Longitudinal impedance-based T-shaped line protection and calculation method

A technology of longitudinal impedance and calculation method, which is applied in the direction of detecting faults, instruments, and measuring devices according to conductor types, and can solve the problems of transient saturation effects of current transformers and difficulties in setting current differential protection, so as to overcome misoperation and eliminate Phase-to-phase coupling, high reliability effects

Inactive Publication Date: 2016-11-02
XI'AN POLYTECHNIC UNIVERSITY
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Problems solved by technology

[0004] The purpose of the present invention is to provide a T-type line protection calculation method based on longitudinal impedance, which can accurately and quickly identify and act effectively after a high-voltage transmission line fault, and overcomes the difficulty in setting the traditional current differential protection and is susceptible to transient saturation of the current transformer. problem of influence

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  • Longitudinal impedance-based T-shaped line protection and calculation method
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  • Longitudinal impedance-based T-shaped line protection and calculation method

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[0015] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0016] The present invention is based on the T-shaped line protection calculation method of longitudinal impedance, specifically implements according to the following steps:

[0017] Step 1: Calculation of the longitudinal impedance when faults occur inside and outside the single-phase line of the T-type line.

[0018] Such as figure 1 As shown, m, n and p are the three-terminal electrical measurement terminals of the protected transmission line; Z m ,Z n ,Z p are the system impedance of the three terminals of the line; z is the positive sequence impedance of the line per unit length; d is the measurement distance from the m terminal to the fault point when there is an internal fault, D 1 is the distance from m terminal to T interface, D 2 is the distance from n-terminal to T-interface, D 3 is the distance from the p terminal to the T i...

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Abstract

The invention discloses a longitudinal impedance-based T-shaped line protection and calculation method which comprises the following steps: longitudinal impedance is calculated when internal faults and external faults occur in a T-shaped single phase line; the longitudinal impedance is analyzed under a three phase line model, and the longitudinal impedance is analyzed in a condition of current transformer transient saturation. Via use of the longitudinal impedance-based T-shaped line protection and calculation method disclosed in the invention, faults can be accurately and rapidly determined and effectively responded to after high tension transmission line faults occur, and a problem of difficult setting of a traditional current differential protection mode and specifically a problem that traditional current differential protection mode is susceptible to current transformer transient saturation can be overcome.

Description

technical field [0001] The invention belongs to the field of relay protection of AC transmission lines, in particular to a calculation method for T-type line protection based on longitudinal impedance. Background technique [0002] With the development of the power system, more and more T-shaped transmission lines appear in high-voltage and ultra-high-voltage power grids. After a fault occurs, it is required that the protection can be quickly identified and acted effectively. However, due to the high transmission power and heavy load, once the T-shaped line fails, it will cause a large-scale power outage. Therefore, the protection of T-shaped high-voltage transmission lines has attracted more and more attention in recent years. [0003] Although the current differential protection based on fault components can effectively avoid the influence of load flow, many schemes have been proposed on this basis. The differential protection scheme that takes the maximum value of the t...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 夏经德王波黄新波
Owner XI'AN POLYTECHNIC UNIVERSITY
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