A Unified AC-MTDC Power-Flow Algorithm with IDCPFC

A unified power-flow algorithm of AC power systems integrated with multi-terminal high-voltage direct current (MTDC) grids incorporating the interline DC power-flow controller (IDCPFC) is presented in this paper. The MTDC grids are based on voltage-sourced converter (VSC) technology. Pulse-width modulation control is employed for the VSCs. As against most of the research works published in this area, in this algorithm, the VSC modulation indices are considered as unknowns. The IDCPFC considered for the power-flow management of the DC grid is a generalized one, with an arbitrary number of DC voltage sources. In the proposed model converter losses are also included. All case studies are carried out in MTDC grids embedded in the IEEE-300 bus test system. For all the case studies, the power-flow algorithms were implemented with MATLAB. In all occurrences, a mismatch error tolerance of 10(-10) p.u. was selected. Results obtained with case studies on AC-MTDC systems validate the proposed work.