Partial discharge measurement and gas monitoring of a power transformer on-site

In this paper, the observation of a power transformer in a substation with the help of gas monitoring and Partial Discharge (PD) measurement on-site is described. For the gas monitoring, a measuring system is installed, which records continuously the appearing undissolved gases of the transformer with a high resolution. Thus, it is possible to observe the gassing activity of the transformer accurately enough for an assessment. The simultaneous PD measurement is conducted with a broadband measuring system. The signals are digitized and filtered to suppress the continuous, sinusoidal noises. Afterwards, the pulse shaped noises synchronous to the main are suppressed via an adaptive algorithm. The separation of the PD from the stochastically appearing pulse shaped noises takes place with the help of directional coupling and pattern recognition algorithms