Double-circuit line different phase overline grounding fault single-terminal location method

Abstract

The invention discloses a double-circuit line different phase overline grounding fault single-terminal location method, which comprises the following steps of calculating a zero-sequence current phase angle of an II circuit transmission line of a double-circuit parallel transmission line; calculating zero-sequence current of the II circuit transmission line of the double-circuit parallel transmission line; calculating grounding fault point voltage of a I circuit transmission line of the double-circuit parallel transmission line; calculating the line distance from a protection setting range of the I circuit transmission line of the double-circuit parallel transmission line to a grounding fault point; then utilizing a protection setting range to minus the line distance from the protection setting range of the I circuit transmission line of the double-circuit parallel transmission line to the grounding fault point, and obtaining a fault distance from a protection installation part of the I circuit transmission line of the double-circuit parallel transmission line to the grounding fault point. The method considers the influences of zero mutual inductance between lines, eliminates the influences of zero mutual inductance between the lines on double-circuit parallel transmission line different phase overline grounding fault single-terminal location 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 double-circuit line non-identical phase cross-line grounding faults. 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 and current data at one end of the transmission line to determine the f...

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. During distance measurement, the distance measurement accuracy is seriously affected by the fault point transition resistance 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 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 has no ranging result, and cannot provide accurate fault location information. , resulting in difficulty in line fault line inspection, which is not conducive to rapid troubleshooting and rapid restoration of line power supply

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