Partial discharges at different voltage waveshapes: Comparison between two different acquisition systems

In modern HV apparatuses the wide use of electronic converters, increase the stress on the involved insulation systems and thus affect the reliability of the whole power grid. Additionally, such non-sinusoidal voltage shapes contain high gradient flanks that create problems in the detection of partial discharge (PD) activity. The aim of this paper is to discuss the methodology on how to suitably approach PD detection in insulation systems exposed to various voltage waveshapes in general by comparing two different measuring systems. The first one, equipped with a resonant PD decoupler, designed specifically for detection at typical power electronic waveshapes and the other one, based on an antenna sensor with flat frequency response, a general-purpose AC system. It was found that not so much the acquisition principles as the features are important for effective detection of PD signals appearing at rapidly changing test voltages from power electronic devices.