A new statistical and optimum approach to lightning insulation coordination of substations

Abstract

With emphasis on the systematic simulation of the lightning transient for substation surge protection, the sensitivity analysis of the overvoltage responses is performed considering the influence of the modelling parameters, lightning random variables, and protective measures, etc. On the basis of the overvoltage responses to lightning random variables, a new statistical method for lightning insulation coordination is proposed and compared with other statistical methods. The statistical estimation of the risk of failure consists of (1) calculating the overvoltage responses to lightning random variables and (2) determining the failure zone of lightning stroke parameters and the probability. As an example, the overvoltage responses and probabilistic responses to lightning stroke parameters for a 330 kV substation are presented. Furthermore, a lightning tower proof against back flashover near the substation entrance is analyzed to obtain optimum protection.