Application of SMES Unit in Improving the Performance of an AC/DC Power System

This paper investigates the use of a superconducting magnetic energy storage (SMES) unit to improve the performance of an ac/dc power system. In this context, investigations have been conducted on a large turbine-generator unit connected to a high-voltage direct current (HVDC) system. The impact of HVDC converter station faults on the torsional torques induced in turbine-generator shafts with and without using an SMES unit is elaborated. Faults considered are fire-through, misfire, short circuit across the inverter station, flashover, and a three-phase short circuit in the ac system. These investigations are studied using an electromagnetic transient program power system simulation/electromagnetic transients including DC (PSCAD/EMTDC) and the results are presented in the form of typical time responses as well as harmonic analysis.