Non-contact multi-point grounding detection method and system for secondary circuit of current transformer

Abstract

The invention relates to a non-contact multi-point grounding detection method and system for a secondary circuit of a current transformer. A changing magnetic field is exerted on a neutral line in a secondary circuit; on the basis of Faraday's law of electromagnetic induction, whether a current is generated in the neutral line is determined; and only when two-point grounding occurs at the secondary circuit is the current generated in the neutral line. And if only one-point grounding occurs at the loop, no current is generated. The system comprises: a signal injection system, which is used for exerting a changing magnetic field perpendicular to the neutral line in the neutral line; a signal acquisition device, which is used for collecting the current of the neutral line; and a data processing and grounding criterion system, which is used for determining whether multi-point grounding occurs. According to the invention, the method and the system can be applied to a transformation substation for determination of current transformer secondary circuit multi-point grounding examination; and on the premise that normal running of the protection device is ensured to be not influenced, whether multi-point grounding occurs at the secondary circuit of the current transformer can be effectively detected.

Description

technical field [0001] The invention relates to a non-contact method and system for detecting the multi-point grounding of a secondary circuit of a current transformer of a substation, belonging to the technical field of electric power automation. Background technique [0002] In the power system, the secondary circuit plays a very important role in ensuring the safe and stable operation of the system. In the normal operation mode of the system, in order to ensure the safety of people and equipment, "Eighteen Major Power Grid Anti-Accident Measures of the State Grid Corporation", " The Electric Work Site Safety Regulations stipulates that an electrical connection of the secondary circuit of the current transformer must have a reliable grounding point. At the same time, in order to ensure the correct operation of relay protection and safety automatic devices, only one grounding point is required in the current loop. However, since the current secondary circuit of the substat...

AI Technical Summary

Problems solved by technology

This method is simple and effective, and can quickly and accurately detect multi-point grounding phenomena, but it needs to be connected in series with a low-voltage signal generator in the original circuit, which is not suitable for large-scale promotion, especially for substations that have already been put into operation

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