Monitoring of power system dynamics under incomplete PMU observability condition

Abstract

This work presents a hybrid state estimation procedure that allows power system dynamics associated to slow and fast transient events to be accurately monitored considering a limited amount of phasor measurement units. The proposal represents an enhanced version of a previously developed static state estimation approach. This time, two main changes are introduced. First, a weighted least absolute value estimator instead the conventional weighted least square technique is used to estimate bus voltages in transient regime. This makes the estimation process more robust at fast scan rates. Second, an extended Kalman filter based dynamic state estimator is integrated. Thus, the proposed scheme is able to estimate, along with static variables, dynamic variables of all generators and motors in the power system regardless of the availability of phasor measurement unit measurements at terminal buses. This is possible thanks to a novel data-mining based methodology for full phasor measurement unit observability restoration. Performance parameters such as accuracy, computing time and convergence properties are assessed by applying the estimation procedure to the New England benchmark system under different operating conditions.