Demand Side Contributions for System Inertia in the Gb Power System

As the penetration of intermittent, low carbon generation increases, system inertia will decrease dramatically and pose a major threat to system stability. The majority of research in this area investigates the methods of providing inertia from the supply side, but this paper develops a novel method that will evaluate the demand side contributions to system inertia based on historical data of frequency outage events in the GB power system. This is achieved by isolating the generation contribution from the total system inertia and considering the power/frequency ratio as an indicator of the additional inertia contribution from spinning reserve. The results show that the demand side could contribute an average of 1.75-s inertia constant in the system load base, representing 20% of the total system inertia in the GB power system. Finally, the system inertia distribution, the rate of change of frequency and the minimum primary frequency response requirements are investigated at a variety of demand levels.