Single-end distance measurement method for single-phase grounding fault of double-circuit lines paralleled on the same pole by using single-end electric quantity of single-circuit lines

Abstract

The invention discloses a double-circuit-on-same-tower double-circuit line single-phase grounding fault single-end distance measurement method implemented by using the single-end electrical quantity of a single-circuit line. A fixed step length is increased gradually in sequence from the protection mounting position of the I-circuit line of the double-circuit-on-same-tower double-circuit line by adopting a one-dimensional searching method so as to calculate phase angles of negative-sequence current of an operating voltage leading fault phase at each point of the I-circuit line of the double-circuit-on-same-tower double-circuit line until the full length of the I-circuit line of the double-circuit-on-same-tower double-circuit line is completed; the phase angle of the negative-sequence current of the operating voltage leading fault phase at a certain point is dropped within the range of (0 degree, 180 degrees), and the phase angle of the negative-sequence current of the operating voltage leading fault phase at the next adjacent point is dropped within the range of (180 degrees, 360 degrees), so that the middle position between the two points is a fault point. According to the method, the influence of the interline zero-sequence mutual inductance is metered, so that the influence of the interline zero-sequence mutual inductance on the single-end distance measuring precision of the single-phase grounding fault of the double-circuit-on-same-tower double-circuit line is eliminated.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-terminal distance measuring method for single-phase grounding faults of parallel double-circuit lines on the same pole by using the single-end electrical quantity of single-circuit 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 ranging method is a method th...

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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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