Synchronous switching of uncompensated transmission line, by considering the effect of coupling voltage between the phases, trapped charge and the characteristics of CB

Abstract

The synchronous closing technology is an effective way to reduce transient current and voltage, prevent equipment failures, and improve power quality. The proposed algorithm, first by considering the coupling voltages between phases and the residual voltages in an uncompensated transmission line, calculates the zero instant of the voltage curves (ZVC instant) across the poles of the circuit breaker (CB) that is ideally the optimum instant to close the CB. Although other studies have utilized ZVC detection by solely considering either coupling or residual voltages. Secondly, the algorithm seeks to account for the mechanical scattering time of the CB and the rate of decrease of dielectric strength (RDDS) by incorporating delay times into the previously calculated delay values. Although other works have investigated the effect of RDDS or mechanical scattering operation time on synchronous switching to some extent, they have not fulfilled any optimization taking both of them into account.By exerting this algorithm, each phase of CB is closed in the ideal optimum closing target (ZVC instant) with a maximum error of one sample, and then, taking into account the CB characteristics, by compensating the RDDS and mechanical scattering time, CB is energized in the optimal time interval, where pre-strike voltages are minimized.