变压器的UHF法局放故障定位初探

Preliminary Research on the Feasibility of PD Location in Power Transformer Using UHF

分析变压器中主要结构部件对UHF电磁波传播影响后提出了基于最短光程原理定位变压器局放故障的思路。用模拟局放源和金属障碍物、变压器绕组试验研究UHF信号传播路径长度与传播时间关系的结果表明:存在金属障碍物时电磁波传播时延大于理论值,具体误差与信号传播路径上障碍物的遮挡范围有关;绕组的油道结构对信号虽有一定衰减,但对传播时延基本无影响,信号可穿透绕组以近直线传播。

The influences of main transformer components on the propagation characteristics of UHF wave are analysed. The idea of PD location based on the shortest optical path principle is introduced, and key problems of PD location are discussed. Experiments on the relationship between the shortest path length and time-flight of UHF signals have been performed using basic geometric conducting obstacles and real transformer coil, the results indicate that solid conducting obstacles can result in longer measured time-flight than theoretical value, while transformer coil can do certain attenuation to the PD signal, but bring little delay to the time-flight, which means that UHF signal can penetrate oil-gap of winding and propagate along straight line approximately.