Grid Inertia Support Enabled by Smart Loads

The increasing penetration of renewable energy resources (RESs) leads to a continuous displacement of synchronous generators. Since the grid integration of RESs is usually achieved through inertialess power converters, the system inertia reduces and the power system frequency stability is compromised. Consequently, unexpected generator tripping, load shedding, and even blackouts may occur and pose a great threat to the system normal operation. In view of these challenges, this article explores the possibility of providing the inertia support from power-electronics interfaced smart loads. Specifically, a transformerless electric spring topology and the associated control strategy have been developed to provide a substantial inertia support from the noncritical load. As compared with existing inertia enhancement techniques, the proposed solution is cost-effective without the need of additional energy storage units. The smart load inertia provision capability is quantitatively analyzed and experimentally verified on a laboratory-scale test. In the testing results, 40% and 18% reductions of the rate of change of frequency and the maximum frequency deviation are, respectively, observed with a 12% smart load penetration ratio.