Characteristics of the dielectric fluids for medium voltage power capacitors

Fluids used for the impregnation of medium voltage power capacitors made with polypropylene film must exhibit suitable gassing tendency, appropriate compatibility with the film in terms of wettability and limited solvent capacity, but in addition should withstand an endurance test. This test consists of two phases: during the first, repeated voltage impulses are applied which may generate partial discharges, a subsequent overload run insures that soundness of the dielectric is maintained.