Rapid positioning method for double-circuit line non-same-name phase crossover line ground fault

Abstract

The invention discloses a rapid positioning method for a double-circuit line non-same-name phase crossover line ground fault. According to the method, fault phase voltage, fault phase current and zero sequence current at the protection installation position of a circuit line I of double circuits on the same tower are firstly measured, a binary search method is adopted, the phase characteristic that phases of relative coefficients before and after the non-same-name phase crossover line ground fault suddenly change to be smaller than zero from phases greater than zero and the amplitude value characteristic that the amplitude values of the relative coefficients at the non-same-name crossover line ground fault point are minimum are comprehensively utilized, so that accurate distance measuring on the double-circuit line non-same-name phase crossover line ground fault is achieved, high capacity for resistance to transition resistance and the load current is achieved, and it is guaranteed that no fault distance measuring dead zones exist when the double-circuit line non-same-name phase crossover line ground fault happens on an outlet in the forward direction. The binary search method is adopted for searching for the non-same-name phase crossover line ground fault point, the calculation amount is one half that of a common one-dimensional search method, and therefore rapid single-ended distance measuring on the double-circuit line non-same-name ground fault is achieved.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for quickly locating double-circuit line non-identical phase cross-line grounding faults by utilizing the amplitude-phase characteristics of relative coefficients. 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 uses the voltage...

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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