A Practical Assessment of the Power Grid Inertia Constant Using PMUs

TL;DR

This paper presents an improved method for estimating the power grid inertia constant using PMU data, focusing on frequency variation analysis to enhance system stability assessments.

Contribution

It introduces a novel approach to accurately estimate the grid inertia constant from PMU frequency data, including optimal interval determination for minimal error.

Findings

Effective estimation of the inertia constant for the Iranian power grid.

Demonstrated the method's accuracy in assessing system stability parameters.

Provided guidelines for selecting analysis intervals to reduce estimation errors.

Abstract

Installation of phasor measurement units (PMUs) in a number of substations in the power grid can help assess a set of its values and parameters, in particular those related to the dynamics when disturbances occur in the system. Inertia constant of the power grid is one of the system stability related parameters that is essential for planning of the system spinning reserve. Estimates of the grid inertia constant require precise information of the system frequency at the time of disturbance. In this paper, an improved method for such estimate is presented, which is based on the derived data of frequency variations obtained from PMUs. In addition, a way to obtain the appropriate interval for the lowest error estimate is discussed. The method has been applied to assess the inertia constant of the Iranian power grid, by obtaining the rate of change of frequency after a disturbance in the defined interval, and the rate of specified power imbalance between electrical power input and output.