Influência da suportabilidade dielétrica de disjuntores em manobras controladas de linhas de transmissão.

Abstract

In the present work, we have investigated, via electromagnetic transients simulations, the effect of prestrike on the performance of a controlled switching technique applied to transmission line closing operations, energization and reclosing. An increase in transient overvoltage is verified whenever prestrike is applied to the circuit breaker model. Such result is natural, since the occurrence of a prestrike may cause the electric circuit to close before the effective closing of the breaker contacts. In addition to making digital simulations more realistic, the inclusion of a prestrike model enables the investigation of techniques that aim at minimizing the effect of such breaker behaviour in controlled switching. Two models of breakers were used in the present study. The first model, whose supportability characteristic is represented by a straight line with a slope equal to the rate of decrease of dielectric strength (RDDS), is the most suitable for such studies due to its simplicity. The second model includes an electric arc equation used which, besides rendering the breaker’s representation more accurate, it exhibits greater complexity: it requires the parameters of the electric arc equation and a more demanding model’s simulation.