Investigation of the performance of a nove permanent magnet biased fault current limiter

With electric power consumption and distributed generations (DGs) keep growing, fault current levels are rapidly rising. Many approaches to limiting fault currents have been considered. Changing the grid topology or sequential tripping is costly, complex and may affect the stability of grid. On the other hand, uprating of circuit breakers and other equipment can be very expensive [1]. Fault current limiter (FCL) is one of the most effective and promising measures to limit excess current. With the development of permanent magnets, a number of permanent magnet biased fault current limiters (PFCLs) have been proposed for limiting fault current levels in the past [2]. Two main reasons for the available PFCLs mainly limited in the low voltage prototypes are: the finite flux density of permanent magnets as biasing sources and the risks of demagnetization and reverse saturation under large fault current. With this background, this digest proposes a new configuration of PFCL to enhance the biasing ability and the reliability in fault state, as well as decrease the impedance in the normal state.