Reliability enhancement of an interconnected power system using fault current limiter

Renewable energy technologies are growing day by day. Whenever a new DG unit is connected to the main grid or in case of occurrence of fault there will be considerable increase in the magnitude of current in the line. Different kinds of symmetrical (LLL) and unsymmetrical (LG, LLG) faults can occur in power system, out of which the three phase short circuit fault will be the most severe one and this can result in sudden increase of current to a very high value, which exceeds the maximum rating of the protective devices used. In this paper a resistive fault current limiter is used for limiting the three phase short circuit current. Simulations are carried out to demonstrate the effectiveness of the FCL. Introduction of FCL can considerably affect the overall reliability of the system. FCL reduces the magnitude of short circuit current through the protective devices. Here the reliability of the system is analyzed in a test bed with and without FCL and the changes in the reliability indices are studied. Simulation results show that with the incorporation of FCL, the overall reliability of the system gets improved.