Design and Analysis of SMES-ETM Electrical Insulation

Abstract

The mechanical design and the electrical field analysis of the Ebasco/Westinghouse SMES-ETM coil electrical insulation system are presented. The electrical insulation design of the coil includes the turn to turn, layer to layer, and between the coil to the wall of the liquid helium vessel of the cryostat. A finite element analysis code (WEMAP) was used to obtain detailed electrical field plots of the high electrically stressed regions of the coil. These analytical results were used in conjunction with the experimental data of dielectric breakdown, available in the literature or obtained by in-house testing, to determine the optimum configuration and materials of the insulation spacers. An adequate design safety factor between the insulation capability and the maximum operating electrical stress was adopted to ensure the design integrity under all operating conditions and to allow for the uncertainties of the experimental dielectric breakdown data.