Applicability of nonlinear reluctance model to a closed core Fault Current Limiter

A saturated core Fault Current Limiter (FCL) is a fault current reducing device that has attracted significant attention from both researchers and electricity utilities. The behaviour of saturated core FCLs has so far been characterised largely through experimentation and/or Finite Element Analysis (FEA) simulations, primarily due to the intricate nonlinear magnetic characteristics of the device. Both these techniques, while accurate, fail to demonstrate the behaviour of FCLs in actual electrical networks. Hence there is an increasing need for an accurate model of the FCL that can be easily incorporated into transient network analysers. This paper presents the development and applicability of an analytical model of a single-phase FCL with a closed core topology, which accurately describes the nonlinear magnetic properties of the FCL through a reduced reluctance approach. The model is implemented in an electromagnetic transient network simulation package and the simulation results are validated against experimentally measured data.