Single-end distance measurement method for single-phase ground fault of double-circuit lines paralleled on the same pole

Abstract

The invention discloses a single-end ranging method for a single-phase grounding fault of a double-circuit line paralleled on the same pole. The method of the present invention firstly measures the faulty phase electrical quantity at the protection installation place of the double-circuit line paralleled on the same pole and calculates the zero-sequence current of the second-circuit line of the double-circuit line paralleled on the same pole, and then adopts a one-dimensional search method to start from the same pole Starting from the line protection installation point of parallel double-circuit line I, the fixed step length is increased successively, and the single-end positioning error of each point on the same-pole parallel double-circuit line I is calculated sequentially until the same-pole parallel double-circuit line I The full length of the circuit, select the point with the smallest single-end positioning error as the fault point. The method of the present invention takes into account the influence of the zero-sequence mutual inductance between the lines, and eliminates the influence of the zero-sequence mutual inductance between the lines on the accuracy of the single-terminal distance measurement of the single-phase grounding fault of the parallel double-circuit line on the same pole; and the single-phase grounding fault point voltage is considered in the algorithm model The impact of the transition resistance on the single-phase ground fault single-end ranging accuracy of the parallel double-circuit line on the same pole is eliminated, and the ranging accuracy is very high.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-end distance measuring method for single-phase grounding faults of parallel double-circuit lines on the same pole against the influence of zero-sequence mutual inductance and transition resistance between lines. 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 rangi...

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 the same pole, and the zero-sequence mutual inductance will affect the zero-sequence compensation coefficient, which will lead to large errors in the ranging results of the impedance method

If a single-phase high-resistance grounding fault occurs on a parallel double-circuit line on the same pole, due to the comprehensive influence of the zero-sequence mutual inductance and high transition resistance between the lines, the ranging result of the impedance method often exceeds the full length of the line or there is no ranging result, which cannot provide accurate fault information Location information makes line fault inspection difficult, which is not conducive to rapid troubleshooting and rapid restoration of line power supply

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