Automated operation approach for embedded HVDC links during (N-1)-conditions in the AC system

In Germany, new HVDC links are planned for power transmission from the north to the south. One possibility is to schedule the operation of the HVDC links, which are to be embedded in the AC grid. Because the calculation via optimal power flow is time intensive and does not include the current grid situation, a simplified control method is introduced. It has the advantage that the HVDC power set point can be set automatically. Furthermore, another operation mode handles alert situations when an AC line loading is higher than intended and, therefore, adapts the power set point during (N-1)-conditions to avoid line overloadings. This paper proposes an automated method, which minimizes transmission losses while including the AC line loadings as limits for the HVDC power. A numerical case study shows the functionality of the proposed concepts and a detailed (N-1)-analysis investigates the behavior during unexpected line outages.