Fast estimation of power system frequency using adaptive internal-model control technique

This paper presents a new approach to the fast estimation of power system frequency. The approach is adopted from the application of internal model based periodic disturbance cancellation technique in the control field. Frequency can be estimated by feeding the power system signals into a control system with an internal model incorporated in the feedback loop. After the first about 20 ms convergence, the approach is able to provide accurate noise-free estimates in less than 10 ms despite the presence of harmonics and DC decay. The estimation performance has been improved by 50 percent by introducing a notch filter to the adaptation loop. Computation requirements for the proposed method are very low compared to existing methods. The design of the control system is also described in the paper. Simulations are conducted using computer synthesized signals.