Calculation method of MOA resistive fundamental current increase rate based on resultant vectors

A technique for synthesizing vector and fundamental wave currents, applied in the directions of measuring current/voltage, measuring electricity, measuring electric variables, etc., can solve problems such as influence, avoid misjudgment, improve absolute accuracy and relative accuracy, and overcome interphase coupling capacitance Effect

Active Publication Date: 2018-10-12
STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO
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Problems solved by technology

The above-mentioned resistive current calculation method has the following problems: since the arrester works in a high-voltage environment, there will inevitably be phase-to-phase coupling cap

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  • Calculation method of MOA resistive fundamental current increase rate based on resultant vectors
  • Calculation method of MOA resistive fundamental current increase rate based on resultant vectors
  • Calculation method of MOA resistive fundamental current increase rate based on resultant vectors

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[0016] The principles and solutions of the present invention will be further described below in conjunction with the drawings and specific embodiments.

[0017] The three-phase arresters in the power system are usually installed in a "one" arrangement. The present invention discusses the three-phase MOA model arranged in a word. Since A and C are far apart, the interphase capacitive coupling current between them can be ignored, and only the interphase capacitive coupling current between A, B and B, C is considered, and the equivalent circuit of the three-phase MOA working state is obtained as figure 1 Shown. In the picture: Is the three-phase voltage vector of the power grid; It is the actual valve current vector, but it cannot be directly measured; The leakage current vector, which is the doped coupling capacitor current, can be directly measured, but is affected by the coupling capacitor; Is the coupling capacitor current vector between phases; R a , R b , R c Three-phase MO...

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Abstract

The invention discloses a calculation method of MOA resistive fundamental current increase rate based on resultant vectors. Firstly the initial inclined angle theta of the fundamental current and thevoltage vector is solved according to the leakage current resultant vectors I<arrowhead><a+b>, I<arrowhead><a-c> and I<arrowhead><c+b> of three-phase doped coupled capacitive current; then the inclined angles alpha, beta and gamma between the resultant vectors I<arrowhead><a-c> and I<arrowhead><a+b>, I<arrowhead><a+b> and I<arrowhead><c+b> and I<arrowhead><a-c> and I<arrowhead><c+b> are determined, and the phase of arrester resistive current increase is judged according to the change trend of the inclined angles alpha, beta and gamma; and finally the increment of the corresponding phase resistive current fundamental wave is solved according to the phase of arrester resistive current increase and the initial inclined angle theta of the current vector and the voltage vector. According to themethod, the influence of the interphase coupling capacitance on resistive current measurement can be eliminated without the influence of the voltage phase.

Description

technical field [0001] The invention belongs to the field of power system safety control, and in particular relates to a method for calculating the growth rate of MOA resistive fundamental wave current based on a synthetic vector. Background technique [0002] Metal Oxide Surge Arrester (MOA) has the characteristics of good protection, large flow capacity and simple structure, and is widely used in power systems. The resistive leakage current of arrester is an important characteristic parameter to judge the operation state of MOA. [0003] At present, the main methods for measuring the resistive leakage current of arresters are: resistive current fundamental wave method, resistive current third harmonic method and capacitive current compensation method. Resistive current fundamental wave method, firstly measure the full current of MOA of each phase, and measure the voltage on the secondary side of PT at the same time, then perform FFT calculation on the voltage and current ...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R31/00
CPCG01R19/00G01R31/00
Inventor 张自伟衡思坤郑许林高赫朱立位于跃
Owner STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO
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