Improvements in routine factory tests for partial discharge detection in GIS using pulse discrimination techniques

The accuracy of routine partial discharge testing of GIS sub-assemblies was formerly limited by the use of open terminal transformers and bushings. Consequently, the background interference level was unpredictable and at times too high for measurement to take place at all. The introduction of the Pulse Discrimination System allowed this problem to be reduced. With improved earthing and test circuitry, routine measurements at levels of 3 pC or less and up to 680 kV are feasible