液体介质中局部放电的测量方法研究

Measurements of Partial Discharges in Liquids

介绍法国电力公司研发部和法国国家科研中心静电和绝缘材料实验室联合进行的液体介质中局部放电测量方法研究。该研究旨在说明使用不同频率检测器时矿物油中局部放电测量值的变化及反应等问题。相对于其它介质,液体中的放电现象持续时间长得多,因此必须采用适当的测量技术。然而,在具体的应用实践中通常是办不到的。在本研究中,进行了各种试验和计算,以确定在液体局部放电中各种频率响应的传统RLC阻抗电路的典型缺陷。试验包括矿物油中的电晕和爬电现象,并与空气中的火花放电比较。结果表明,标定高频局部放电测量系统时,在液体中测量的放电电荷与实际电荷的比率较气体中的低得多。如果试验在可能包括各种类型局部放电源的实际装置上进行,相对于其它放电类型,高频测量系统在液体中的放电将被大大低估。这个偏差随测量系统的频率响应的增加而增加。

Researches on measurements of Partial Discharges(PD) in liquids conducted jointly by Research and Develop- ment Division of Electricite de France and Laboratory for Electrostatics and Dielectric Materials(LEMD) are introduced in this porper. These researches aimed at explaing the variations and significance of PD measurements in mineral oil, when detectors with different frequency response are used. The conclusions of the investigations are the reliable quantitative PD measurement of discharges in liquids requires specific measuremtnt parameters, i.e. long intergration times. If not, dis- charges in liquids will be strongly underestimated. So, the interpretation of PD measurements in liquids using classical measurement methods should be treated with great care. Moreover, high frequency measurement devices are not adequate to measure discharges in liquids.