Method for discriminating property of single-phase fault of power transmission line with parallel electric reactor

Abstract

The invention discloses a method for discriminating the property of a single-phase fault of a power transmission line with a parallel electric reactor. The method comprises the steps: 1, carrying out uninterrupted sampling for a recovery voltage u of a head end at a fault phase when a single-phase grounding fault happens and the fault phase enters into a recovery voltage stage after arc blowout, and obtaining a sampling value sequence [u1(n)] of the recovery voltage u1(t); 2, comparing the amplitudes of all sampling points in the sampling value sequence [u1(n)] one by one, determining the minimum value Umin, the maximum value Umax, the time tmin corresponding to the minimum value Umin, and the time tmax corresponding to the maximum value Umax in all maximum value points, extracting all other maximum value points between the minimum value Umin and the maximum value Umax, calculating kset and the slope between two adjacent positive extreme points, and determining the minimum value kmin; determining that the single-phase fault is a transient fault if kmin is greater than kset; or else, determining that the single-phase fault is a permanent fault. The method employs a recovery voltage construction as judgment basis, can be easily achieved, effectively inhibits the spectrum leakage and picket fence effect of a DFT algorithm, shortens the time in determining the property of the fault, is high in response speed, and meets the demands of quick reclosure.

Description

technical field [0001] The invention relates to a power transmission line, in particular to a method for discriminating the nature of a single-phase fault of a power transmission line with a shunt reactor. Background technique [0002] According to the statistics of operation data, most of the faults on EHV and UHV long-distance transmission lines are single-phase ground faults, and most of them are transient faults. Therefore, it is of great significance to install reclosing devices on EHV and UHV transmission lines to improve the reliability of power supply and the stability of the system. [0003] The traditional reclosing is blind. When it recloses on a permanent fault, it will impact the system again and cause the working conditions of electrical equipment to deteriorate. The main function of adaptive reclosing is to distinguish the nature of the fault, and only reclose when there is a transient fault, avoiding the adverse consequences of blind reclosing. At present, ...

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Problems solved by technology

[0004] The arc characteristic is nonlinear, which is related to the system operation and the arc model, which makes the existing criterion method based on the arc characteristic complicated, fuzzy, and difficult to realize; The capacitive coupling voltage in the voltage is very low and the minimum value of the recovery voltage is very small, so there may be misjudgment based on the recovery voltage amplitude criterion

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