Improved "Augmented MVDR Spectrum-Based Frequency Estimation Algorithm" for Unbalanced Power Systems

This article proposes an improved augmented iterative minimum variance distortionless response (AI-MVDR) frequency estimation algorithm which resolves a significant performance degradation of the AI-MVDR algorithm at off-nominal frequency of unbalanced power signals. This problem of the AI-MVDR algorithm is caused by the omitted terms in computing the augmented covariance matrix which is suggested to compensate the unbalance effect. In this article, a new frequency estimator is analytically derived considering the effect of the omitted terms by replacing a fixed nominal frequency parameter with a variable frequency parameter in obtaining the augmented covariance matrix. The performance of the derived equation is also verified through computer simulations.