Novel Topology of DC Energy-Released Circuit For Saturated-Core Fault Current Limiter

The saturated-core fault current limiter (SCFCL) has been studied by several scholars in the past decades. However, these studies have mainly focused on the AC coils of the SCFCL, the DC excitation has seldom been mentioned. In this paper, the DC coil of SCFCL is studied as well as the influence of the novel structure of tightly-coupled SCFCL (TSCFCL) on the voltage of DC coil. A novel DC energy-released circuit is proposed, which overcomes the shortcoming of traditional single topology whose energy-released speed is limited by withstanding voltage of IGBT. In order to select a suitable structure of air gap for fault current limiter, the effects of different structures on the saturation of the core are studied. A novel simulation method is presented in this paper which can overcome the drawback of traditional finite element analysis cannot simulate the switching characteristics of IGBT under high frequency. Finally, a prototype is manufactured to verify the theory of this paper.