Performance analysis on various controllers of VSC — HVDC transmission systems

Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) technology is a very attractive power transmission technology. The VSC based HVDC transmission uses IGBT (Insulated Gate Bipolar Transistors) switches having turn-on and turn-off capability and having special characteristics compared to Current Source Converter (CSC) based conventional HVDC technology. Among various control methodologies used for VSC based HVDC, vector control, nonlinear control and independent P-Q controller based on analytic expressions have been developed and analyzed in this work for sending end control station 1. Similarly, in the receiving end station 2, DC and AC voltage controllers are realized with traditional PI controllers have been analyzed. The performance of the proposed controller has been investigated under different operating conditions including post fault recovery. The effectiveness of the proposed various controllers are demonstrated through digital simulation studies on VSC-HVDC transmission system, using PSCAD/EMTDC software package under short time Line-Ground fault in both AC systems in two terminal VSC - HVDC systems.