Fast clearing and protection of Power Systems with Fault Current Limiters and PLL-Aided Fault Detection

Abstract

In this paper, a new method is proposed that can be used to discriminate faults from switching transients. The method is primarily intended for use in systems where fast fault detection and fast fault clearing before the first peak of the fault current are required. An industrial system, in which high short-circuit power is desired but in which high short-circuit currents cannot be toleratedis an example of such a system. A phase-locked loop (PLL) is used to perform the discrimination. Computer simulations have been performed and it has been demonstrated that the output ofthe PLL is completely different for a fault compared to a switching transient. This difference can be used for discrimination between fault and a switching transient.