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Flexible grounding system grounding fault protection method based on fault phase voltage polarization

A technology of fault phase voltage and grounding system, which is applied in the direction of fault location, measurement of electrical variables, measurement of current/voltage, etc., can solve the problems that the protection method cannot be directly applied, is not comprehensive, and malfunctions, so as to avoid further expansion of accidents and withstand The effect of improving the ability of the transition resistance and avoiding the lack of accuracy

Pending Publication Date: 2022-08-02
ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY +2
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Problems solved by technology

However, the understanding of its ground fault process and fault characteristics is still not comprehensive at present. The protection methods of the existing small resistance grounding system or small current grounding system cannot be directly applied, and there are risks of false operation and refusal to operate. It is urgent to study special protection methods. And improve the sensitivity of the protection when the high resistance is grounded

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  • Flexible grounding system grounding fault protection method based on fault phase voltage polarization
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  • Flexible grounding system grounding fault protection method based on fault phase voltage polarization

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Embodiment Construction

[0018] Attached below figure 1 to the attached Figure 4 The present invention will be further described.

[0019] as attached figure 1 As shown in the figure, a ground fault protection method for flexible grounding system based on fault phase voltage polarization includes:

[0020] a) After the fault occurs, complete the selection of the faulty phase;

[0021] b) After the neutral point is connected in parallel with the small resistor, if the zero-sequence current at the detection point is greater than or equal to the zero-sequence current demarcation value I bdy Or if the phase difference between the fault phase voltage and the zero-sequence current at the detection point is within the range of -34.8° to 55.2°, it is determined to be an internal fault;

[0022] c) After the neutral point is connected in parallel with the small resistor, if the phase difference between the fault phase voltage and the zero-sequence current at the detection point is within the range of 55.2...

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Abstract

A flexible grounding system grounding fault protection method based on fault phase voltage polarization uses fault information of the whole process before and after parallel resistor input, realizes selection of a fault phase in an arc suppression coil compensation stage, and adopts definite time limit zero sequence current protection and zero sequence current out-of-limit action when transition resistance is small. When the transition resistance is high and the zero-sequence voltage is small, the fault phase voltage is used as the polarization of the zero-sequence voltage and the phase ratio of the zero-sequence voltage to the zero-sequence current, the problem that the precision of the zero-sequence voltage transformer is insufficient during high-resistance grounding is effectively avoided, and compared with a traditional zero-sequence over-current protection method, the transition resistance tolerance capacity of the zero-sequence over-current protection method is remarkably improved. According to the method, different measures are taken for an instantaneous grounding fault and a permanent grounding fault in single-phase grounding, so that rapid and accurate isolation of the permanent grounding fault is ensured, further expansion of an accident caused by long-term existence of power frequency overvoltage of a system is avoided, and the instantaneous grounding fault can be compensated to disappear automatically without tripping.

Description

technical field [0001] The invention relates to the field of distribution network fault detection and protection, in particular to a ground fault protection method for a flexible grounding system based on a fault phase voltage polarization. Background technique [0002] Ground fault processing technology of arc suppression coil connected in parallel with small resistance grounded distribution network: for transient faults, arc suppression coil is used for arc suppression; for low resistance intermittent faults and permanent faults, parallel resistance is used to increase fault residual current and achieve rapid Line selection, positioning and segment isolation. According to the size of the parallel resistance, the parallel small resistance grounding system of the arc suppression coil is divided into two ways: parallel medium resistance and parallel small resistance. The parallel resistance is an auxiliary means to solve the fault protection problem of the resonant grounding...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08G01R31/52G01R19/175H02H7/26
CPCG01R31/086G01R31/52G01R19/175H02H7/26Y04S10/52
Inventor 张婉婕李玉敦南东亮孙孔明刘晓徐宪泽薛永端梁正堂黄强李娜王宏刘萌李宽
Owner ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY
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