Enhanced Frequency Support of MMC-MTDC Systems with Offshore Wind Plants Integration

다국어 초록 (Multilingual Abstract)

With the increasing penetration of renewable energy generation in the power grid, there have been several actual cases of high-voltage direct-current (HVDC) systems replacing conventional high-voltage AC power transmission systems for long-distance power transmission. The widely used full-scale converter (FSC) wind turbines (type 4), unlike the traditional synchronous generators, cannot provide inertial constant support for system frequency stability owing to their special structural problem. Therefore, a control strategy that provides virtual inertia for a system using an HVDC inverter is proposed. Currently, this method is mostly used in a single HVDC transmission line. This study investigates the frequency stability of a modular multilevel converter-based multi-terminal HVDC combined with offshore wind power plants. An enhanced virtual inertia compensation strategy is proposed to improve the frequency stability of onshore AC systems. This study uses the multi-terminal HVDC network of the CIGRE benchmark to build a power grid model and simulate AC systems with different levels of robustness. The simulation results prove the effectiveness of the reinforcement method.