Modeling and control of VSC-based high voltag direct current transmission system

Abstract

VSC-Based High Voltage Direct Current (VSC-HVDC) systems have the ability to control rapidly the transmitted active power and independently exchange reactive power with transmissions systems. The present work investigates the modeling and control of a high-voltage direct current (HVDC) transmission system based on three-level NPC converters. A feed-forward current control strategy using PI controllers has been performed in order to achieve a decoupled indirect active and reactive power control. By using this control strategy, not only the powers can be controlled independently but also the dynamic response time can be shortened. Furthermore, PI controllers are implemented for out loops control. In this work, Modeling and Simulation studies of a 3MW/±50kV back-to-back VSC-HVDC are presented. Different tests have been performed to confirm the satisfactory performance of the proposed system under active and reactive power variations and DC pole-to-pole Disturbances.