Voltage Measurement Method of Phase-to-Phase Short-circuit Fault Point of Transmission Line

Abstract

The invention discloses a method for measuring voltage at a interphase short circuit fault point of a power transmission line. The method comprises the steps as follows: fault interphase voltage, a fault interphase negative-sequence current and a fault interphase current in a power transmission line protection installation position are measured; a real part of the ratio of the fault interphase voltage to the fault interphase negative-sequence current is calculated; a real part of the ratio of the power transmission line voltage drop per unit length to the fault interphase negative-sequence current is calculated; and the fault interphase negative-sequence current is multiplied by the difference between the real part of the ratio of the fault interphase voltage to the fault interphase negative-sequence current and the real part of the ratio of the power transmission line voltage drop per unit length to the fault interphase negative-sequence current, so that the voltage at the interphase short circuit fault point of the power transmission line is obtained. According to the method, the accurate measurement of the voltage at the interphase short circuit fault point of the power transmission line is realized by virtue of the single-ended electrical capacity, the measurement accuracy is not influenced by a fault position, transition resistance and a load current, the algorithm principle is simple, the calculation capacity is small, and the measurement real-time performance is high.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for measuring the voltage at a short-circuit fault point between phases of a transmission line. Background technique [0002] Through the real-time measurement of the voltage of the phase-to-phase short-circuit fault point of the transmission line, it is beneficial to grasp the influence of the phase-to-phase short-circuit fault on the thermal and dynamic stability of the transmission line in time, and provide a reliable decision-making basis for ensuring the safety of the transmission line and the stable operation of the power grid. [0003] Through the real-time measurement of the voltage of the phase-to-phase short-circuit fault point of the transmission line, online diagnosis can be made on the type of low-, medium-, and high-resistance phase-to-phase short-circuit faults of the transmission line according to the voltage amplitude of the...

AI Technical Summary

Problems solved by technology

[0004] However, in the field of relay protection technology, there is still a lack of a measurement method that can accurately calculate the voltage at the fault point of the phase-to-phase short-circuit of the transmission line. It is also unable to provide a scientific basis for the diagnosis of low-, medium-, and high-resistance phase-to-phase short-circuit fault types of transmission lines.

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