Fast adaptive schemes for tracking voltage phasor and local frequency in power transmission and distribution systems

Devices specifically dedicated to highly accurate measurement of frequency have been described for specific applications like power system stabilizers. However, in most situations the digital estimate of the frequency deviation is needed concurrently with other decision quantities. Therefore, its value is usually obtained as a by-product of a more general-purpose algorithm, based, for instance, on the extended Kalman filtering or the recursive least error squares techniques. Unfortunately, a common problem with these Kalman filters is the high computational requirements, due to transcendental functions evaluation in real-time. Therefore, the need still exists for more clever implementations of the various real-time algorithms, which could alleviate the computational burden and enhance the adaptation speed during transients. To fulfil this need to some extent, two new methods suitable for fast adaptive estimation of voltage phasor and frequency deviation are outlined