Certain high charging polymeric materials in transformer oil

Abstract

Polymeric materials, both natural and synthetic, produce static electrification by friction. However, these materials have not been studied well in a flow system with insulating fluids. Since power transformers use certain polymeric materials for conductor insulation, it is a matter of interest whether these materials would produce a charge effect. Polyvinyl formal insulation films are used over the primary conductor strands of transformers. A study was undertaken to understand the flow electrification behavior of this family of polymers. Both polyvinyl formal and polyzinyl butyral formulations were tested, both in the dissolved state, and as a deposited film. Although the polyvinyl formals tested showed negligible charge effects in the dissolved state, many of the polyvinyl butyrals (Butvars) exhibited high charge tendency in transformer oil. The deposited film of Butvars also showed high charging, but the degree of charging of the films showed a reverse order when compared to the charging in the dissolved state.