Single-ended ranging method for non-identical phase-cross-line grounding faults of double-circuit lines

Abstract

The invention discloses different-phase cross-line ground fault single-terminal location method for double-circuit lines. Firstly, the fault phase voltage, the fault phase current and the zero-sequence current at the protection installation position of the circuit line I of the double-circuit lines on the same pole are measured, the zero-sequence compensation current of the circuit line I of the double-circuit lines on the same pole is calculated according to influences of zero-sequence mutual induction between the lines, voltage of a different-phase cross-line ground fault point of the double-circuit lines is calculated, the angle of voltage drop from the protection installation position of the circuit line I of the double-circuit lines on the same pole to the different-phase cross-line ground fault point of the double-circuit lines is calculated in a one-dimension searching method after dropping of voltage from each point on the circuit line I of the double-circuit lines on the same pole to the different-phase cross-line ground fault point of the double-circuit lines, precise distance measurement of different-phase cross-line ground faults of the double-circuit lines is achieved by means of the along-line voltage drop phase characteristics, influences of zero-sequence mutual induction between the lines, transition resistance and load currents on fault distance measurement precision are eliminated, and high capacity of resisting influences of the transition resistance and load currents is achieved.

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 a double-circuit line with a non-identical phase cross-line grounding fault based on the voltage drop phase characteristic along the line. 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 a...

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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