Design and Transient Operation Assessment of Resonant FCLs in Bulk Power Systems

The increasing capacity of power systems and the continuing growth in interconnections within transmission networks to improve the reliability may cause the short-circuit fault current level of the equipment in the system, including the existing circuit breakers, to exceed their rated capacities. Therefore, the equipment must be either upgraded or replaced, which is costly and requires time-intensive procedures. Fault current-limiting techniques offer benefits to the system in such cases. Using passive elements, such as current-limiting reactors, is a well-known practice in power systems: however, they impact the power flow under normal operation, cause voltage drop, and might reduce the transient stability. Alternatively, resonant fault current limiters (RFCL) offer a dynamic solution based on proven technologies of current-limiting reactors and series capacitors. This paper presents a comprehensive framework to design RFCLs in bulk power systems. The presented approach uses a combination of mathematical analyses and numerical time-domain simulations to design the RFCL elements, and its effectiveness is assessed in test power systems.