Implementation of One and a Half Breaker Arrangement in Fierza 220 KV Substation with Prozanet Scada System

Fierza Substation has a one and a half circuit breaker arrangement. In Fierza Substation scheme, two busbars are connected through three circuit breakers. The name one and a half breaker coin the fact that each circuit has the “own†breaker and the middle breaker has to be used from both circuits. In normal operation when all elements are in working condition, all circuit breakers (C1, C2 and C3) are closed and both busbars are energized and share the load through each other. Any circuit failure will trip just the two circuit breakers adjacent to the fault, in order to isolate it. No other circuit breaker will have be affected from this fault. If a busbar short circuit happens only the breakers near to the busbar will trip and all the other circuits will proceed supplying power. In this arrangement it is also possible to take out of service both busbars, and still supply the transmission line directly through the middle circuit breaker (C2) from the generator directly. The last case is only possible if both circuit’s generator and supplied transmission line are in the same diameter. The philosophy of operation of such a scheme as a case study of Fierza Substation and the problems of operating this scheme from two different Authorities (KESH and OST) at the same time, is discussed in this paper. The implementation of this case is shown with Prozanet Scada system.