Enhancing Power Flow control in MT-HVDC system with Novel SST-based IDCPFC topology

Interline DC Power Flow Controllers (IDCPFC) plays a crucial role in Multiterminal-High Voltage Direct Current (MT-HVDC) systems for balancing the DC power flows in transmission lines. Conventional methodologies generally rely on single-stage topologies for IDCPFC, but their applicability to high voltage contexts is constrained by limitations in device ratings and susceptibility to electromagnetic interference (EMI). In interconnected networks with varying lengths of transmission lines, each line exhibits unique resistance levels, complicating the efficient achievement of voltage specifications. This paper presents to introduce a new high-voltage multi-terminal modular solid-state transformer (SST) based IDCPFC topology. The objective of this proposed topology is to expand the voltage range of IDCPFC to enhance power flow control within the MT-HVDC network. In order to minimize the switching losses of the proposed topology and validate its bidirectional feasibility, various modulation schemes are adopted. A thorough comparison of losses between conventional bidirectional topologies and the proposed topology is presented to demonstrate its effectiveness. The proposed control method is simulated on four cascaded modules based on case study of three nodes 500 MW system. The simulated results are further validated through experimental setup with two cascaded modules of 600 W.