A New Impregnant for HV Power Capacitors

The main properties of a newly developed impregnant ant for high voltage power capacitors are given. This new liquid, a mono dibenzyltoluene blend (M/DBT), has a very high degree of aromaticity. The results of many tests carried out both on model and large capacitors are reported. A screening test using a transparent micro-model of an all-film capacitor has been used to study the properties of the fluid when submitted to very high electrical stresses resulting from transient overvoltages at low temperature. re. The correlation between the results obtained with micro-models and with real capacitors are reported. Partial discharge extinction ability of M/DBT is compared to that of liquids being used at present for this application. The authors describe the laboratory test that they have developed to evaluate the performances of the polypropylene filmliquid iquid insulation at high temperature. Using this test, the influence of many parameters is studied. They cast new light on all-film capacitor technology.