A Tunable-Inductor-Based Fault Current Limiter

With the expansion of distribution power system and renewable energy, it has become a challenging task to limit fault current effectively and economically in the complex power systems. Fault current limiter (FCL) provides a solution to the challenge. This article presents a new tunable-inductor FCL (TIFCL), which consists of a voltage-controlled tunable inductor, a driver circuit used to supply an external control voltage to the magnetic core of the tunable inductor, and a controller. When a short-circuit fault occurs, the TIFCL can be controlled to boost its inductance to the maximum value immediately to suppress the fault current. This is achieved by altering the external control voltage applied on the tunable inductor through the driver circuit. The configuration, characteristics, working principle, component sizing consideration, driver circuit, control and operation, and energy loss analysis of the TIFCL are elaborated in the context of a DC power system. The TIFCL concept is first validated by simulation in MATLAB/ Simulink. Then, a laboratory prototype of the TIFCL is designed, constructed, and tested in a DC power system to further prove the concept. The prototype test results demonstrate that the TIFCL can respond immediately to reduce the fault current through it by nearly 40%. The TIFCL provides a promising fault current limiting solution for the power system.