SF_6气体分解产物带电检测发现GIS设备缺陷及其分析与处理

为研究分析一起电化学传感器法进行六氟化硫(SF_6)气体分解产物带电检测发现的GIS电压互感器设备异常,使用不同的分解产物带电检测方法并结合电气试验和解体检查进行了综合分析。结果表明,该带电检测结果是一种未见报道的SF_6气体中H2体积分数异常现象。不同厂家生产的电化学传感器仪器带电检测结果不准确且差异较大,色谱仪更能准确地检测分析故障气体。该电压互感器缺陷的主要原因是生产时使用了退役变压器硅钢片,带入了变压器油等污染物;同时,制造工艺不完善使铁心磁通异常,铁心过励磁下低能放热导致溶解气体逐步析出,部分变压器油及其余物质分解产生氢气。针对该设备缺陷提出了有效的处理措施,成功处理了缺陷,并对同类设备提供了运维建议。进一步地,提出了SF_6气体分解产物带电检测方法和仪器的改进思路,以帮助SF_6气体绝缘设备和电网安全稳定运行。

Analysis and Treatment of GIS Defect Discovered by Live Detection of SF_6 Decomposition Products

To investigate an abnormal of potential transformer(PT)in gas insulated switchgear(GIS)detected by livedetection of sulfur hexafluoride(SF6)decomposition products,the cause of failure is analyzed combining different de-composition products detection techniques,electric tests and equipment disassembling. The obtained results indi-cate that,the observed abnormal phenomenon is a without reported ultrahigh hydrogen content in SF6. The test re-sults from different electrochemical sensor instruments are quite different,and the data from chromatograph is moreaccurate. The main reason of PT defect is introducing some contaminants such as transformer oil from retired siliconsteel sheets. Meanwhile,under the longtime overheating from over-excitation of the defective iron core,evolution ofdissolved gas or decomposition of transformer oil and other materials result in the abnormal high of hydrogen in SF6.The defect of a PT is treated successfully by treatment suggestions. Some maintenance advices for similar equipmentare proposed. Furthermore,the modified ideas for decomposition products detection techniques and devices and use-ful technical guidance are proposed for security and stability of GIS equipment and power grid.