An Economical Three-Phase Fault Current Limiter Considering Different Types of Fault

Abstract

With the rapid development of the power system, the fault current becomes a big problem. The current limiting measures become more and more important. The saturated-core fault current limiter(SFCL) is one of the promising methods [1]. The most serious fault in electric power system is three-phase short-circuit fault, and the fault current is more likely to exceed the circuit breaker's capacity. The use of three single-phase current limiters at the same time will need a lot of ferromagnetic material and space. A compact three-phase SFCL was proposed in [2], but it cannot limit three-phase fault current [2]. So we propose a novel structure of Economical Three-phase Saturated-core Fault Current limiter(ETSFCL). The novel structure has good clipping performance at three-phase fault conditions. Compared to three single-phase SFCLs proposed in [3], it saves a lot of ferromagnetic material and reduces the AC flux through the permanent magnet. The stability of the permanent magnet is greatly improved and the risk of demagnetization is reduced. In this paper, the operating principle of the proposed structure is explained by analyzing its equivalent magnetic circuit and electrical circuit. FEA models were established in ANSOFT to verify the its effectiveness.