A solid state fault current limiter control algorithm

The fault current limiter (FCL) is considered as the ideal solution to limit the fault current in integrated electrical power systems with distributed energy resources because of its speed of response. However, there are some practical application issues for FCL in commercial industrial deployments. In this paper, the coordination issue of FCL with the other protective devices is discussed making use of simulation and experimental results. The fundamental point of operating a FCL is that it introduces an additional equivalent impedance into the power system and thus influencing the operation of the other protective devices, sometimes, leading to malfunction. A formula is proposed in this paper to estimate the impedance range of the equivalent FCL in order to maintain the coordination with the other protective devices. An example is used to demonstrate that the fault current can be limited by controlling the switching position of a solid state fault current limiter (SSFCL) while maintaining system coordination.