A dual-functional bridge type FCL to restore PCC voltage

Abstract

The bridge type Fault Current Limiter (FCL) can limit the fault current without any delay and smooth the surge current waveform. Therefore the DC reactor and fault current increase and the voltage of Point of Common Coupling (PCC) decrease gradually. The voltage sag of PCC would affect the loads on the parallel feeders connected to PCC. In this paper, to limit the fault current and restore the PCC voltage, the power quality improving function is proposed and integrated in the bridge type FCL. This function is realized by a resistor and parallel switch which are in series with DC reactor. It is shown that controlling turn on and turn off duration of switch, can not only limit the fault current but also restore the voltage of PCC during fault. The theory of proposed bridge type FCL for limiting the fault current and improving the power quality has been presented and its model has been simulated by PSCAD/EMTDC software. A test setup has been built and the measurement results have been compared with the simulation results. It is shown that the proposed FCL is superior over the conventional bridge type FCL.