微水对SF_(6)气体工频击穿特性影响的实验研究

Experimental Study of the Effect of Micro-Water on the Frequency Breakdown Characteristics of SF_(6)Gases

运行在工频电压条件下的气体绝缘全封闭组合电器(GIS)受到微量水分侵入时会严重降低气室内SF_(6)气体的绝缘性能,影响高压电器设备安全运行。为此,自主设计了GIS绝缘结构实验装置,并搭建了气体放电实验平台,通过控制电极微水体积分数、气压以及电极间隙距离,对SF_(6)气体在稍不均匀电场下的工频击穿特性进行实验研究。研究发现:在稍不均匀电场中,SF_(6)气体工频绝缘性能随微水体积分数的增大呈下降趋势;气压范围在0.4~0.6 MPa时,微水体积分数超过800μL/L后,随着其增大SF_(6)气体工频击穿电压下降较为明显;在相同气压下,电极间隙距离越大,微水体积分数增大对SF_(6)气体工频绝缘性能的影响越大。根据实验结果,建议在工频电压下,设备运行温度为15℃时,0.4 MPa和0.5、0.6 MPa下气体绝缘设备中水分体积分数限值分别为450μL/L和250μL/L。

When the GIS operating under industrial frequency voltage is invaded by trace water,the insulating property of SF_(6)gas inside the gas chamber will be seriously reduced,which will affect the safe operation of high-voltage electrical equipment.For this reason,the GIS insulation structure experimental device is designed independently,and the frequency experimental research on SF_(6)gas under slightly uneven electric field is carried out by constructing the gas discharge experimental platform and controlling the distance of the discharge gap,air pressure and different micro-water content.The results show in a slightly uneven electric field,the frequency insulation performance of SF_(6)gas decreases with the increase of micro-water content;when the gas pressure is set to 0.4~0.6 MPa,the micro-water content is more than 800μL/L,and the frequency breakdown voltage of SF_(6)gas decreases more obviously;under the same gas pressure,the larger the gap distance is,the effect of micro-water content on the frequency insulation performance of SF_(6)gas is the more obvious.In addition,based on the experimental results,450μL/L and 250μL/L were suggested as the moisture control limits at 0.4 MPa,0.5 and 0.6 MPa at 15℃,respectively,under the IFV voltage.