Method for measuring phase to phase mutual impedance of long-distance extra-high voltage common-tower double-circuit transmission line

Abstract

The invention discloses a method for measuring phase to phase mutual impedance of a long-distance extra-high voltage common-tower double-circuit transmission line. The method comprises the first step that the head end of a measured phase is in an open circuit, the tail end of the measured phase is in ground connection, the head ends of other phases are in an open circuit, the tail ends of other phases are in ground connection, voltages are applied to the head end of the measured phase, currents are injected into the head end of the measured phase, and the current signal of the head end of the measured phase and the induction voltage signals of the head ends of other phases under two frequencies are synchronously measured; the second step that the voltage signals and the current signals under the two frequencies are obtained through an FFT filtering algorithm; the third step that phase to phase mutual impedance values under the two frequencies are respectively calculated according to the voltage signals and the current signals under the two frequencies, and a phase to phase mutual impedance value under the frequency of 50Hz is obtained by averaging the two phase to phase mutual impedance values. According to the method, a traditional measurement method is changed, the influence of line distribution parameter characteristics and induction voltage phases and the existence of power frequency interference are considered in the line connection mode and the algorithm, and especially in the long-distance transmission line, the errors of the phase to phase mutual impedance value measured through the method are reduced, and engineering needs are met.

Description

technical field [0001] The invention belongs to power transmission and transformation testing, and in particular relates to a method for measuring the mutual impedance between phases of a long-distance ultra-high voltage double-circuit transmission line on the same tower. Background technique [0002] For the measurement of mutual impedance between phases of long-distance double-circuit transmission lines on the same tower, traditional measurement methods often produce large errors due to the mutual influence of line phase conductor capacitance and impedance and the existence of power frequency interference. The longer the line distance, the greater the error , such errors may not be tolerated in engineering applications. Contents of the invention [0003] The purpose of the present invention is to propose a technical scheme for measuring mutual impedance between phases of long-distance ultra-high voltage double-circuit transmission lines on the same tower. In the scheme, ...

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Problems solved by technology

[0003] The purpose of the present invention is to propose a technical scheme for measuring mutual impedance between phases of long-distance ultra-high voltage double-circuit transmission lines on the same tower. In the scheme, different frequency power supply is used to solve the problem of power frequency interference, and the mutual impedance between phases of long-distance lines is used to correct The algorithm overcomes the influence of phase-to-phase capacitance and ground capacitance on the mutual impedance between phases, and this method is applicable to the measurement of mutual impedance between lines with different lengths

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