Farshad - Electric Power Research Center
Berahmandpour - Electric Power Research Center
Mehrabadi - Electric Power Research Center
Ranjbar - Electric Power Research Center

Increasing of fault current in transmission and distribution systems due to network expansion is one of the most important problems in power system planning and operation. It will be yield to use of circuit breakers with higher capacity of interruption. While the other destructive effects of this high fault current is still unsolved. One of the best solution for this problem is obtained by the usage of Fault Current Limiters (FCL). Althogh the benefits of FCL is cleared in the previous works, the main criterion which will prove the usage of FCL is economical concept. In this paper with extending the cost function in two case, without and with FCL and subtracting these functions, the net benefit of usage of FCL is determined. By optimization of this function with respect to the size of FCL components for the buses with higher priority, the optimal location and size of FCL are obtained. Based on this algorithm, a computerised software is developed. This software is executed for Iran 230 kv and 400 kv transmission networks. In this way the two most important buses and two lines.for FCL installation are suggested.