by Pia Lindorf and Corina Neumeister, Nabaltec AG
High temperature vulcanization (HTV) silicone rubber is the polymer of choice with regard to housing material for high voltage applications. The requirements are challenging due to harsh environmental conditions like UV irradiation, humidity, industrial pollution, etc. The tracking and erosion performance of the compound needs to be evaluated to ensure the long term performance of the high voltage insulator. Another key aspect to increase the durability of the insulator is the resistance against nitric acid, as this is formed by a combination of unavoidable corona discharges in overhead power lines and atmospheric humidity.