the case of a transformer or a reactor, the capacitance or leakage resistance values measured in the present invention are combined with the excitation circuit, so it is different from the pure value for the insulator, but it is a qusi-tan δ _a value indicating the insulation state. It is useful for monitoring the insulation state during equipment operation.

The following describes the method of calculating the dielectric loss tangent (tan δ _a ) in the power facility indicated by the three equivalent circuits presented above.

1) Explain the case of generators and transmission lines.

)로 표시되는 부분은 실제로 없는 부분으로서 나머지 저항 성분(

)과 정전용량(

) 성분회로만이 존재하며 이에 흐르는 전류들("T" 및 "

"등가회로의 경우

, "π" 등가회로의 경우 (

)을 각각 산출한 후 해당 분기점 전압(

또는

및

)을 도입한 식 [수 15] 및 [수 16] 을 이용하여 각각의 실수 저항성분(

)과 허수 정전용량(

) 성분 구함으로써 각각의 tanδ _a 를 산출 할 수 있다.The generator or transmission line is the inductance of the parallel circuit in the three equivalent circuits ([Fig. 3] to [Fig. 5])

The part indicated by) is the part that is not actually present and the remaining resistance component (

) And capacitance (

) Only the component circuit exists and the currents flowing through it ("T" and "

"In the case of an equivalent circuit

, In the case of "π" equivalent circuit (

) After each calculation, the corresponding branch voltage (

or

And

) Using equations [Equation 15] and [Equation 16], each real resistance component (

) And imaginary capacitance (

) Each tan δ _a can be calculated by obtaining the component.

"등가회로의 경우[Number 15]: "T" and "

"In the case of an equivalent circuit

[Number 16]: In the case of "π" equivalent circuit

2) Describe the case of transformers and reactors.

) 성분과 철심의 철손저항(

)성분이 각각 용량성 리액턴스(

) 및 누설저항(

)에 병열로 합성되어 나타나므로 앞 단계에서 산출 측정한 회로정수 값에서 이들 성분을 분해시킨(병열회로 해석에 의해 배제시킨) 값을 산출하여야 한다. 여기서 변압기나 리액터가 가지는 철손저항(

) 값과 여자리액턴스 (

) 값은 주로 설계제작에 의해 정해지는 값들로써 개발시험이나 규격승인시험 또는 준공시험 결과 등을 통하여 얻을 수 있는 바 이 값들을 본 장치에 입력시켜 필요로 하는 용량성 리액턴스(

) 및 누설저항(

) 산출시 사용한다.The equivalent circuit for this facility corresponds to [Fig. 3] or [Fig. 4], and the difference from the previous generator and transmission line is the reactance (

) Component and iron loss resistance of iron core (

) Each component has a capacitive reactance (

) And leakage resistance (

), it is synthesized and displayed in parallel, so the values obtained by decomposing these components (excluded by parallel circuit analysis) from the circuit constant values calculated and measured in the previous step must be calculated. Here, the iron loss resistance of the transformer or reactor (

) Value and excitation reactance (

) Values are values determined mainly by design and manufacture, and can be obtained through development tests, standard approval tests, or completion test results, etc. These values are entered into the device and required capacitive reactance (

) And leakage resistance (

) Used when calculating.

)에는 철손저항(

) 과 누설저항(

)이 병렬연결 되어 나타나므로 구하고자 하는 미지의 누설저항(

)은 측정된 병렬회로 전체의 임피던스중 실수부(Real Part)에서 병렬 연결된 철손저항(

)을 배제시키는 회로방정식 [식 17] 으로 산출할 수 있다.This part will be described in more detail through [Fig. 6]. If the parallel circuit part of the equivalent circuit is shown in detail, the resistance component (

) Is the iron loss resistance (

) And leakage resistance (

) Is displayed in parallel, so the unknown leakage resistance (

) Is the iron loss resistance connected in parallel at the real part of the measured impedance of the entire parallel circuit (

) Can be calculated by the circuit equation [Equation 17] that excludes.

[Equation 17]

)을 감산하면 순수한 정전용량을 내포한 용량성 리액턴스 값(

)을 얻을 수 있으며 식으로 표시하면 [식 18] 과 같다.In addition, for the reactance part of the parallel circuit, in the same way as the resistance component, the excitation reactance value of the transformer in the imaginary part (

) Is subtracted, the capacitive reactance value with pure capacitance (

) Can be obtained and expressed as an equation as in [Equation 18].

[Equation 18]

) 과 용량성리액턴스 (

) 값으로 부터 유전정접(tanδ _a )을 산출 할 수 있고 그 크기의 변화시 이상 유무를 감시할 수 있게 된다. 변압기 및 리액터에 관한 유전정접은 회로 구조상 엄밀한 의미의 유전정접이 아닌 준 유전정접(Quasi tanδ _a )에 해당되지만 절연 불량 상태로 되면 이 값에도 변화가 발생하여 상태감시에 유용하게 된다.Leakage resistance obtained in this way (

) And capacitive reactance (

) From the value, the dielectric loss tangent (tan δ _a ) can be calculated, and when the size is changed, the presence or absence of an abnormality can be monitored. Dielectric loss tangent for transformers and reactors corresponds to quasi tan δ _a , not dielectric loss tangent in the strict sense of the circuit structure, but when insulation becomes defective, this value also changes, making it useful for monitoring the state.

[Example 5]

Describes the method of determining whether there is an abnormality for monitoring the state of power facilities.

When an abnormality occurs inside the power facility, some or many of the values of the circuit constants and dielectric loss tangent (tan δ ) calculated through the above embodiments inevitably change. These values are determined through this method and apparatus. It is possible to monitor and grasp the health and operation status of the power facility by providing the facility status by comparing and analyzing their changes by measuring during regular operation.

When the method and apparatus of the present invention is applied, accidents can be prevented in advance by detecting even a small amount of state change in the past facility operation method, which was operated without knowing, even if the usual operation condition is getting worse. The invention is of great value.

Describes the phenomenon measured when the circuit connection of the facility and the connection part are defective.

)이나, 저항 성분(r,r ₁,r ₂)이 증가 된다면 그 전력설비의 주 회로를 구성하는 권선이나 도체 접속부, 차단기 또는 스위치류의 접속 내지 접촉부, 변압기의 경우 부하시 탭절환기 등의 접촉부, 송전선의 경우는 전선이나 케이블 접속부 등의 전기적인 접속상태 불량으로 판단할 수 있다. 접속 상태가 불량하면 초기에는 국부과열을 일으키지만 지속되면 접속부의 저항이 증가되어 과열이 심화되고 점차 넓은 범위의 과열로 진전되어 이윽고 대형사고로 확대 될 수 있다.The absolute value of the series circuit constant of each model circuit [Fig. 3] [Fig. 4] [Fig. 5] while the power facility is operating (

), or if the resistance component ( r , r ₁ , r ₂ ) increases, the winding or conductor connection part of the main circuit of the power facility, the connection or contact part of a circuit breaker or switch, and in the case of a transformer, a contact part such as an on-load tap-changer In the case of transmission lines, it can be judged as poor electrical connection conditions such as wires or cable connections. If the connection is poor, local overheating occurs initially, but if it persists, the resistance of the connection is increased, which intensifies the overheating and gradually progresses to a wide range of overheating, which may eventually lead to a major accident.

Describes the phenomenon measured when the equipment's internal circuit and insulator insulation is defective.

)이나, 리액턴스(

또는

) 값들 및 유전정접(tanδ _a ) 값에 변화가 나타나게 된다. 이들에 대한 변화량과 당시의 부하 운전 조건 및 설비의 기타 일반적인 운전조건(온도, 압력, 외기 상태 등)를 종합 고려하여 설비상태를 표시 또는 제시할 수 있으며, 이로부터 운전, 유지보수 전략이나 방향을 정하여 중요한 고가의 전력설비 자산관리 및 전력회사 경영을 크게 개선 할 수 있게 된다.When the performance of the power facility insulator is deteriorated or a partial short circuit occurs, the leakage resistance (

) Or reactance (

or

) Values and the dielectric loss tangent (tan δ _a ). It is possible to display or present the facility status by comprehensively considering the amount of change, the load operating condition at the time, and other general operating conditions of the facility (temperature, pressure, outside air condition, etc.), from which operation and maintenance strategies or directions can be determined. It will be able to significantly improve the asset management of important expensive power facilities and power company management.

In detail, considering that the electrical circuit configuration or physical configuration differs depending on the type of power facility, the state can be monitored by applying the detailed method as shown in [Table 1] below. In particular, in this part, it is considered to be very effective if the artificial intelligence technique is applied to the decision-making process in which the experience and knowledge of experts in the fields of design, manufacturing, operation, maintenance, and repair of each power facility are combined to determine countermeasures.

4) Describe the overall procedure for monitoring the state of power facilities during operation.

A block diagram of the methods and procedures described so far is shown in Fig. 7.

The system for monitoring the state of the power facility by measuring the change in the circuit constant of the power facility according to the present invention receives input and output voltages and currents from the monitored power facility, and then removes the image and the reverse phase to reduce the measurement error, and simultaneously harmonics and By removing high-frequency components and selecting an equivalent circuit model suitable for the facility, an electric circuit equation (2~3 linear equations) consisting of voltage, current and circuit constants is formed.

At this time, for the equation with two unknowns, the output, voltage, and current values among the previously stored equations are searched for more than ±5% from the current one, and the two system of equations are formed to calculate the unknown circuit constant and measure the value.

Subsequently, the present invention monitors the change of the measured circuit constants, and if the change is more than a predetermined value or the change continues, the expected facility abnormality or defects are presented through a graph or message using the HMI according to the method described above. It can guide necessary measures or automatically shut off and stop the facility.

Here, when an equation with two unknowns is established when establishing an equation, it is necessary to store the equation in order to obtain the unknown in parallel with the equation with two unknowns established at another moment.

In the present invention, errors that appear when measuring circuit constants are errors that occur in voltage and current transformers and errors that occur in devices and calculations. These are almost constant levels. This state monitoring does not use the true values of the constants, but changes in the measured values. It is not a special problem as monitoring the state of the power equipment for the target.

)와 절연상태 지수인 유전정접(Tanδ)등을 운전 중에 측정 할 수 있는 방법과 장치를 개발 적용함으로써 전력설비의 이상 유무 상태를 실시간으로 파악하여 고가의 중요 설비가 사고에 이르기 전에 조치 할 수 있도록 자동 감시하는 새로운 고안이다. 이를 위한 측정방법이나 변화 감지 방법은 현재의 일반적인 디지털 기술 및 소프트웨어로 어렵지 않게 구현이 가능하며 현재 사용중인 전압, 전류 변성기와 기타 센서들로 부터 필요한 입력을 받아들일 수 있어 현실 산업현장에서 용이하게 이용이 가능하고 설비 안전 및 장수명화 등에 기여 할 새로운 고안이다.The present invention is attached to power facilities such as generators, transformers, and transmission lines installed in power generation substations or places where electricity is used, and the circuit constant (

) And dielectric loss tangent ( Tanδ ), which is an insulation state index, during operation, by developing and applying a method and device to determine the abnormality of power facilities in real time and take action before an accident occurs. It is a new device for automatic monitoring. The measurement method or change detection method for this can be implemented without difficulty with the current general digital technology and software, and it can be easily used in the actual industrial field as it can accept the required input from the voltage, current transformer and other sensors currently in use. This is a new design that will make this possible and contribute to facility safety and long life.

Claims (5)

The first order algebraic equations of an equivalent electric circuit consisting of electric circuit constants representing the characteristics of the equipment by receiving the voltages and currents of the input and output terminals from the power equipment (generator, transformer, transmission line, etc.) being operated under pressure. The steps to establish,
Calculating and measuring circuit constant values (resistance, inductive reactance, capacitive reactance, leakage resistance, and dielectric loss tangent) of unknown facilities from the above equations,
A method for detecting abnormal conditions of power facilities and preventing expansion of accidents, including the step of determining and monitoring the presence or absence of an abnormality in the facility from an increase or decrease in the amount of change in the circuit constants obtained in the above step, and hardware therefor Device. The method of claim 1, in order to calculate the unknowns from the first-order circuit equation with two unknowns (circuit constants), two or more systems of linear equations are required. A monitoring method and a hardware device, characterized in that it enables two unknown circuit constants to be calculated by enabling The monitoring method and hardware device according to claim 1, further comprising a method of identifying what kind of abnormal phenomenon is expected in a facility when different changes are indicated among the calculated circuit constants according to the change type of the circuit constant. The measurement according to claim 1, wherein the operation conditions of the external power system apply a method of removing negative phase and image components, harmonics and high frequency components from the measured voltage and currents in order to exclude errors in calculating the corresponding facility circuit constant. Method and hardware device The resistance component of the parallel circuit among the circuit constants calculated according to claim 1 (

) And capacitive reactance (

), and by calculating the dielectric loss tangent (tan δ ), which can identify the insulation performance of the facility, it is possible to monitor and operate the insulation state of the facility at all times.

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