Investigation of PRPD During Electrical Tree Initiation and Growth in a Needle-free Void Geometry

A needle-free geometry has been developed to produce electrical tree initiation and growth using an engineered void and interface between epoxy resin and silicone rubber. A rod electrode of 4 mm diameter is embedded in the silicone rubber, with a controlled void at its flat end, and 12 kV is applied. Treeing and tracking activities are observed along the epoxy silicone interface and within the epoxy bulk. The dependence of partial discharge (PD) measurements on track development is also studied. Phase-resolved PD patterns are used to compare and understand PD behavior during testing. The geometry used is capable of generating electrical tree growth without the recourse to needle electrodes, and is therefore more representative of damage in high voltage equipment than most laboratory grown trees.