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Quick identification method for permanent fault before single-phase reclosing of power transmission line

A single-phase reclosing, permanent fault technology, applied in circuit devices, fault locations, emergency protection circuit devices, etc., can solve problems such as poor practicability, low reliability, and long discrimination time.

Active Publication Date: 2010-10-13
STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST +1
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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for quick identification of permanent faults before single-phase reclosing of transmission lines, which can utilize the low-frequency free component amplitude characteristics of disconnected phase shunt reactor current based on the stable and reliable electrical quantity in the recovery voltage stage, Identify single-phase permanent faults of transmission lines more reliably, and solve the problems of low reliability, long identification time and poor practicability of existing methods

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  • Quick identification method for permanent fault before single-phase reclosing of power transmission line
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  • Quick identification method for permanent fault before single-phase reclosing of power transmission line

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Embodiment Construction

[0036] refer to figure 1The reactors at both ends of the transmission line MN are respectively equipped with reactor protection, and the current transformers TA1 and TA2 respectively detect the real-time current of the three-phase shunt reactors at the M terminal and N terminal. Inside the dotted line frame is the hardware structure, which is composed of three parts: data acquisition system, microcomputer main system and input-output system. The method of the present invention is realized by the microcomputer DSP main system through programming. Taking the N side as an example, the input value is the current of the three-phase shunt reactor, which is obtained by the current transformer TA2 on the side of the shunt reactor. After / D conversion, it is sent to the microcomputer DSP main system. Through this method, the fault phase is firstly selected, and the single-phase fault is confirmed and tripped. After that, the initial amplitude of the low-frequency natural vibration comp...

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Abstract

The invention relates to the field of power transmission line relay protection of a power system, and discloses a quick identification method for a permanent fault before single-phase reclosing of a power transmission line. At least one end of the power transmission line is provided with a three-phase parallel reactor and a neutral-point small reactor. The method comprises the following steps of: firstly, acquiring real-time current iLphi(t) of the three-phase parallel reactor, and performing single-phase fault identification and tripping state determination; secondly, disconnecting a least square fitting model of the current iLphi(t) of the parallel reactor after temporary fault arc blowout of a preset line, and solving a low-frequency free oscillating component initial amplitude IL and a power frequency component amplitude I1 of the current of the disconnected parallel reactor; and finally, performing single-phase fault property judgment according to the permanent fault criteria that IL is less than KkI1 and Kk is equal to 0.1 to 0.3.

Description

technical field [0001] The invention relates to the field of relay protection of transmission lines in electric power systems, in particular to a method for quickly identifying permanent faults before single-phase reclosing of transmission lines. Background technique [0002] Single-phase reclosing technology is an effective measure to quickly restore power supply and maintain system stability in modern EHV / UHV power grids. However, the action of the existing single-phase reclosing is blind. After the single-phase fault trips, it will automatically reclose after a fixed time limit of 0.5s to 1.5s, and there is a secondary short-circuit impact risk caused by reclosing and permanent faults; at the same time, in the In the case of unsuccessful reclosing of EHV / UHV lines, the asynchronous secondary tripping in a short period of time will generate dangerous overvoltage, which seriously threatens the safety of electrical main equipment and the stability of system operation. In or...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/06H02H7/26G01R31/08
Inventor 石光索南加乐郭耀珠邵文权刘巍宋国兵
Owner STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST
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