Problems and new solutions for partial discharge measurement on high voltage cables under noisy conditions

This paper reports about problems and new solutions concerning partial discharge (PD) measurement on high voltage cables under noisy conditions. In addition to the problems of PD measurement on high voltage cables in laboratories there are many problems for on-site PD measurement caused by ambient noises. Some suitable solutions according to these problems are introduced. The decoupling of the measuring signal is realized successfully with a Rogowski coil and a special cylindrical voltage sensor. A personal computer receives the digitized measuring signal and enables a digital signal processing. The necessary noise rejection is accomplished by well matched analogue coarse filters and digital filter algorithms, which suppress continuous noise signals. Experimental investigations carried out in the laboratory and on a layed cable track show the effectiveness of the presented PD measuring system under noisy conditions