Analysis of Abnormal Secondary Voltage of 500 KV HGIS Line
DOI:
https://doi.org/10.71222/z79kej48Keywords:
HGIS, PT, voltage circuit, sampling anomalyAbstract
A 500kV HGIS line experienced an abnormal voltage data alarm for the 3U0 voltage. Through on-site sampling verification, loop temperature measurement, and theoretical analysis, it was determined that a grounding fault existed in the secondary internal circuit of the line voltage transformer (PT), causing abnormal secondary voltage sampling outputs from two sets of line protection systems. This article provides a detailed account of the abnormal event, on-site inspection findings, fault cause analysis, and the results of the return-to-factory inspection, along with proposed corrective measures. The aim is to provide a reference for the investigation and prevention of similar issues.
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