A combined directional and faulted phase selector element based onincremental quantities

摘要

In this paper, differential incremental or superimposed voltagenand current quantities are used in order to determine directionality ofna fault in a network. It is shown that this can be accomplished bynperforming three scalar products between three voltage and currentnphasor pairs. The relative levels of these same three scalar productsncan be furthermore used to identify the faulted phases. While, innultra-high-speed directional comparison relays, superimposed voltage andncurrent had to be treated in the time domain in order to get speed. Innthis paper, all computations are done in the frequency domain