Load Modelling Effects on Power System Inertia Response

Abstract

As countries around the world begin to increase the contribution of renewable energy generation into their interconnected power systems, a large portion of this generation is interfaced to the power system through power electronic converters. As the increase in their contribution begins to displace traditional synchronous generation through end of life and/or early decommissioning, the power system inertia will decrease. This increases the rate of change of frequency (ROCOF) making the frequency of the system respond quicker to power imbalances. In this paper, load modelling and their effects on ROCOF are explored to highlight the key considerations when deriving conclusions based on the power system inertia outlook. The outcome showed that more realistic composite load structures based on type of loads that reflect the corresponding economic activity will present different outlooks on the inertia response of the power system. The outcome of this research also demonstrates how composite load modelling effects on the network and interlinked transmission line loading can result in lower frequency nadir and ROCOF. This outcome is very critical in understanding the dynamic loading conditions on transmission lines against possible contingencies and the network inertia status.