Method and system for eliminating mutual inductance between leads in ground resistance measurement

Abstract

The invention relates to a method and a system for eliminating mutual inductance between leads in ground resistance measurement. By synchronously measuring measurement voltage and current waveform and analyzing the amplitude ratio of voltage to current and the phase angle difference between the voltage and the current, ground impedance under a given frequency and an impedance angle of the ground impedance can be obtained, the mutual inductance between the leads of a voltage electrode and a current electrode in measurement is obtained by calculation, and a true value of the ground impedance can be obtained by subtracting a part generated by the mutual inductance from the ground impedance on the basis. According to a testing method, the influence caused by various background interference signals is effectively avoided, and an accurate measurement result can be obtained even if the output current is very low. According to the method for eliminating the mutual inductance between the leads in the ground resistance measurement, the test pay-off workload is small, and a voltage lead and a current lead can be paved abreast. Test data can be acquired and analyzed under the automatic control of a portable system without manual intervention, and the characteristic of simplicity in operation is achieved. The data are directly analyzed on the scene by virtue of the portable system, the visualization is high, and industrial frequency ground resistance can be immediately given.

Description

technical field [0001] The present invention relates to the field of high-voltage technology, in particular to a method and system for eliminating the mutual inductance of lead wires in ground resistance measurement, which is used to measure the power frequency ground resistance of substations and power plants, especially when the distance between current and voltage lead wires is close and the lead wires The mutual inductance between them has a strong influence on the test results. Background technique [0002] The power frequency grounding resistance value is an important technical index of the grounding system of the power generation substation. It is an important parameter to confirm the effectiveness and safety of the grounding system and to identify whether the grounding system meets the design requirements. The measurement of the power frequency grounding resistance of the grounding grid is the most important means to check the acceptance and operation of the groundin...

AI Technical Summary

Problems solved by technology

At this time, the mutual inductance between the two leads is very strong, and the AC measurement current transmitted on the current electrode lead will induce a high voltage on the voltage lead, which will affect the final test result

[0004] At present, those skilled in the art use the included angle method to reduce the influence of the mutual inductance between the voltage electrode and current electrode leads. The angle between the voltage electrode lead and the current electrode lead is 90 degrees or even larger, but at this time the voltage reference point Not a valid reference point, the measurement results need to be corrected, and other new errors will be introduced

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