Assessment of Nodal Inertia Estimation Methods for Future Power Systems: A Comparative Study

High penetration of unconventional generators such as renewable energy sources (RES) in the generation system requires special attention during disturbances to maintain grid stability and limit possible frequency deviations. New energy power system inertia because of the high penetration of RES has not only been reduced but also changed to be uncertain, time-variable, and has spatial characteristics. Therefore, power system effective inertia should be monitored for frequency stability control reasons and safe operation. This paper aims to quantify and assess the power system spatial-temporal inertia. Time-domain simulation method for nodal inertia estimation based on frequency divider formula (FDF) and swing equation is presented and compared to an analytical method from the literature. Robustness and efficiency of the proposed method is validated using IEEE 9 bus system. Sensitivity analysis as the: frequency measurement methods, ROCOF time window, effect of the size and location of the disturbance is performed to assets the factors that influence the simulation method. The results from the proposed simulation method are consistent with the analytical method in terms of evaluating system buses inertia ranking and recolonizing the area of high inertia and areas with low inertia.