A Paper of Determination of Controlling Characteristics of the Monopolar HVDC System

Due to cost effectiveness and less electrical fault hazards, the HVDC transmission is more suitable for long distance power transmission than that for the conventional AC transmission system. Moreover the utilization of power electronics has made HVDC technology competitive and reliable in comparison to HVAC system. The controlling mechanism of the DC link (either monopolar or bipolar) is the major concern for HVDC technology. Determination of control loop for system operation needs to commensurate with the conduction period of the semiconductor switching device. Generally IGBT and MOSFET are widely used as switching device whose delay angle, advance angle and extinction angle need to be matched with the controlling mechanism of the converter and inverter section. In this paper, the controlling characteristics of a monopolar HVDC system are determined by using MATLAB/Simulink. The Simpower tool box is used for designing the controlling blocks of the HVDC system. The controlling characteristics of the monopolar HVDC system can be determined from the simulation results of the gate currents of IGBT, output voltages of converter and inverter and modulation index.