Solid State Fault Current Limiter (SSFCL) in Power System – A Case Study

Abstract

Increasing generation to meet the load growth and interconnections between systems to improve reliability and power transfer capability are likely to increase the fault current levels. If the resultant short circuit current exceeds the existing equipment rating, they must either be upgraded or replaced or reconfigure its system to reduce the new available fault current. Both of which are very costly or time escalated process. Hence it is preferred to explore the feasibility of utilization of existing equipment with current limiting devices. Current limiting using passive element like series inductor reduces system stability and load flow. To overcome this problem, the series reactor is made to come into services only for the duration of fault. This paper proposes new methods for fast acting current limiting using Solid State Fault Current Limiters (SSFCL) that employs power electronic switches to overcome the limitation of the passive current limiters. Modeling and simulations of these methods are performed on a typical 400 kV power system using PSCAD/EMTDC. The results of which confirm that the fault level can be effectively reduced.