An Adaptive Voltage Droop Control mechanism for Multi-Terminal VSC-HVDC System for Offshore Wind Farms

摘要

In practical power system, power balance is achieved by making input power equal to the power output plus losses. In HVDC system, dc voltage control is the indicator of power balance. A balanced dc link voltage is a guarantee of balanced power transfer among the terminals of multi-terminal HVDC (MTDC) system. In MTDC system, droop control is employed to regulate the dc link voltage by adjusting the Voltage Source Converter (VSC)'s current to have balanced active power. Voltage droop control method allows a communication-free load sharing between converters. This paper presents the improved direct voltage control technique to ensure maximum power transmission in MTDC system. MTDC grids increase the stability during both dynamic and steady-state to integrate offshore wind farms to onshore networks. Simulation of MTDC system based on one offshore and two onshore platforms has been developed in PSCAD/EMTDC and results have been analyzed for the reliable operation of the system.