VSC-MTDC Operation Adjustments for Damping Inter-Area Oscillations

Application of voltage source converter based multi-terminal high-voltage direct current (VSC-MTDC) grids operation adjustment for damping inter-area oscillations are addressed and analyzed in this paper. The new operation adjustment method is proposed to meet short-term solution requirements and accommodate critical operation conditions where the conventional damping stabilizer by using active power modulation cannot provide sufficient damping. Based on the sensitivities with respect to the active power injections of VSCs and the interior point algorithm, an operation optimization method is presented to obtain a proper VSC-MTDC operation scheme to achieve better damping performance for an ac/VSC-MTDC system. For some critical operation conditions in which an inter-area oscillation has been detected, an operation rescheduling method is proposed as an emergency oscillation control. Time-domain simulations are performed on a New England system with a five-terminal MTDC grid. A comparative study with a conventional damping stabilizer is also included in the case study. Both the theoretical analysis and the time-domain simulations have verified the effectiveness and superiority of the two proposed methods.