Comparison of HVDC grid control strategies

The integration of renewable energy resources has increased possibility of application of multi terminal direct current (MTDC) system. In this paper, the primary level control of voltage source converter (VSC) and their design method is discussed. The control schemes for the MTDC system such as DC voltage control, voltage margin, droop control, coordinated and distributed DC voltage control are discussed and compared. A four terminal VSC based MTDC system is modeled in PSCAD. The performance of the controllers are compared under step load changes and fault on the DC grid.