Using Zero-sequence Voltage Distribution Characteristics to Realize the Single-end Distance Measurement Method of Single-phase-to-ground Fault

Abstract

The invention discloses a line single-phase earth fault single-terminal location method implemented by the aid of zero-sequence voltage distribution characteristics. The line single-phase earth fault single-terminal location method includes sequentially computing an absolute value of the difference between an amplitude value of an equivalent zero-sequence voltage of each point on a power transmission line and an amplitude value of a zero-sequence voltage of the point by the aid of a one-dimensional search process and a zero-sequence voltage, a zero-sequence current, fault-phase negative-sequence voltages and fault-phase negative-sequence currents at a power transmission line protection mounting position until computation is performed on all points in the total length of the power transmission line; selecting the distance from the power transmission line protection mounting position to the point corresponding to the minimum absolute value of the difference between the amplitude value of the equivalent zero-sequence voltage of the point and the amplitude value of the zero-sequence voltage of the point as the fault distance. The line single-phase earth fault single-terminal location method has the advantages that power transmission line single-phase earth fault single-terminal location is implemented by the aid of the distribution characteristics of the zero-sequence voltages along the power transmission line, influence of transition resistance, fault positions and load currents on the location precision is eliminated in principle, and the location precision is high.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-end ranging method for single-phase grounding faults of lines by using the distribution characteristics of zero-sequence voltage. Background technique [0002] Single-ended fault location methods for transmission lines are mainly divided into traveling wave method and impedance method. The traveling wave method utilizes the transmission properties of fault transient traveling waves to measure distance. It has high precision and is not affected by system operation mode and excessive resistance. application. The impedance method calculates the impedance of the fault loop by using the voltage and current after the fault, and performs distance measurement according to the characteristic that the length of the line is proportional to the impedance. It is simple and reliable, but it is affected by factors such as the transition resistance of the...

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Problems solved by technology

In the case of medium and low-resistance short-circuit faults, due to the obvious drop in voltage along the line, the error in estimating the voltage phase angle of the fault point by using the negative-sequence current phase angle at the observation point has little effect on the ranging results; but in the case of high-resistance short-circuit faults, Because the voltage difference of each point along the line is very small, the error in estimating the voltage phase angle of the fault point by using the negative sequence current phase angle at the observation point plus the influence of the transient process, the distance measurement error of this method is relatively large

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