Supervisory control of Bipole-based Multi-Terminal HVDC grids using Model Predictive Control including asymmetric operation

Multi-Terminal DC (MTDC) grids are gaining attention as potential architectures to interconnect multiple AC areas and renewable energy production sites. While symmetric monopole configurations are currently the most common, increased power flow and reliability needs are increasing the interest towards bipole configuration with ground return or Dedicated Metallic Return (DMR). This paper presents a supervisory control scheme based on Model Predictive Control (MPC) that smoothly steers the MTDC grid between operating points while ensuring compliance with various system limits. At the heart of the MPC lies a constrained optimization problem that determines a series of actions to be taken to best meet the power and average voltage references. Additionally, this paper demonstrates the capability of the controller to keep between limits the DMR current and neutral voltages following the outage of a single pole.