Grounding electrode wire fault monitoring method based on high frequency current injection

Abstract

The invention discloses a grounding electrode wire fault monitoring method based on high frequency current injection. The method comprises the steps of: injecting high frequency current signals to a head end of a grounding electrode wire, wherein the frequency of the high frequency current signals meets an inequation shown in the specification, lT is the length of the grounding electrode wire, fin is the frequency of the high frequency current signals, L1 is the inductance of per unit length of the grounding electrode wire, and C1 is the capacitance of per unit length of the grounding electrode wire; measuring co-frequency voltage signals of the head end of the grounding electrode wire while injecting the high frequency current signals; according to the fact that the module value of grounding electrode wire measuring impedance is equal to the ratio of the amplitude of the co-frequency voltage signals to the amplitude of the high frequency current signals, obtaining the module value of grounding electrode wire measuring impedance; and if the module value of grounding electrode wire measuring impedance is smaller than a setting value, determining that the grounding electrode wire has a fault. According to the invention, the frequency selection range of the injected high frequency current signals is given, and in the range, the law that the grounding electrode wire measuring impedance is monotonously increased with the increasing of the fault distance is ensured.

Description

technical field [0001] The invention relates to the technical field of ultra-high voltage direct current transmission line monitoring, in particular to a method for monitoring ground electrode lead wire faults based on high-frequency current injection. Background technique [0002] UHVDC transmission technology has the advantages of large transmission capacity, long transmission distance, and strong control performance, and plays a pivotal role in the long-distance transmission of electric energy and the interconnection of regional power grids. The grounding electrode is an important part of the UHV DC transmission system, and it mainly plays the role of providing a return path to the earth and establishing a system voltage reference point. With the continuous construction and operation of UHVDC transmission projects, the selection of the pole location of the grounding pole is becoming more and more difficult. At the same time, considering the influence of DC bias on the equ...

AI Technical Summary

Problems solved by technology

[0005] What the present invention aims to solve is the problem of low reliability in monitoring UHVDC ground electrode lead wire faults based on the injection method in the prior art

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