Double-circuit line non-in-phase jumper wire earth fault single-end distance measurement method

Abstract

The invention discloses a double-circuit line non-in-phase jumper wire earth fault single-end distance measurement method. The method comprises the steps that the fault phase voltage, the fault phase current and the zero sequence current at the protection installing position of a circuit line I of a same-tower double-circuit line are measured, the zero sequence compensating current is calculated by considering influences of zero sequence mutual inductance between the lines, the imaginary part of virtual resistance at the point of a double-circuit line non-in-phase jumper wire earth fault is calculated, the imaginary parts of virtual resistance of points on the circuit line I of the same-tower double-circuit line are sequentially calculated through a one-dimensional search method, and accurate distance measurement of the double-circuit line non-in-phase jumper wire earth fault is achieved according to the amplitude characteristic that the absolute value of the difference between the imaginary parts of virtual resistance at the point of the double-circuit line non-in-phase jumper wire earth fault is minimum. Influences caused by zero sequence mutual inductance between lines, transition resistance and load current on the accuracy of fault distance measurement are eliminated, a forward outlet is protected so that no fault distance measurement dead zones exist when the double-circuit line non-in-phase jumper wire earth fault happens, and the double-circuit line non-in-phase jumper wire earth fault single-end distance measurement method has very high single-end fault distance measurement accuracy.

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 non-identical phase cross-line grounding faults of double-circuit lines based on the amplitude characteristics of the imaginary part of virtual impedance. Background technique [0002] Divided from the electrical quantity used for distance measurement, fault location methods can be divided into two categories: double-ended ranging and single-ended ranging. The double-terminal fault location method is a method to determine the fault location of the transmission line by using the electrical quantity at both ends of the transmission line. It needs to obtain the electrical quantity of the opposite end through the channel, so it is highly dependent on the channel, and it is also vulnerable to the double-terminal sampling value in actual use. Synchronization effects. The single-ended ranging method is a method that only us...

AI Technical Summary

Problems solved by technology

The traveling wave method utilizes the transmission properties of fault transient traveling waves for distance measurement. It has high precision and is not affected by the operation mode and excessive resistance. application

The impedance method uses the voltage and current after the fault to calculate the impedance of the fault loop, and performs distance measurement according to the characteristic that the length of the line is proportional to the impedance. When measuring terminal faults, the distance measurement accuracy is seriously affected by the transition resistance of the fault point and the zero-sequence mutual inductance between lines.

There is zero-sequence mutual inductance between double-circuit lines on th

Images