Operation of series and shunt converters with 48-pulse series connected three-level NPC converter for UPFC

The 48-pulse series connected 3-level neutral point clamped (NPC) converter approach has been used in unified power flow controller (UPFC) application due to its near sinusoidal voltage quality. This paper investigates the control and operation of series and shunt converters with 48-pulse voltage source converters (VSC) for UPFC application. A novel controller for series converter is designed based on the ldquoangle controlldquo of the 48-pulse voltage source converter. The complete simulation model of shunt and series converters for UPFC application is implemented in Matlab/Simulink. The practical real and reactive power operation boundary of UPFC in a 3-bus power system is specifically investigated. The performance of UPFC connected to the 500-kV grid with the proposed controller is evaluated. The simulation results validate the proposed control scheme under both steady state and dynamic operating conditions.