Priority Control Strategy of VSC-MTDC System for Integrating Wind Power

Abstract

For the obvious advantages in integrating wind power, multiterminal HVDC transmission system (VSC-MTDC) is widely used. The priority control strategy is proposed in this paper considering the penetration rate of wind power for the AC grid. The strategy aims to solve the problems of power allocation and DC voltage control of the DC system. The main advantage of this strategy is that the demands for wind power of different areas can be satisfied and a power reference for the wind power trade can also be provided when wind farms transmit active power to several AC grids through the DC network. The objective is that power is well distributed according to the output power of wind farm with the demand of AC system and satisfactory control performance of DC voltage is obtained.

Review of the DC voltage coordinated control strategies for multi‐terminal VSC‐MVDC distribution network

“…However, attempts have been made by Haileselassie and Uhlen [38] to use the DC load flow analysis and converter loss estimation in determining the converter power and DC voltage references to enable precise power flow control. Other efforts to address the precise power flow issue resulted in new droop control variants proposed as ratio control in [64, 65] and priority control in [65, 66]. Fig.…”

“…This terminal controls the DC voltage by means of proportional–integral till its set limit by the system operator. When the converter terminal reaches its saturation, another converter with DC voltage droop (proportional) begins to receive or transmit the remaining power [31, 65, 66]. This control strategy is suitable in a small offshore MTDC network where a country wishing to have precedence can sell excess of its wind power capacities to neighbouring countries.…”