Independent Control of Multi-Terminal Voltage Source Converter Based HVDC Link Analyzing for DC Faults

Abstract

The ability to control the active power, reactive power, AC voltage and DC voltage has provided the optimum utilisation of the power system.This paper presents the modeling of multi- terminal VSC based HVDC system. The reactive power by a particular terminal can be maintained constant or controlled. The DC bus voltage and AC voltage is controlled by separate terminal, the active power flow is maintained by another terminal. Each terminal can control up to 2 parameters depending on the requirement. Each controlled parameter requires tuning of PI controller gains in order to achieve satisfactory performance. The analysis of Voltage Source Converter based High Voltage Direct Current is carried out using vector control. The multi terminal response of a VSC-HVDC system during load changes, power reversal and line to ground fault on DC cable are analyzed. Simulation is carried out in RSCAD/RTDS software and the performance of the system is presented.