油浸式电流互感器膨胀器异常变形的故障分析

Fault Analysis of Abnormal Deformation of Oil-immersed Current Transformer Expander

油浸式电流互感器在电力系统得到广泛的应用,其金属膨胀器起到补偿油位体积与压力释放的作用。本文作者以同一厂家同型号同批次油浸正立式电流互感器膨胀器异常变形顶起的两起案例为例,通过解体前的油色谱、局部放电、高电压介损等试验,确定故障类型。结合解体检查过程中未发现过热和放电痕迹,发现内部电容屏局部褶皱,分析内部油色谱异常的主要原因为生产厂家制造工艺不严,导致电容屏之间存在局部褶皱或是绝缘纸受潮,进而导致过热与局部放电并产生大量气体H2和总烃,为电流互感器膨胀器变形的故障分析提供一定指导意见。

The oil-immersed current transformer is widely used in the power system, and its metal expander plays a role in compensating the oil level volume and pressure release. In this paper, two cases of expander abnormal deformation of the same type and batch of oil-immersed vertical current transformer from the same manufacturer are taken as examples, and the types of defects are determined by oil chromatography, partial discharge, high-voltage dielectric loss and other tests before disintegration. Combined with the fact that no overheating and discharge traces are found during the disassembly inspection, the local wrinkles of the internal capacitance screen are found, and the main reason for the abnormal internal oil chromatography is that the manufacturer's manufacturing process is not strict, resulting in local wrinkles between the capacitance screens or damp insulation paper, which in turn led to overheating and partial discharge and produces a large amount of gas such as H2and total hydrocarbons. It provides some guidance for the fault analysis of current transformer expander deformation.