An accurate measurement method for zero-sequence parameters of ultra-high voltage three-circuit transmission lines on the same tower

Abstract

The invention discloses a novel ultrahigh-voltage same-power three-circuit transmission line zero sequence parameter accurate measurement method. First, the zero sequence voltages and zero sequence currents of the head and tail ends of a same-power three-circuit transmission line are measured at the same time, and the zero sequence voltages and zero sequence currents of the three-circuit line are synchronously sampled using the synchronous timing function of the global positioning system GPS; then, a corresponding differential equation set is obtained through an ultrahigh-voltage same-power three-circuit transmission line model based on distributed parameters; and finally, the zero sequence resistance, zero sequence inductance, zero sequence capacitance parameters of the same-power three-circuit transmission line are obtained through a way of measurement and a calculation method given by the invention. The method of the invention is based on a distributed parameter model, is particularly suitable for zero sequence parameter measurement of ultrahigh-voltage long-distance three-circuit transmission lines, can greatly improve measurement accuracy, and can meet the need of practical engineering measurement.

Description

technical field [0001] The invention relates to a method for accurately measuring zero-sequence parameters of transmission lines, in particular to a method for accurately measuring zero-sequence parameters of three-circuit transmission lines on the same tower. Background technique [0002] The transmission line is an important part of the power system and the carrier of electric energy transmission. Transmission line parameters are important parameters for power flow calculation, short circuit calculation, relay protection setting and fault location. Obtaining high-precision line parameter data is of great significance to the stable operation of the power grid. [0003] The zero-sequence parameters of the transmission line are easily affected by the external environment, such as the geometric shape of the transmission line, current, ambient temperature, wind speed, soil resistivity, lightning protection line erection method, and line path. The depth of the loop current in ...

AI Technical Summary

Problems solved by technology

[0006] The present invention mainly solves the disadvantages existing in the prior art that cannot be used for zero-sequence parameter measurement of long-distance (200km and above) three-circuit transmission lines due to the use of concentrated parameters and ignores distributed capacitance, and also avoids the oversimplification of parameters in existing measurement methods The technical problem of defects that lead to excessive measurement errors; provides a measurement that is not only suitable for ultra-high voltage short-distance zero-sequence parameters, but also for long-distance transmission line zero-sequence parameters; solves the simultaneity problem of remote signal measurement; It can measure the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance parameters of three circuits at one time

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