A Coordinated Voltage Control Method for Suppressing Currents Induced by Closing-Loop Operation in Offshore Wind Power Systems

Offshore wind power systems can achieve both the maintenance requirements and the better utilization of wind resources without turbine disconnection by closing-loop operation. While the closing-loop operation may cause large loop current because of the voltage differences at the closing-loop point. To address that closing-loop challenges in offshore wind power systems, the loop current characteristics are analyzed firstly. Then a coordinated voltage control method consisting of the voltage phase difference control and the voltage amplitude difference control is proposed, where the former is realized by coordinating with the wind power converter (WPC) and the latter is achieved by coordinating with the static var generator (SVG). By adjusting the active power of each WPC and the reactive power of each SVG, the voltage phase difference and voltage amplitude difference at the closing-loop point are attenuated, thus suppressing the large loop current. Finally, the effectiveness of the proposed coordinated voltage control is verified by simulations.