Study on the dielectric system for oil-free 6kV power capacitors

The use of an oil-free design for 6kV power capacitors has not been realized previously, primarily from an economical point of view. Recently, however, the oil-free design is strongly recom mended for service entrance equipment in buildings and underground commercial facilities from the standpoint of fire prevention. Two insulation systems are feasible for the production of oil free power capacitors, a molded insulation system or a gas insulation system. Based on the resistance to thermal cycling, economy, and ease of handling, we selected the gas insulation system. This paper reports the results of various tests performed to select a dielectric system for high-voltage gas-insulated capacitors. A possible dielectric system for gas-insulated capacitors was considered to be one of the following: 1. CF-type capacitor; A roll of polypropylene (PP) film and alu minum foil, or 2. MF-type capacitor; A roll of metallized PP film.