Optimal Allocation of Multi-Terminal DC Systems in High Penetration Renewable Energy Power Grids

This paper proposes a method for determining the optimal locations and capacity of multi-terminal DC (MTDC) systems in power grids with high renewable energy penetration. Using a master-slave structure for MTDC, DC voltage and power control are modeled. A multi-objective optimization problem is addressed using a voltage deviation profile index (VDPI), line power loss index (LPLI), and capacity penalty index (CPI). The optimization is solved through the artificial bee colony (ABC) algorithm. The method was validated in the IEEE-30 bus test grid. The results showed that an 18 MW MTDC system was optimal, with the DC voltage control converter at bus 30 and power control converters at buses 11 and 26. After MTDC integration, VDPI improved by 26.7%, and LPLI decreased by 19.0%. Additionally, the minimum voltage increased from 0.983 p.u. to 0.997 p.u. This highlights the impact that the locations and capacity of MTDC have on grid stability and efficiency.