Online Inertia Constant and Thevenin Equivalent Estimation Using PMU Data

In this paper a new algorithm based on phasor measurements for estimating the Thevenin Equivalent (TE) and system inertia constant is proposed. The method estimates the network TE seen from a generator terminal and equivalent system inertia constant by means of phasor data that is available at Phasor Data Concentrator (PDC) center. It is shown that the parameters of the TE could be estimated at any system condition, but the value of system inertia constant is available only after some disturbances. The algorithm is tested on a standard Nine-Bus test system in different conditions. Results show that this method can efficiently estimate the TE both in steady-state and transient conditions as well as system inertia constant.