EVALUATION OF UNCERTAINTIES IN DOUBLE LINE DISTANCE RELAYING - A GLOBAL SIGHT

Uncertainty sources, when relaying double lines with distance relays, during simple or intercircuit faults, are evaluated. Tendencies on err ors and their;magnitude are easily viewed in a forward reach settings vs. real fault distance covered plane. Contributions of different fact ors are separated and relations among them are established using the m entioned plane. Desired situations to be evaluated include any type of fault, for any previous state and any fault resistance, as well as an y type of distance unit. The intent of the analysis presented is not o nly to evaluate known tendencies of distance relay responses, in doubl e or single lines, but also to identify the causes and to show the use fulness of the employed methodology for any other type of study to be performed when calculating settings, analysing or designing the best p rotection philosophy in double or single lines.