Paper Title
Implementation of a Resistive Superconducting Fault Current Limiter in a VSC-HVDC System

Abstract
The voltage source converter based high voltage direct current (VSC-HVDC) system and half-bridge modular multilevel converters are the most popular types of HVDC converters. VSC have many advantages as compared to traditional current source converters(CSC). One of the serious drawbacks of VSC is its vulnerable nature to DC side faults, since the freewheeling diodes act as a rectifier bridge and feed the DC faults. The severity of dc-side faults can be limited by connecting double thyristor switches across the semiconductor devices. By turning them on, the ac current contribution into the dc side is eliminated and the dc-link current will freely decayed to zero. The main disadvantages of this method are high dv/dt stresses across thyristors during normal conditions, and the absence of bypassing for the freewheeling diodes during dc faults since they are sharing the fault current with thyristors. This paper proposes Resistive type of superconducting fault current limiter(R-SFCL) to limit the amplitude of fault current of VSC-HVDC system. The SFCL exhibits superconducting state during normal condition and offers resistive state under fault condition. MATLAB simulationsare carried out to study the effectiveness of the proposed model. Keywords - Superconducting Fault Current Limiter(SFCL), VSC-HVDC System, Fault Limiting, Fault Analysis.