Performance Evaluation of Time Domain Transmission Line Models for a Statistical Study of Switching Overvoltages

The study of switching transient overvoltages in HV transmission lines is fundamental for insulation coordination purposes. It is well known that, in general, the poles of a 3-phase circuit breaker do not close at the same time, but in a sequential manner. An efficient way to take this into account for simulation purposes consists of performing several switching simulations with random closing times for each phase (and different for each event). This is known as Monte Carlo method. Evidently, the precision of this method is highly dependent on the software and transmission model applied for the study. In this work, the accuracy of several transmission line models included in two widely used transient simulation programs (ATP and PSCAD/EMTDC) is analyzed and compared in a statistical manner, by means of a Monte Carlo study of switching transients for two different tower configurations (horizontal and vertical disposition of conductors). For that purpose, a frequency domain method based on the numerical Laplace transform and the superposition principle is used as base solution.