SETT OCH ANORDNING FOR FELRIKTNINGSDETEKTERING I ETT ELEKTRISKT FLERFASNET

摘要

The detection of the direction of a fault on an electrical transmission line in the case of faults close to the measuring station is problematical because of the low measuring voltage, particularly for bipolar short-circuits, with which the measuring voltage UK appears as the difference between the phase voltages U'S, U'T which have a small difference in phase angle. Measuring errors and deviations in the measuring channels can then lead to extensive errors in the decision regarding direction. The invention solves this problem by introducing an additional phase angle alpha into the phase position of at least one of the phase voltages U''T used for the formation of the fault measuring voltage UK.