一起超高压变电站低抗绝缘油检测异常缺陷分析
王从刚，钱苗旺，郁飞
(国网江苏省电力有限公司连云港供电分公司，江苏 连云港 222000)
摘 要：针对一起在超高压变电站油浸式低压并联电抗器 (低抗) 绝缘油检测中发现总烃超标的事故，通过对绝缘油溶解气体含量分析，借助三比值法初步推断低抗内部存在中温过热故障，进行包含直流电阻、绝缘电阻、阻抗、介损及电容量等项目的诊断性试验，分析低抗缺陷原因，并对低抗进行解体验证。结果表明，低抗缺陷的原因为接地屏中存在铜箔片异常搭接，进而引起环流引发局部过热，造成异常搭接处被灼烧，导致总烃超标。
关键词： 变电站；油浸式低压并联电抗器；总烃；过热故障；缺陷分析
中图分类号：TM472 ；TM855 文献标识码：B 文章编号：1007-3175(2023)02-0047-04
Analysis on Abnormal Detection of Low-Voltage Parallel Reactor
Insulating Oil of a Ultra-High Voltage Substation
WANG Cong-gang, QIAN Miao-wang, YU Fei
（Lianyungang Power Supply Branch, State Grid Jiangsu Electric Power Co., Ltd, Lianyungang 222000, China）
Abstract: An accident which the total hydrocarbon from insulating oil of the oil-immersed low-voltage parallel reactor of a ultra-high voltage substation exceeded standard happened, so the paper analyzes the dissolved gas content of insulating oil, and it is preliminarily inferred through three-ratio method that medium temperature overheat fault exists inside of the low-voltage parallel reactor. Then, diagnostic tests are conducted on DC resistance, insulation resistance, impedance, medium loss, and capacitance to analyze why the low-voltage parallel reactor has defects, and disassembling the low-voltage parallel reactor verifies the correctness of this analysis. According to the results, the reason for defects of the low-voltage parallel reactor is that copper foils in the earthing panel are connected abnormally. As a consequence, circulating current contributes to local overheating and the abnormal connection burns, causing the total hydrocarbon exceeding standard.
Key words: substation; oil-immersed low-voltage parallel reactor; total hydrocarbon; overheat fault; defect analysis
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