Prediction of the thermal runaway temperature for cap and pin porcelain insulator

The heat conduction inside a porcelain conical head insulator has been simulated and used to estimate the insulator thermal runaway critical ambient temperature under various voltages. The simulation results are compared with measured results. They show that the thermal runaway occurs at the top of the porcelain insulator head. On the basis of this investigation test conditions are established and a simplified test procedure for DC insulators is suggested.<>