Accurate Parameter Estimation for Unbalanced Three-Phase System

Abstract EN

Smart grid is an intelligent power generation and control console in modern electricity networks, where the unbalanced three-phase power system is the commonly used model.

Here, parameter estimation for this system is addressed.

After converting the three-phase waveforms into a pair of orthogonal signals via the α β-transformation, the nonlinear least squares (NLS) estimator is developed for accurately finding the frequency, phase, and voltage parameters.

The estimator is realized by the Newton-Raphson scheme, whose global convergence is studied in this paper.

Computer simulations show that the mean square error performance of NLS method can attain the Cramér-Rao lower bound.

Moreover, our proposal provides more accurate frequency estimation when compared with the complex least mean square (CLMS) and augmented CLMS.