Method of achieving interphase short circuit fault distance measurement of line by means of single-end electric quantities

Abstract

The invention discloses a method of achieving interphase short circuit fault distance measurement of a line by means of single-end electric quantities. The method includes measuring fault interphase voltage, fault interphase currents and fault interphase negative-sequence currents on a protective installation portion of a power transmission line, calculating an imaginary part of a ratio of the fault interphase voltage and the fault interphase negative-sequence currents, calculating an imaginary part of a ratio of voltage drop of the power transmission line per unit length and the fault interphase negative-sequence currents, dividing the imaginary part of the ratio of the voltage drop of the power transmission line per unit length and the fault interphase negative-sequence currents by the imaginary part of the ratio of the fault interphase voltage and the fault interphase negative-sequence currents, and obtaining a fault distance from the protective installation portion of the power transmission line to an interphase short circuit fault point. The method achieves precise measurement of the interphase short circuit fault distance of the power transmission line by means of the single-end electric quantities, and eliminates influences of transition resistance and load currents on measurement precision of the fault distance. Distance measuring principles are simple, programs are easy to achieve, operation amount is little, the distance measuring speed is high, and instantaneity is strong.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for measuring distance between phase-to-phase short-circuit faults of lines by using single-ended electrical quantities. Background technique [0002] The single-end fault location method of transmission lines only uses the electrical quantity at one end of the transmission line for fault location, does not require communication and data synchronization equipment, has low operating costs and stable algorithms, and has been widely used in transmission lines. Single-ended fault location methods are mainly divided into traveling wave method and impedance method. The traveling wave method utilizes the transmission properties of fault transient traveling waves to perform single-ended fault location. It has high precision and is not affected by the operation mode and excessive resistance. However, it requires a high sampling rate, requires a spec...

AI Technical Summary

Problems solved by technology

The traveling wave method utilizes the transmission properties of fault transient traveling waves to perform single-ended fault location. It has high precision and is not affected by the operation mode and excessive resistance. However, it requires a high sampling rate, requires a special wave recording device, and has high application costs.

The impedance method uses the voltage and current after the fault to calculate the fault loop impedance, and performs single-ended fault distance measurement according to the characteristic that the line length is proportional to the impedance. It is simple and reliable, but the distance measurement accuracy is seriously affected by the transition resistance, especially when the transition resistance is large In this case, the single-ended fault location results will seriously deviate from the real fault distance, and even exceed the total length of the transmission line, so that the single-ended fault location results lose their reference value and cannot provide accurate and effective fault location information for power system fault line inspectors. Facilitate rapid fault location finding and troubleshooting

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