Power system virtual inertia implemented by grid-connected solar photovoltaic inverters

Abstract

Solar photovoltaic (PV) generation systems are increasingly deployed in modern power systems. However, in comparison with conventional power generation, as the capacity of PV generation systems increases, the inertia of power system will be reduced. In this way, system frequency deviations would surpass the permissible scope under frequency contingencies, leading to undesirable consequences. This is considered to be one of the major scientific challenges faced by those countries which have committed to raising the share of renewable generation.

To address this problem, a method of emulating the inertia by the energy stored in a capacitor is proposed in this paper. Such capacitor is contained in a grid-connected power converter. Without modifying the original inertia coefficient in the system, the capacitance of capacitors and dc-link voltages can be changed to control the virtual inertia.

Moreover, simulations can show that this proposed method is useful in regulating frequency deviation.