In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include the DC voltage droop control. In the VSC based MTDC grids, the DC droop control is regarded as more advantageous in terms of the operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently.
- Multi-Terminal High Voltage Direct Current (MTDC) grid
- Voltage Source Converter (VSC)
- AC/DC combined power flow analysis
- DC droop control