Harmonic-component-based anti-interference capacitance measurement method for untransposed transmission line

Abstract

The invention discloses a harmonic-component-based anti-interference capacitance measurement method for an untransposed transmission line. Big enough third harmonic is generated in a measurement line through a saturable transformer, a GPS-based synchronous measuring unit is utilized to measure the triphase voltage and the triphase current at the head end and the tail end of the line, and the Hanning windowed FFT interpolation algorithm is adopted to treat the voltage and the current at the head end and the tail end of the line so as to obtain triple harmonic components of the triphase voltage and the triphase current at the head end and the tail end. Meanwhile, in consideration of unequal mutual parameters between two phases of the untransposed transmission line, the harmonic components are utilized to solve the self-admittance and interphase transadmittance parameters of all phases based on a lumped parameter model of the transmission line, and all-sequence capacitance parameters are obtained. The harmonic-component-based anti-interference capacitance measurement method eliminates influence on capacitance measurement of a measured line from power frequency interference of a nearby charged operation line, greatly improves the measurement accuracy and can meet the demands of actual project measurement.

Description

Technical field [0001] The invention relates to a method for accurately measuring capacitance parameters of a transmission line, and the content is a non-transposed transmission line capacitance anti-interference measurement method based on harmonic components. Background technique [0002] Transmission line parameters are important basic data for power flow calculation, power loss calculation, short circuit calculation, fault analysis and relay protection setting calculation in the power system. Without accurate line parameters, the accuracy of the above calculation cannot be guaranteed, which may lead to non-operation or malfunction of the relay protection device and other automatic devices. Therefore, accurately obtaining the parameters of the transmission line is of great significance to the normal operation of the power system. [0003] With the rapid development of the power system in recent years, due to the congestion of transmission corridors and the high construction cos...

AI Technical Summary

Problems solved by technology

[0005] However, in the actual measurement, most of the transmission lines below 200km are non-transposition lines, resulting in enhanced interference between non-transposition lines, because the induced voltage phasors of other nearby non-transposition lines on the measurement line are different from each other. zero

Especially in a strong interference environment, the nearby coupling line will induce a large power frequency voltage on the measurement line, that is, power frequency interference, which will bring a large error to the measurement of line power frequency parameters

[0006] Since the interference voltage will change with the power flow of nearby lines, and the interference current caused by the interference voltage cannot be measured, it is difficult to incorporate the interference voltage and interference current into the calculation formula in practice

In the actual measurement of the vast majority of capacitance parameters, a measurement method that does not consider interference is used, resulting in large measurement errors, which cannot meet the actual engineering measurement needs

Images