Performance comparison of a permissive overreach transfer trip (POTT) scheme over IEC 61850 and hard-wire

The International Electrotechnical Commission (IEC) 61850 is a standard that allows communication integration of systems built from multivendor power protection relays. The standard describes the rules for integration of control, measurement, and protection functions within a power system network at the substation control levels. The standard was created with the idea of eliminating wiring in the substation and facilitating the communication between different relay vendors. This study implemented IEC 61850 standard in a Permissive Overreach Transfer Trip (POTT) scheme to protect a 166 mile, 230 kV transmission line using Generic Object Oriented Substation Events (GOOSE) messaging in the laboratory. Two multivendor digital line protection relays were placed at each end of the line to protect the transmission line via the POTT communication scheme. Faults were simulated at different points on the line using two modern relay test sets. A comparison of the POTT with IEC 61850 communication and a classic communication method, hard-wire, is made to determine the performance of the POTT with IEC 61850. It is observed that the maximum and minimum time delay between fault occurrence and the POTT operation with IEC 61850 communication is around 1.72 cycles (28.67 ms) and 1.50 cycles (25 ms), respectively, under laboratory conditions. The results on this research show that the POTT with IEC 61850 communication is faster or similar to the POTT with hard-wire communication