A New Type of Fast-Response Fault Current Limiter Topology for HVDC Application

Abstract

The inductance of a permanent magnet-biased saturated fault current limiter (PMFCL) increases automatically with the fault current. It can quickly restrain the rising speed of direct current (dc) fault current. However, when the dc circuit breaker (DCCB) opens, the PMFCL will delay the current drop speed and generate overvoltage, which will increase the voltage stress on the DCCB. In this article, a new type of fast-response FCL (NFCL) is proposed. It has the advantage of improving the fault current drop speed. Besides, it can reduce DCCB overvoltage, thus protecting the expensive insulated gate bipolar transistors in the DCCB. In addition, it greatly reduces the energy absorption in the DCCB, thus reducing its manufacturing cost. The NFCL operates automatically without a control device, which means that it responds faster. Moreover, the diode is on the low-voltage side, meaning that insulation manufacturing cost can be reduced. First, the working principle of NFCL cooperation with the DCCB is introduced. Then, the main electromagnetic parameter design requirements of the NFCL are analyzed. Their feasibility is verified by electromagnetic circuit simulation, and a prototype is built and tested. Finally, the experimental and simulation results show that NFCL can improve current drop speed effectively.