Comparison of fault current limitation with saturable reactor and dynamic voltage restorer

Abstract

Increased penetration of the distributed energy sources in the grid and the growth of complex electrical power networks can increase the short-circuit current level of the power system. This increased current level requires upgrading circuit breakers, switches, and other equipment, which can be expensive and cause high copper and switching losses. Fault current limiters are designed to address the impacts of high fault currents. This paper investigates a strategy to limit the fault current using a saturable reactor and dynamic voltage restorer. By employing the magnetic saturation of the core with DC bias control, the reactance inserted into the system is varied based on the fault. Fault current limitation through a saturable reactor is implemented and compared with a dynamic voltage restorer. The case studies are performed on 1) a radial system and 2) CIGRE-IEEE low-voltage system for both balanced and unbalanced fault conditions. For the radial system, fault current limited by saturable reactor has significantly less magnitude than the DVR, but for a complex system, there is only a small difference in line current magnitude. The simulation studies performed in the PSCAD/EMTDC simulation environment show that as a fault current limiter, the saturable reactor limits the fault current in less time than the DVR.