Effect of Magnetic Saturation on the Current Limiting Characteristics of Transformer Type Superconducting Fault Current Limiter

Various types of fault current limiters have been proposed to reduce the fault currents in power transmission lines. The transformer type superconducting fault current limiter is one of the fault current limiters, and has many advantages such as design flexibility. By using an experimental fault current limiter, the short-circuit fault test was carried out for different fault phase angles. From the results of the experiments, it is confirmed that the transmission line fault current is seriously affected by the magnetic saturation of the transformer core. This has to be considered in the design of the transformer. Thus, in this paper, the transient characteristics of the transformer type super-conducting fault current limiter are analyzed by the numerical simulation considering the magnetic saturation of the transformer iron core and the time-dependent resistance of the current limiting device. The analysis is carried out by using the parameters obtained from the experimental superconducting fault current limiter. From the results of the analyses, the influence of the transformer core is clarified