Limiting mechanism and equivalent analytical model of a bridge-type saturated core fault current limiter

Abstract

A saturated core fault current limiter (SCFCL) is a promising device to limit the fault current. Due to the nonlinear characteristics of the ferromagnetic materials and the AC to DC coupling effect, traditional equivalent models of SCFCL are not accurate. Moreover, the impact of the DC biasing magneto-motive force (MMF) attenuation on the limiting mechanism is lack of attention. Hence, this paper proposes an accurate limiting mechanism and an equivalent analytical model of a bridge-type SCFCL (BSFCL), considering the AC to DC coupling effect and the DC MMF attenuation. This paper presents the limiting mechanism of the BSFCL based on three working regions. Then an equivalent analytical model considering the coupling effect and the DC MMF attenuation characteristics is established. Finally, the limiting mechanism and an equivalent analytical model of BSFCL are validated by the analytical model method, electromagnetic simulation and experiments. The simulation and experimental results demonstrate the effectiveness and accuracy of the proposed method.