Adaptive Adjustment of Noise Covariance in Kalman Filter for Dynamic State Estimation
For power system engineers, this work improves dynamic state estimation accuracy, but it is an incremental improvement over existing adaptive filtering techniques.
The paper proposes an adaptive method to estimate noise covariance matrices Q and R in Kalman filters for dynamic state estimation of synchronous machines, showing improved robustness against initial errors in Q and R compared to conventional methods in simulations on a two-area model.
Accurate estimation of the dynamic states of a synchronous machine (e.g., rotor s angle and speed) is essential in monitoring and controlling transient stability of a power system. It is well known that the covariance matrixes of process noise (Q) and measurement noise (R) have a significant impact on the Kalman filter s performance in estimating dynamic states. The conventional ad-hoc approaches for estimating the covariance matrixes are not adequate in achieving the best filtering performance. To address this problem, this paper proposes an adaptive filtering approach to adaptively estimate Q and R based on innovation and residual to improve the dynamic state estimation accuracy of the extended Kalman filter (EKF). It is shown through the simulation on the two-area model that the proposed estimation method is more robust against the initial errors in Q and R than the conventional method in estimating the dynamic states of a synchronous machine.