Electrical testing of rubber coatings and comparison with resin based coatings for use in 25 kV insulators on B.R. (TM-ETR-081)

Rubber coatings have been used to protect 25 kV glass fibre insulators on B.R. from discharge damage since 1966. Although butyl rubber has been preferred to filled silicone rubbers due to lower cost both systems possess hydrophobic properties which prevent surface current and damaging discharge from occurring. Only when heavy...