Research on Dual-terminal Flexible HVDC Transmission System Based on Renewable Energy Access

Abstract

With the increasing demand for renewable energy and development of flexible direct current transmission technology (VSC-HVDC), VSC-HVDC system with renewable energy access has gradually became a research hotspot. Based on the above situations, this paper studies the topology and operation mechanism of a VSC-HVDC system with renewable energy access. For the choice of converter topology structure, this paper adopts the traditional two-level converter. For the control system, one end adjusts the DC voltage and reactive power, and the other end is used to regulate the active power and reactive power to meet the operation requirement. In order to further enrich the energy transmission path of dual-terminal VSC-HVDC system, a renewable energy system based on passive inverter is connected to the dc line. Furthermore, by introducing unipolar PWM modulation and designing line filter inductance, the three-terminal VSC-HVDC system based on renewable energy access will achieve ideal operation and flexible system control. Finally, the effectiveness is verified on MATLAB/Simulink simulation platform. The results show that the power received by the receiver is determined by the power emitted by the sender and the power received by the new energy branch when the receiver adopts constant DC voltage control.