Inertia emulation control of VSC-HVDC transmission system

The increasing penetration of power electronics interfaced renewable generation (e.g. offshore wind) has been leading to a reduction in conventional synchronous-machine based generation. Most converter-interfaced energy sources do not contribute to the overall power system inertia; and therefore cannot support the system during system transients and disturbances. It is therefore desirable that voltage-source-converter (VSC) based high voltage direct current (HVDC) interfaces, which play an important role in delivery of renewable power to AC systems, could contribute a virtual inertia and provide AC grid frequency support. In this paper, an inertia emulation control (IEC) system is proposed that allows VSC-HVDC system to perform an inertial response in a similar fashion to synchronous machines (SM), by exercising the electro-static energy stored in DC shunt capacitors of the HVDC system. The proposed IEC scheme has been implemented in simulations and its performance is evaluated using Matlab/Simulink.