CN116400158A - A method and system for eliminating interphase capacitance interference of lightning arrester leakage current - Google Patents

Abstract

The invention discloses a method and a system for eliminating interference of leakage current interphase capacitance of a lightning arrester, wherein the method comprises the following steps: acquiring a three-phase leakage current waveform of the lightning arrester and a corresponding three-phase line voltage waveform; based on the inter-phase capacitive coupling effect, establishing a relation between the three-phase leakage current waveform and the three-phase line voltage waveform; performing Fourier decomposition on the relation to obtain fundamental wave components of the three-phase leakage current waveform and the three-phase line voltage waveform, and obtaining a current coefficient matrix based on the fundamental wave components; decoupling the current coefficient matrix to obtain a decoupled current coefficient matrix; and acquiring a three-phase leakage current real waveform based on the decoupled current coefficient matrix and the three-phase line voltage waveform. The invention provides a method for removing measurement interference caused by interphase capacitance effect by utilizing the fundamental wave component of three-phase leakage current of a lightning arrester and the fundamental wave component of three-phase system voltage, which can realize accurate correction of the amplitude phase of the leakage current.

Description

A method and system for eliminating interphase capacitance interference of lightning arrester leakage current

technical field

The invention relates to the technical field of electric quantity measurement, and more specifically, to a method and system for eliminating interphase capacitance interference of leakage current of an arrester.

Background technique

Leakage current is the most important monitoring quantity to reflect the operating status of the arrester. The amplitude change of the leakage current of the arrester during operation can reflect whether the internal ZnO resistor is damp or not. Based on this, it can be judged whether the arrester can operate safely and stably. Sexual operation and maintenance measures. Therefore, accurate measurement of leakage current is particularly important.

Since the arrester itself has capacitance and nonlinear resistance, the leakage current can be divided into capacitive current and resistive current. The resistive current directly reflects the state of the internal ZnO resistor, and is an important indicator for leakage current monitoring. Arresters in substations are generally arranged in parallel. Due to the capacitive coupling effect between three-phase arresters, the leakage current of one-phase arrester consists of two parts: one part is the actual component generated by the line voltage applied to the nonlinear resistor, and the other part is the phase-to-phase current. The coupling component produced by the capacitance. Since the coupling component is generated by the voltage of the adjacent phase, the phase difference is 120° (leading or lagging), and the coupling capacitor is 90° ahead of the phase, the coupling component will cause the leakage current to be equal to the capacitive current and the resistive current. Changes will affect the actual measurement accuracy. Due to inter-phase coupling, the leakage current of phase A generally lags behind by 3-5°, the leakage current of phase B lags slightly, and the leakage current of phase C leads by 3-5°, and the amplitudes of phases A and C are relatively large, and the amplitude of phase B is relatively large. A small problem, as shown in Figure 1.

The existing lightning arrester online monitoring device in the substation has the function of real-time synchronous acquisition of leakage current and system voltage. The existing on-line monitoring devices for the leakage current of lightning arresters generally adopt the fixed angle compensation method, and the fixed angle compensation is given on the basis of the measurement results, so as to eliminate the error caused by phase-to-phase coupling. However, for arresters of different voltage levels, affected by factors such as different system voltage levels, different phase distances, and different phase sequences on site, the phase deviation is determined by the site conditions, and simple fixed angle compensation cannot accurately eliminate the error caused by phase-to-phase coupling. Sometimes even greater deviations are introduced. How to conveniently, quickly and accurately eliminate the error caused by the interphase capacitance to the leakage current measurement, obtain the true amplitude and phase of the leakage current, and provide the basic premise for the separation of the resistive current is an urgent problem to be solved.

Therefore, there is a need for a technology to eliminate the interphase capacitance interference of the leakage current of the arrester.

Contents of the invention

The technical scheme of the present invention provides a method and system for eliminating the interphase capacitance interference of the leakage current of the arrester, so as to solve the problem of how to eliminate the interphase capacitance interference of the leakage current of the arrester.

In order to solve the above problems, the present invention provides a method for eliminating the interphase capacitance interference of the leakage current of the arrester, the method comprising:

Obtain the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform;

Based on the interphase capacitive coupling effect, establishing a relational expression of the three-phase leakage current waveform and the three-phase line voltage waveform;

performing Fourier decomposition on the relational expression, obtaining the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and obtaining a current coefficient matrix based on the fundamental component;

Decoupling the current coefficient matrix to obtain a decoupled current coefficient matrix;

Based on the decoupled current coefficient matrix and the three-phase line voltage waveform, the real waveform of the three-phase leakage current is obtained.

Preferably, based on the waveform of the three-phase leakage current and the real waveform of the three-phase leakage current, the peak value of the three-phase leakage current, the effective value of the three-phase leakage current and the peak value of the three-phase leakage resistive current are obtained.

Preferably, the establishment of the relationship between the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect includes:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time.

Preferably, performing Fourier decomposition on the relational expression to obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and obtaining a current coefficient matrix based on the fundamental component includes:

Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix includes:

Perform Fourier decomposition on the relational expression, obtain the fundamental wave components of the three-phase leakage current waveform and the three-phase line voltage waveform, and generate a phasor form equation:

分别为A相、B相、C相泄漏电流波形相对于A相、B相、C相线路电压波形的相位；in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C;

Solving the phasor form equation to obtain the solution of each element in the current coefficient matrix MN;

Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

。

.

Preferably, the obtaining the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform includes:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real .

Preferably, it also includes:

The three-phase resistive current waveform is obtained based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real .

Based on another aspect of the present invention, the present invention provides a system for eliminating interphase capacitance interference of leakage current of arrester, said system comprising:

The first acquisition unit is used to acquire the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform;

A establishing unit, configured to establish a relational expression of the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect;

The second acquisition unit is configured to perform Fourier decomposition on the relational expression, acquire the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and acquire a current coefficient matrix based on the fundamental component;

a third acquisition unit, configured to decouple the current coefficient matrix, and obtain a decoupled current coefficient matrix;

The fourth obtaining unit is configured to obtain the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform.

Preferably, the fourth acquisition unit is further configured to acquire the peak value of the three-phase leakage current, the effective value of the three-phase leakage current and the resistance of the three-phase leakage current based on the waveform of the three-phase leakage current and the real waveform of the three-phase leakage current. current peak.

Preferably, the establishing unit is configured to establish the relationship between the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect, and is also configured to:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time.

Preferably, the second acquisition unit is configured to perform Fourier decomposition on the relational expression, acquire the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, based on the fundamental component Obtains the current coefficient matrix, also used to:

Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix includes:

Perform Fourier decomposition on the relational expression, obtain the fundamental wave components of the three-phase leakage current waveform and the three-phase line voltage waveform, and generate a phasor form equation:

分别为A相、B相、C相泄漏电流波形相对于A相、B相、C相线路电压波形的相位；in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C;

Solving the phasor form equation to obtain the solution of each element in the current coefficient matrix MN;

Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

。

.

Preferably, the fourth acquisition unit is configured to acquire the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform, and is also configured to:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real .

Preferably, the fourth acquisition unit is also used for:

The three-phase resistive current waveform is obtained based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real .

The technical solution of the present invention provides a method and system for eliminating interphase capacitance interference of lightning arrester leakage current, wherein the method includes: obtaining the three-phase leakage current waveform of the lightning arrester and the corresponding three-phase line voltage waveform; based on the interphase capacitance coupling effect, establishing the three-phase leakage current waveform and the relational expression of the three-phase line voltage waveform; perform Fourier decomposition on the relational expression to obtain the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and obtain the current coefficient matrix based on the fundamental component; the current coefficient matrix Perform decoupling to obtain the decoupled current coefficient matrix; based on the decoupled current coefficient matrix and the three-phase line voltage waveform, obtain the real waveform of the three-phase leakage current. The invention proposes a method for removing the measurement interference caused by the interphase capacitance effect by using the three-phase leakage current fundamental wave component of the lightning arrester and the three-phase system voltage fundamental wave component, which can realize accurate correction of the leakage current amplitude and phase.

Description of drawings

A more complete understanding of the exemplary embodiments of the present invention can be had by referring to the following drawings:

1 is a schematic diagram of a three-phase leakage current phasor of an arrester under the action of interphase capacitive coupling according to an existing preferred embodiment;

Fig. 2 is a kind of flow chart of the method for eliminating interphase capacitance interference of leakage current of lightning arrester according to preferred embodiment of the present invention; And

Fig. 3 is a structural diagram of a system for eliminating interphase capacitance interference of leakage current of an arrester according to a preferred embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present invention will now be described with reference to the drawings; however, the present invention may be embodied in many different forms and are not limited to the embodiments described herein, which are provided for the purpose of exhaustively and completely disclosing the present invention. invention and fully convey the scope of the invention to those skilled in the art. The terms used in the exemplary embodiments shown in the drawings do not limit the present invention. In the figures, the same units/elements are given the same reference numerals.

Unless otherwise specified, the terms (including scientific and technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it can be understood that terms defined by commonly used dictionaries should be understood to have consistent meanings in the context of their related fields, and should not be understood as idealized or overly formal meanings.

Fig. 2 is a flowchart of a method for eliminating interphase capacitance interference of leakage current of an arrester according to a preferred embodiment of the present invention. Aiming at the phase-to-phase coupling problem of the existing leakage current measurement, the invention proposes a decoupling method using the fundamental wave component to eliminate the coupling interference of the phase-to-phase capacitance to the measurement result of the leakage current. According to the amplitude and phase of the leakage current and the fundamental wave component of the line voltage, the present invention solves the characteristic matrix that the interphase capacitance affects the amplitude and phase of the leakage current, and then separates the real value of the leakage current from the coupling component caused by the interphase capacitance, Get the real value of the leakage current.

As shown in Fig. 2, the present invention provides a kind of method that eliminates the interphase capacitance interference of lightning arrester leakage current, and method comprises:

Step 101: Obtain the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform;

Step 102: Based on the interphase capacitive coupling effect, establish the relational expressions of the three-phase leakage current waveform and the three-phase line voltage waveform;

Preferably, based on the interphase capacitive coupling effect, the relational expressions of the three-phase leakage current waveform and the three-phase line voltage waveform are established, including:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time.

The present invention proposes a decoupling method for removing the interphase capacitance effect by using the three-phase leakage current fundamental component and the three-phase system voltage fundamental component, including the following steps:

(1) Use the current coil to measure the leakage current waveform of the three-phase arrester. The waveforms of phase A, phase B and phase C are respectively I _A , I _B and I _C . , B-phase, and C-phase waveforms are U _A , U _B , and U _C , respectively. Due to the capacitive coupling effect between phases, the relationship between the three-phase leakage current and the three-phase line voltage can be expressed as:

Among them, N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the capacitive current coefficient of the arrester itself, and M ₂ and M ₃ are the coupling capacitances generated by the interphase capacitance. Sexual current coefficient, into a matrix MN is the current coefficient matrix.

Step 103: Perform Fourier decomposition on the relational expression, obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and obtain the current coefficient matrix based on the fundamental component;

Step 104: Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix;

Preferably, Fourier decomposition is performed on the relational expression to obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and the current coefficient matrix is obtained based on the fundamental component, including:

Decouple the current coefficient matrix to obtain the decoupled current coefficient matrix, including:

Perform Fourier decomposition on the relational expression to obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and generate the phasor form equation:

分别为A相、B相、C相泄漏电流波形相对于A相、B相、C相线路电压波形的相位；in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C;

Solve the phasor form equation to obtain the solution of each element in the current coefficient matrix MN;

Decouple the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

The present invention obtains the fundamental component of the leakage current and the line voltage through Fourier decomposition, and writes it into a phasor form to obtain the following equation:

分别为A相、B相、C相泄漏电流相对于A相、B相、C相系统电压的相位。in

They are the phases of phase A, phase B, and phase C leakage current relative to the system voltage of phase A, phase B, and phase C, respectively.

The present invention solves the equation to obtain the solution of each element in the current coefficient matrix MN.

The present invention utilizes the current coefficient matrix MN to make the coupling capacitive current coefficient zero to obtain the decoupled current coefficient matrix MN'.

Step 105: Obtain the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform.

Preferably, based on the waveform of the three-phase leakage current and the real waveform of the three-phase leakage current, the peak value of the three-phase leakage current, the effective value of the three-phase leakage current and the peak value of the three-phase leakage resistive current are obtained.

Preferably, based on the decoupled current coefficient matrix and the three-phase line voltage waveform, the real waveform of the three-phase leakage current is obtained, including:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real .

Preferably, it also includes:

Obtain the three-phase resistive current waveform based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real .

According to the system voltage waveform, the present invention calculates and obtains the three-phase leakage of A phase, B phase and C phase

Current real waveform:

According to the leakage current waveforms of phase A, phase B and phase C, and the real waveforms of phase A, phase B and phase C leakage current calculated by formula (4), the resistive current waveforms of phase A, phase B and phase C can be obtained :

Using the three-phase leakage current fundamental wave and the system voltage fundamental wave waveform, the parameters such as the amplitude and phase of the leakage current and system voltage are extracted, and the current coefficient matrix is calculated to realize the method of eliminating the coupling interference of the interphase capacitance on the leakage current of each phase arrester.

The invention takes the lightning arrester at the line outlet of a substation as an example, obtains the three-phase leakage current waveform and the corresponding three-phase line voltage waveform through the lightning arrester online monitoring system; performs Fourier transformation on the waveform to obtain the fundamental wave amplitude and phase.

In the present invention, the leakage current, the amplitude and phase of the fundamental wave of the line voltage are substituted into formula (2), and the corresponding current coefficient matrix MN is obtained through calculation.

In the present invention, only the elements on the main diagonal line are retained in the current coefficient matrix MN to obtain the decoupled current coefficient matrix MN'.

The invention multiplies the decoupled current coefficient matrix MN' by the line voltage waveform to obtain the real waveform of the three-phase leakage current, and then can calculate the peak value, effective value and resistive current peak value of the three-phase leakage current.

The present invention proposes a method for removing the measurement interference caused by the interphase capacitance effect by using the fundamental component of the three-phase leakage current of the surge arrester and the fundamental component of the voltage of the three-phase system, which can realize accurate correction of the amplitude and phase of the leakage current, and has the following advantages:

(1) The method proposed by the present invention is not affected by factors such as the distance between arresters, phase sequence sequence, system voltage level, etc., and does not need to adjust the algorithm according to the site layout of the arrester.

(2) The required data are easy to obtain and the method is easy to operate. The method proposed by the invention only needs to synchronously measure the three-phase leakage current and the system voltage waveform, extract the amplitude and phase of the fundamental wave, and then calculate and separate the real waveform of the three-phase leakage current. All data have been obtained by mature means, no need to add additional equipment.

Fig. 3 is a structural diagram of a system for eliminating interphase capacitance interference of leakage current of an arrester according to a preferred embodiment of the present invention.

As shown in Figure 3, the present invention provides a kind of system that eliminates the interphase capacitance interference of leakage current of lightning arrester, and system comprises:

The first acquisition unit 301 is configured to acquire the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform;

Establishing unit 302, configured to establish the relationship between the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect;

Preferably, the establishment unit 302 is configured to establish the relational expressions of the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect, and is also used for:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time.

The second acquisition unit 303 is configured to perform Fourier decomposition on the relational expression, acquire the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and acquire the current coefficient matrix based on the fundamental component;

Preferably, the second obtaining unit 303 is configured to perform Fourier decomposition on the relational expression, obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, obtain the current coefficient matrix based on the fundamental component, and is also used for:

Decouple the current coefficient matrix to obtain the decoupled current coefficient matrix, including:

Perform Fourier decomposition on the relational expression to obtain the fundamental component of the three-phase leakage current waveform and the three-phase line voltage waveform, and generate the phasor form equation:

分别为A相、B相、C相泄漏电流波形相对于A相、B相、C相线路电压波形的相位；in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C;

Solve the phasor form equation to obtain the solution of each element in the current coefficient matrix MN;

Decouple the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

。

.

The third acquiring unit 304 is configured to decouple the current coefficient matrix, and acquire the decoupled current coefficient matrix;

The fourth obtaining unit 305 is configured to obtain the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform.

Preferably, the fourth acquiring unit 305 is further configured to acquire the peak value of the three-phase leakage current, the effective value of the three-phase leakage current and the peak value of the three-phase leakage resistive current based on the waveform of the three-phase leakage current and the real waveform of the three-phase leakage current.

Preferably, the fourth obtaining unit 305 is used to obtain the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform, and is also used for:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real .

Preferably, the fourth acquiring unit 305 is also configured to:

Obtain the three-phase resistive current waveform based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real .

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein. The solutions in the embodiments of the present invention can be realized by using various computer languages, for example, the object-oriented programming language Java and the literal translation scripting language JavaScript.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

The invention has been described with reference to a small number of embodiments. However, it is clear to a person skilled in the art that other embodiments than the invention disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise therein. All references to "a/the/the [means, component, etc.]" are openly construed to mean at least one instance of said means, component, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Claims (12)

1. A method for eliminating interphase capacitance interference of surge arrester leakage current, said method comprising: Obtain the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform; Based on the interphase capacitive coupling effect, establishing a relational expression of the three-phase leakage current waveform and the three-phase line voltage waveform; performing Fourier decomposition on the relational expression, obtaining the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and obtaining a current coefficient matrix based on the fundamental component; Decoupling the current coefficient matrix to obtain a decoupled current coefficient matrix; Based on the decoupled current coefficient matrix and the three-phase line voltage waveform, the real waveform of the three-phase leakage current is obtained. 2. The method according to claim 1, based on the three-phase leakage current waveform and the real waveform of the three-phase leakage current, obtain the peak value of the three-phase leakage current, the effective value of the three-phase leakage current and the peak value of the three-phase leakage resistive current . 3. The method according to claim 1, said based on interphase capacitive coupling effect, establishing the relational expression of said three-phase leakage current waveform and said three-phase line voltage waveform, comprising:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time. 4. The method according to claim 3, said carrying out Fourier decomposition to said relational expression, obtaining said three-phase leakage current waveform and the fundamental component of said three-phase line voltage waveform, based on said fundamental The components get the current coefficient matrix, including: Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix includes: Perform Fourier decomposition on the relational expression, obtain the fundamental wave components of the three-phase leakage current waveform and the three-phase line voltage waveform, and generate a phasor form equation:

in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C; Solving the phasor form equation to obtain the solution of each element in the current coefficient matrix MN; Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

. 5. The method according to claim 4, said obtaining the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform, comprising:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real . 6. The method of claim 5, further comprising: The three-phase resistive current waveform is obtained based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real . 7. A system for eliminating interphase capacitance interference of lightning arrester leakage current, said system comprising: The first acquisition unit is used to acquire the three-phase leakage current waveform of the arrester and the corresponding three-phase line voltage waveform; A establishing unit, configured to establish a relational expression of the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect; The second acquisition unit is configured to perform Fourier decomposition on the relational expression, acquire the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and acquire a current coefficient matrix based on the fundamental component; a third acquisition unit, configured to decouple the current coefficient matrix, and obtain a decoupled current coefficient matrix; The fourth obtaining unit is configured to obtain the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform. 8. The system according to claim 7, the fourth acquisition unit is further configured to acquire the peak value of the three-phase leakage current, the three-phase leakage current peak value, and the three-phase leakage current based on the waveform of the three-phase leakage current and the real waveform of the three-phase leakage current. RMS and peak value of three-phase leakage resistive current. 9. The system according to claim 7, the establishing unit is configured to establish the relational expression of the three-phase leakage current waveform and the three-phase line voltage waveform based on the interphase capacitive coupling effect, and is further configured to:

Among them, the current waveforms of phase A, phase B, and phase C in the three-phase leakage current waveform are respectively I _A , I _B , and I _C , and the voltage waveforms of phase A, phase B, and phase C in the three-phase line voltage waveform are U _A , U _B , U _C , N ₁ , N ₂ , and N ₃ are the resistive current coefficients of phase A, phase B, and phase C respectively, M ₁ is the body capacitive current coefficient generated by the arrester body, and M ₂ and M ₃ are interphase capacitances The resulting coupling capacitive current coefficient, t is time. 10. The system according to claim 9, the second acquisition unit is configured to perform Fourier decomposition on the relational expression to acquire the fundamental wave of the three-phase leakage current waveform and the three-phase line voltage waveform Component, based on the fundamental component to obtain the current coefficient matrix, is also used for: Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix includes: Perform Fourier decomposition on the relational expression, obtain the three-phase leakage current waveform and the fundamental component of the three-phase line voltage waveform, and generate a phasor form equation:

in

Respectively, the phases of the leakage current waveforms of phase A, phase B and phase C relative to the line voltage waveforms of phase A, phase B and phase C; Solving the phasor form equation to obtain the solution of each element in the current coefficient matrix MN; Decoupling the current coefficient matrix to obtain the decoupled current coefficient matrix MN':

. 11. The system according to claim 10, the fourth acquisition unit is configured to acquire the real waveform of the three-phase leakage current based on the decoupled current coefficient matrix and the three-phase line voltage waveform, and is further configured to:

Among them, the real current waveforms of phase A, phase B and phase C in the three-phase leakage real current waveforms are respectively I _A-real , I _B-real and I _C-real . 12. The system according to claim 11, the fourth acquisition unit is further configured to: acquire a three-phase resistive current waveform based on the real waveform of the three-phase leakage current:

Among them, the resistive current waveforms of phase A, phase B and phase C are respectively I _A—R-real , I _BR-real , and I _CR-real .

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