Barrier effect on electrical tree growth characteristics in silicone rubber

Reliable power cable systems are necessary for efficient electrical power transmission over a long distance. However, electrical trees could grow in the cable systems, such as the cable insulation, joint and termination, eventually leading to insulation breakdown, therefore requiring serious attention. This paper concentrates on the effects of single-layer and double-layer barriers, which are improved techniques for suppressing electrical tree growth in silicone rubber with ethylene-vinyl acetate (EVA) as the barrier material. A simulation work using the finite element method was carried out on silicone composite with the barrier to study the influence of the barrier distance on the electrical tree propagation due to high electric field stress using a needle-plane electrode configuration. In addition, electric field distributions in silicone rubber with single-layer and double-layer barriers were investigated through experiment and simulation. The results illustrated that the electrical tree growth in the barrier region had been slowed down by the double-layer barrier, and the time to the breakdown had increased significantly.