Analytical Nonlinear Reluctance Model of a Single-Phase Saturated Core Fault Current Limiter

A saturated core fault current limiter (FCL) is a device that is designed to limit the fault currents in electrical energy networks and consequently, protect existing network equipment from damage. Due to complex nonlinear magnetic properties, the performance of saturated core FCLs has largely been characterized through experimentation and finite-element analysis simulations. Although both of these techniques are quite accurate, they are time consuming and do not describe the behavior of FCLs in actual electrical networks. This has led to an increasing demand for an accurate analytical model that is suitable for transient network analyses. This paper presents the development of an analytical model of a single-phase open-core FCL, which accurately describes the nonlinear magnetic properties of the FCL through a reduced reluctance approach. The extension of this model to other saturated core FCL arrangements (such as closed core) is also discussed.