Power system frequency estimation using a least mean squares differentiator

The estimation of the power system frequency plays an important role in power quality assessment and power flow control. This paper presents a frequency estimator based on a moving average filter and on a least mean squares differentiator applied to the phase-angles of the grid voltages. The phase-angles are obtained using the Clarke transformation. The estimator achieves a high rejection to the grid disturbances such as unbalances and harmonics. A recursive version is proposed allowing an efficient computational implementation. The estimator performance is validated and compared with four other estimators by several simulations.