Further development of HVDC control

The principal function of the HVDC control is to control the power flow between the terminals. Moreover, it has to stabilize fast the connected AC systems which can suffer from even small disturbances. The paper presents a new HVDC control concept which effectively copes with the disturbances particularly in weak systems. The studies performed by PSCAD/EMTDC use the CIGRE benchmark HVDC and back-to-back HVDC scheme to confirm the advantages of the new control concept compared to the conventional one. The studies show that the operating point does not return directly to the pre-disturbance operating point when the conventional control concept is applied, however, the direct movement can be observed when the new control is used. Moreover, the studies of the fixed capacitor (FC) and the fixed reactor (FR) switching in a back-to-back HVDC scheme show the new control is more effective in damping voltage oscillations compared to the conventional one.