A Hybrid Current Source Converter-Based HVDC System with Power Coordination Control for Enhanced Reactive Power Support

HVDC technologies based on fully controlled devices offer numerous technical advantages, such as flexible active and reactive power control and black-start capability, making them highly promising for large-scale renewable energy integration and long-distance power transmission. However, their widespread adoption is constrained by high costs and significant power losses. Unlike existing hybrid HVDC schemes predominantly based on LCC-MMC structures, this paper proposes a novel hybrid current source converter-based HVDC (HCSC-HVDC) topology composed of IGCTs and thyristors, which enables power decoupling and achieves an approximate 70.5% reduction in high-voltage capacitor requirements, fundamentally improving system economy and structural efficiency. Firstly, the topological structure of the HCSC is introduced and a mathematical model is established. Then, the power operating range of the hybrid converter is quantitatively analyzed, and an optimization method for AC filter parameters is derived, based on which a power decoupling control strategy and a reactive power coordination control (RPCC) strategy are proposed. Finally, PSCAD electromagnetic transient simulations verify the effectiveness and feasibility of the proposed topology and control methods.