Insulation failure assessment under random energization overvoltages

This paper offers a new simple approach to the evaluation of the risk of failure of external insulation in view of their known probabilistic nature. This is applied to EHV transmission systems subjected to energization overvoltages. The randomness, both in the applied stresses and insulation's withstand characteristics are numerically simulated and then integrated to assess the risk of failure. Overvoltage control methods are accounted for, such as the use of preinsertion breaker resistors, series capacitive compensation, and the installation of shunt reactors.