BigPatents India

Two current differential relay devices 1 are, installed at each terminal 3 of a two-terminal powar transmission line 2, and connected to each other via two transmission paths 5 and 6, and perform current differential operations by transmitting and receiving the quantity data of electricity to each other. In the current differential relay device 1, two transmission means 14 normally each perform communications with the current differential relay device 1 of the other end of the power transmission line in parallel through the two transmission paths 5 and 6. Two current differential operation means 14 are connected to the two transmission means 14 respectively and perform independently two-series of current differential operations independently for each series associated with each of the transmission paths 5 and 6. The signal generation means 20 obtains the logical disjunction of the two-series of current differential operation results by means of the logical disjunction means 21. and uses the logical disjunction to generate a trip signal by means of the sequence operation means 15. The present invention provides a highly reliable current differential relay device of a high operating ratio which is capable of continuing the power transmission line protection function without any discontinuation even when one of the duplexed transmission paths has a transmission defect, as well as providing a signal processing method for the current differential relay device and a power transmission line protection system. No. of Pages : 40 No. of Claims : 7