Evaluation of the Performance of Using Interline Fault Current Limiter in High Voltage Substations in order to Reduce Short Circuit Current, Voltage Drop and Improve the Stability of Distribution Generation; Case Study: Substation in Special Economic Zone of AMIRABAD Port

Due to the expansion and development of the distribution networks and the use of distributed generators (DGs), the level of short-circuit current has increased significantly. Increasing the short circuit current level provides several challenges for network equipment. In this paper, the effects of using the inter-line fault current limiter (IFCL) to reduce the short-circuit current and improve the stability of DGs installed in the 230/63/20 kV AMIRABAD substation as a case study are investigated. It includes several output feeders for connecting loads and four DGs to a common coupling point 20 kV bus. In this substation, the connection of DGs to supply the power required by consumers, has increased the short-circuit current to a greater amount than the nominal capacity of the equipment. Also the occurrence of short-circuit in one of the feeders has led to voltage sag in the common bus and the instability of the generators. This has caused the exit of generators and sensitive loads connected to parallel feeders and finally reduce the reliability. IFCL consists of several rectifier bridge circuits and a common limiting resistor. It inserts the common limiting resistor in fault path for limiting the fault current level and consequently the voltage drop in the case of short circuit of the feeders. To prove the efficiency of the proposed structure for solving the problems of the studied network, the substation components in PSCAD / EMTDC software are simulated. The simulation results show that the proposed IFCL effectively reduces the fault current and voltage drop, as well as improves the stability of DGs.