Solid-State Fault Current Limiter based on Magnetic Turn off Principle

Abstract

In this paper, a new type of Solid-State Fault Current Limiter(FCL) is proposed. Magnetic Turn off(MTO) FCL is composed of transformer cores and windings. And it utilizes thyristor controller to implement limiting operation. The primary winding is connected to the power grid. The secondary & tertiary windings are wound opposite direction to the primary winding. During the 'Turn On' state, magnetic fluxes produced in the primary winding are canceled out by the secondary winding. The secondary & tertiary windings are controlled by thyristors, and this state makes no impedance throughout the FCL. When fault occurs, MTO FCL will be immediately switched to 'Turn Off' state and this makes the secondary & tertiary windings open. After this operation high impedance will be induced throughout the FCL. MTO FCL is expected to be more practical to implement, because it does not use any superconducting materials or additional complex cooling systems.