A generic Inertia Emulation Controller for multi-terminal VSC-HVDC systems

A generic Inertia Emulation Controller (INEC) for Multi-Terminal Voltage-source-converter based HVDC (VSC-MTDC) is proposed in this paper. The proposed INEC can be incorporated in any grid-side-voltage-source-converter (GVSC) station, allowing the MTDC terminal to contribute an inertial response during system disturbances, in a similar fashion with a synchronous generator. The DC link capacitors of MTDC are utilized by INEC to exchange the stored energy with the AC grid by varying the overall DC voltage level of the MTDC network. The derivation process of the INEC algorithm and its implementation to the conventional VSC control system are presented, and the impact of total DC capacitance of the MTDC network on DC voltage variations is discussed. The proposed INEC for MTDC systems are validated by Matlab/Simulink under demand changes in a simulated multi-machine power system with a MTDC transmission system, and the effectiveness of damping postfault oscillations is also investigated.