Large grounded screen power-frequency grounding impedance measurement method based on multiple-synchronous different-frequency method

Abstract

The invention discloses a large grounded screen power-frequency grounding impedance measurement method based on a multiple-synchronous different-frequency method. The Large grounded screen power-frequency grounding impedance measurement method specifically includes, by a multiple synchronous measurement method, synchronously measuring multiple groups of different-frequency voltages and different-frequency currents in the process of measuring large grounded screen power-frequency grounding impedance through the different-frequency method; calculating to obtain multiple groups of different-frequency voltage phasors and multiple different-frequency current phasors by means of a windowed Fourier transform filter algorithm; calculating the grounding impedance of the large grounded screen under different frequency through a designated computing method; and calculating the grounding impedance, including resistive component and inductive component, of the large grounded screen under power frequency by an interpolation method. In the large grounded screen power-frequency grounding impedance measurement method, influences of electromagnetic coupling effects between current electrode lead and voltage electrode lead and between parallel overhead lines of a neutral-point grounding system surrounding a measurement circuit and the voltage electrode lead to measurement results are taken into consideration when an outage line is utilized as the measurement circuit for measurement of the large grounded screen grounding impedance, thus precision of the measurement results of the large grounded screen power-frequency grounding impedance is improved greatly.

Description

technical field [0001] The invention belongs to the technical field of power frequency grounding impedance measurement of power system grounding network, and in particular relates to a large-scale grounding network power frequency grounding impedance measurement method based on a multi-time synchronous different frequency method. Background technique [0002] Grounding resistance is an important technical index of the substation grounding system, and its grounding resistance value must be measured before the substation is put into operation or after a period of operation. Accurately measuring the grounding resistance of the substation grounding grid is one of the important measures to maintain the safe and reliable operation of the power system and ensure the safety of equipment and personal safety. Most of the current practical grounding resistance measurement methods cannot effectively eliminate the error caused by the interference voltage on the voltage electrode lead to ...

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Problems solved by technology

[0005] The present invention mainly solves the problems existing in the prior art that the electromagnetic coupling between the current pole lead wire and the voltage pole lead wire cannot be well handled when measuring the power frequency grounding resistance of a large-scale ground network and the parallel overhead of the neutral point grounding system around the measurement loop. The technical problem of the influence of the electromagnetic coupling between the line and the voltage pole lead on the measurement results; provides a consideration of the current pole lead, the electromagnetic coupling between the parallel overhead line and the voltage pole lead of the neutral point grounding system around the measurement circuit Effect on the measurement results, thus greatly improving the accuracy of large-scale ground network power frequency ground impedance measurement results. The large-scale ground network power frequency ground impedance measurement method based on multiple synchronous different frequency method

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