Location-Dependent Impacts of Resource Inertia on Power System Oscillations

Abstract

Inertial responses are seen by the system as the injection or withdrawal of electrical energy, corresponding to a change of frequency. The inertia of a machine primarily contributes to the power system transient stability. Oscillations are always present in the bulk power system due to the electromechanical nature of the grid. Poorly damped oscillations may cause system instability. Thus, this paper aims to study inertia's impacts on system primary frequency response, in particular on system oscillation modes. Both transient stability simulations and modal analysis are performed to provide insights into the extent to which inertia and its location influence the system oscillation behavior. Simulation results using both a small-scale test system and a large-scale synthetic network dynamic model are presented to verify the locational impacts of resource inertia.

Impact of Inertia Distribution on Power System Stability and Operation

“…It was also observed that when a large portion of the total power system inertia is concentrated at one machine, the mean of the local RoCoF is significantly larger compared to when the power system inertia is equally distributed across all machines. In [6][7][8] authors propose the effect of uneven inertia distribution on local RoCoF, system small signal stability and transient stability on the ERCOT power system. They claimed that inertia contributes more to local frequency stability than the global (system) stability.…”