A method for measuring mutual impedance between phases of long-distance UHV double-circuit transmission lines on the same tower

Abstract

The invention discloses a method for measuring mutual impedance between phases of long-distance ultra-high voltage double-circuit transmission lines on the same tower. In the first step, the open-circuit end of the first end of the measured phase is grounded, and the open-circuit end of the first end of the other phases is grounded, and the voltage injection current is applied to the first end of the measured phase, and the current signal of the first end of the measured phase and the first end of the other phase at two frequencies are measured synchronously. In the second step, the voltage and current signals at the two frequencies are obtained by using the FFT Fourier transform filtering algorithm; in the third step, the voltage and current signals at the two frequencies are calculated separately to obtain the two frequencies The phase-to-phase mutual impedance value of the two phase-to-phase mutual impedance values ​​is averaged to obtain the phase-to-phase mutual impedance value at a frequency of 50 Hz. The invention changes the traditional measurement method, and considers the influence of line distribution parameter characteristics and induced voltage phases and the existence of power frequency interference on the connection mode and algorithm, especially in long-distance transmission lines, the phase-to-phase measured by the method of the invention The mutual impedance value reduces the error and meets the needs of the project.

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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