Effects of Modified Inertia Constant and Damping Coefficient on Power System Frequency Response

Abstract

The configuration of modern power system is drastically changing due to integration of distributed energy resources (DER) and responsive loads. Despite their advantages in terms of eco-friendliness and reliability enhancement, DER and responsive loads pose several challenges to the grid’s operation and stability. Amongst these challenges are the modification in two critical system parameters: inertia constant ( H ) and damping coefficient ( D ). Typically, these parameters are considered unchanged during the operation of a power system. However, the high penetration of responsive loads and BESS may alter their values from the calculated or presumed values. In this work, an analysis of power system frequency response is presented considering the modifications in these two parameters. After explaining how DER and responsive loads modify these parameters, it is demonstrated that a mismatch between actual and presumed values of these parameters may degrade the reliability and economy of the power system. The study considers two typical configurations (i.e., with and without automatic generation control) of the power system, and highlights the importance of accurate calculation of H and D when DER and responsive loads have significant shares.