System Control Strategies for Renewable Energy-Integrating Grids via Voltage Source Converter-Based High-Voltage Direct Current Technology

Abstract

The worldwide promotion of carbon-neutral policies is leading to a continuously growing percentage of electricity being derived from renewable energy, which makes it feasible to design power systems composed of 100% renewable energy in the future. The question of how to realize stable transmission for 100% renewable energy-integrating grids under different operating conditions needs to receive more attention. Voltage source converter-based high-voltage direct current (VSC-HVDC) technology is one of the prospective solutions for large-scale renewable energy integration due to its unique dominance in areas such as independent reactivity and active control. In this study, we design a novel, 100% renewable energy system through grid integration via a VSC-HVDC system structure and a control strategy. Unlike in other research, a mixed control strategy based on grid-forming control (PSL) and grid-following control (GFL) is developed to realize smooth switching in order to ensure secure transmission and consistent operation when the operating conditions of the 100% renewable energy-integrating grid changes. The simulation results indicate that the proposed system structure and control could stabilize renewable energy transmission under normal operation conditions and provide necessary grid support under different system disturbances.