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Zero-sequence voltage protection method for single-phase ground fault of transmission line

A single-phase ground fault, transmission line technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problem of affecting the action performance of impedance relay, the sensitivity of impedance distance protection action is reduced, and the influence of impedance distance protection action performance cannot be ignored.

Active Publication Date: 2016-03-02
STATE GRID CORP OF CHINA +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Considering the influence of the distributed capacitive current along the transmission line, the relationship between the fault impedance and the fault distance is a hyperbolic tangent function. The amplitude and phase characteristics of the hyperbolic tangent function determine that the impedance relay has poor resistance to transition resistance, and the additional impedance brought by the transition resistance will seriously affect Action performance of impedance relay
EHV / UHV transmission lines transmit large-capacity electric energy and are heavy-duty transmission lines. Heavy-load currents will reduce the action sensitivity of impedance distance protection, and the impact of heavy-load current on the action performance of impedance distance protection cannot be ignored.

Method used

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  • Zero-sequence voltage protection method for single-phase ground fault of transmission line
  • Zero-sequence voltage protection method for single-phase ground fault of transmission line
  • Zero-sequence voltage protection method for single-phase ground fault of transmission line

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Embodiment Construction

[0017] The technical solutions of the present invention will be further described in detail below in conjunction with the embodiments.

[0018] figure 1 It is a schematic diagram of the line transmission system applying the present invention. figure 1 CVT is a voltage transformer, and CT is a current transformer. The protection device samples the voltage of the voltage transformer CVT 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 then the protection device uses the Fourier algorithm for the collected instantaneous value of the voltage and current Calculation of fault phase negative-sequence voltage at the installation of transmission line protection , fault phase negative sequence current , zero sequence voltage and zero sequence current ; Among them, Φ=A phase, B phase, C phase.

[0019] The protection device calculates the equival...

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Abstract

The invention discloses a zero-sequence voltage protection method for single-phase grounding faults of a power transmission line. The method includes firstly, respectively computing equivalent zero-sequence voltage of a power transmission line protection setting range and voltage of the power transmission line protection setting range by the aid of zero-sequence voltage, zero-sequence current, fault-phase negative-sequence voltage and fault-phase negative-sequence current of power transmission line protection mounting positions, secondly, judging whether amplitude of the zero-sequence voltage of the power transmission line protection setting range is higher than that of the equivalent zero-sequence voltage of the power transmission line protection mounting positions or not, and if yes, sending an action tripping signal to trip off breakers at two ends of the power transmission line. A distributed parameter model is used as a physical model, action performance is unaffected by distributed capacitance current, and the method is applicable to any voltage classes, in particular to super-high-voltage / ultra-high-voltage power transmission lines.

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 zero-sequence voltage protection method of a power transmission line. Background technique [0002] The power frequency variation distance protection constitutes the distance protection by reflecting the sudden change of the working voltage amplitude. This method has the advantages of being less affected by the operation mode of the power system and having a strong ability to resist transition resistance. However, since the sudden change in the working voltage amplitude used in this method only exists in the initial fault stage, it cannot be used as a backup protection for EHV / UHV AC transmission lines. [0003] Impedance distance protection reflects the fault distance according to the measured impedance to distinguish whether the fault point is inside the protection zone or outside the protection zone. Impedance distanc...

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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