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Line inter-phase stoppage impedance distance protection method based on addition impedance actual measurement revision

A technology of additional impedance and phase-to-phase faults, applied in emergency protection circuit devices, measuring resistance/reactance/impedance, measuring devices, etc. Effect

Active Publication Date: 2015-03-04
STATE GRID FUJIAN ELECTRIC POWER CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The additional impedance generated by the transition resistance will cause the refusal or malfunction of the impedance distance protection. The refusal of the protection will make the fault unable to be isolated from the grid in time, which is not conducive to the stable operation of the grid; Transfer, and then lead to the occurrence of large-scale power outage accidents

Method used

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  • Line inter-phase stoppage impedance distance protection method based on addition impedance actual measurement revision
  • Line inter-phase stoppage impedance distance protection method based on addition impedance actual measurement revision
  • Line inter-phase stoppage impedance distance protection method based on addition impedance actual measurement revision

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Embodiment Construction

[0016] The technical solution of the present invention will be further described in detail according to the accompanying drawings.

[0017] After a phase-to-phase short circuit fault occurs on the transmission line, the protection device measures the fault phase-to-phase voltage at the protection installation of the transmission line , fault phase-to-phase current , Normal phase negative sequence current ;in, =AB, BC, CA phase; φ=C, A, B phase.

[0018] The protective device calculates the additional impedance Δz by using the measured electrical quantity between the faulted phases:

[0019]

[0020] in, is the phase-to-phase voltage of the fault; is the phase-to-phase current of the fault; is the normal phase negative sequence current; ; =AB, BC, CA phase; φ=C, A, B phase; z 1 is the positive sequence impedance of the transmission line per unit length; is the fault phase-to-phase voltage the real part of is the fault phase-to-phase voltage the imag...

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Abstract

The invention discloses a line inter-phase stoppage impedance distance protection method based on an addition impedance actual measurement revision. According to the line inter-phase stoppage impedance distance protection method based on the addition impedance actual measurement revision, firstly, electrical quantity between fault phases is measured in a protective mode and is utilized to calculate additional impedance caused by a transitional resistor, then the actually-measured additional impedance is utilized to revise a stoppage impedance calculation result of traditional inter-phase impedance distance protection, and stoppage impedance zrelay which reflects a real stoppage distance is obtained, a protective device judges whether a motion equation, Iota zrelay-0.5(zset1+zset2)Iota <Iota 0.5(zset1-zset2)Iota, is true. If the equation is true, protection is conducted, and an action trip signal is sent, wherein the zset1 and the zset2 are respectively positive direction setting impedance and negative direction setting impedance. Due the fact that accurate measurement of the additional impedance caused by the transitional resistor is achieved according to the line inter-phase stoppage impedance distance protection method based on the addition impedance actual measurement revision, the actually-measured additional impedance is utilized to revise the stoppage impedance calculation result of the traditional inter-phase impedance distance protection, the stoppage impedance zrelay which reflects the real stoppage distance is obtained, influence on protective action performance caused by the transitional resistor is eliminated, and the line inter-phase stoppage impedance distance protection method based on the addition impedance actual measurement revision is suitable for electric transmission line phase fault impedance distance protection.

Description

technical field [0001] The invention relates to the technical field of impedance distance protection of electric power systems, in particular to a method for line interphase fault impedance distance protection based on additional impedance actual measurement and correction. Background technique [0002] The traditional phase-to-phase impedance distance protection uses the ratio of the phase-to-phase voltage of the fault phase to the phase-to-phase current of the fault phase to calculate the fault impedance ,because ,therefore . Therefore, it can be obtained that the calculation result of the fault impedance measured by the traditional phase-to-phase impedance distance protection consists of two parts: one part is the fault impedance xz that reflects the real fault distance 1 , the other part is the additional impedance caused by the transition resistance . in, is the phase-to-phase voltage of the fault; is the phase-to-phase short-circuit fault point voltage; ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/22G01R27/08
Inventor 曾惠敏林富洪
Owner STATE GRID FUJIAN ELECTRIC POWER CO LTD
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