Power System Inertia Monitoring Using Recursive Weighted Least Square Algorithm Under Ambient Conditions

In this paper, we identify the transfer function model relating the active power to the bus frequency using recursive weighted least square (RWLS) algorithm with ambient signals measured by the phasor measurement units (PMUs). Then, the inertia at different hierarchies, i.e. individual generator, area and the whole system, are estimated from unit step responses of the identified models. Compared to the conventional methods using transient signals, the proposed method can estimate the power system inertia under normal operating conditions as well as provide the tracking trajectory of inertia in real-time. The effectiveness of the proposed method is validated in the IEEE 39-bus system.