Single-phase-to-earth fault relay protection method based on fault impedance phase characteristics

A single-phase ground fault and phase characteristic technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve problems such as power outage accidents, unfavorable safe and stable operation of the power grid, and large power flow shifts in the power grid, and achieve correct and reliable actions.

Active Publication Date: 2015-10-28
STATE GRID CORP OF CHINA +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The additional fault impedance caused by the transition resistance is likely to cause the traditional grounding distance protection to refuse or malfunction
The refusal of the traditional grounding distance protection will make the fault unable to be isolated from the power grid in time, which is not good for the safe and stable operation of the power grid; the wrong operation of the traditional grounding distance protection will lead to the expansion of the fault range, and even lead to a large shift of the power grid power flow, which will lead to large-scale power outages in the power grid

Method used

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  • Single-phase-to-earth fault relay protection method based on fault impedance phase characteristics
  • Single-phase-to-earth fault relay protection method based on fault impedance phase characteristics
  • Single-phase-to-earth fault relay protection method based on fault impedance phase characteristics

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Embodiment Construction

[0015] The technical solution of the present invention will be further described in detail according to the accompanying drawings.

[0016] figure 1 It is a schematic diagram of the line transmission system applying the present invention. figure 1 Among them, PT is a voltage transformer, and CT is a current transformer. The protection device samples the voltage waveform of the voltage transformer PT and the current waveform of the current transformer CT at the installation place of the transmission line protection to obtain the instantaneous value of the voltage and current, and calculates the instantaneous value of the voltage and current obtained by sampling using the Fourier algorithm Fault phase voltage at transmission line protection installation , fault phase negative sequence voltage , fault phase current and zero sequence current , as the input quantity; among them, φ=A phase, B phase, C phase.

[0017] The protection device uses the transmission line to prot...

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Abstract

The invention discloses a single-phase line earth fault relay protection method based on a fault impedance phase characteristic. The method comprises the steps that line fault impedance from a single-phase earth fault point to a protection setting range of the power transmission line is calculated by utilizing fault phase voltage, fault phase negative-sequence voltage, fault phase current and zero-sequence current at protection mounting of a power transmission line; whether a phase angle of the line fault impedance from the single-phase earth fault point to the protection setting range of the power transmission line is between 135 degrees and 225 degrees is judged; and if so, a protection device emits an action trip signal. The method overcomes influences of transition resistance and load current on the protection action performance, can correctly and reliably act during a single-phase high-resistance earth fault of the power transmission line, and is suitable for the single-phase earth fault relay protection of the power transmission line in the whole fault process.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-phase ground fault relay protection method based on fault impedance phase characteristics. Background technique [0002] The calculation formula of measuring line fault impedance z for traditional grounding distance protection is ,because ,therefore , that is, the line fault impedance z measured by the traditional grounding distance protection is composed of two parts, one part is the line fault impedance xz reflecting the real fault distance 1 , the other part is the additional fault impedance caused by the transition resistance . In the above formula, is the fault phase voltage; is the fault point voltage; is the fault phase current; is the zero-sequence current; φ is the fault phase: A phase, B phase, C phase; z 1 is the positive sequence impedance of the transmission line per unit length; z 0 is the zero-sequence imp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
Inventor 林富洪曾惠敏
Owner STATE GRID CORP OF CHINA
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