Dielectric strength measurements of silicone gel

Silicone gels are gaining popularity as insulating materials in electrical applications, owing among others, to their good thermal stability, high elasticity, easy processing and good dielectric properties. In this paper results of dielectric strength measurements performed for a commercially available insulating RTV-2 silicone gel are discussed. Test cells with IEC-60243 compliant parallel plate arranged electrodes were cast in silicone gel and subjected to AC dielectric strength tests. The tests were carried out using a step-by-step voltage increase protocol, and the results are compared with those reported for other electrode configurations and obtained by means of the rapid-rise test protocol. Weibull statistical analysis of the measurement data is performed, and the impact of the test parameters, such as the electrode shape and size, the volume of the stressed material, the electric field distribution and the applied voltage rise protocol on the test results is discussed.