Life estimation for long rod composite insulators subjected to accelerating ageing by combined static and cyclic loading

Influence of the position of fatigue characteristics on the cyclic load L versus time t plots on the long-term mechanical strength has been analyzed for long rod composite insulators, on the basis of experimental data. A procedure has been presented for forecasting mechanical durability of composite insulators from determined fatigue characteristics, for any given maximum cyclic loads and load amplitudes. It has been shown that long rod composite insulators of good manufacturing quality maintain their electric properties practically until their failure during the fatigue test.