DIRECT ESTIMATION OF VOLTAGE PHASOR, FREQUENCY AND ITS RATE OF CHANGEUSING NEWTON ITERATIVE METHOD

A new approach to the design of a digital algorithm for direct estimat ion of voltage phasor, frequency and its rate of change is presented. The algorithm derived is based on Newton's iterative method, very comm only used in the field of unconstrained optimization studies. A five-p arameter voltage model was assumed, so the result of the estimation wa s a parameter vector, consisting of the following unknown parameters o f the voltage signal processed: its DC component, magnitude, phase ang le, frequency and its rate of change. To demonstrate the performance o f the algorithm, off-line computer simulation results are presented. T he algorithm showed high measurement accuracy over a wide range of fre quency changes. The algorithm 'order two convergence' provided a very good dynamic response as well as a fast algorithm adaptability. The ne w algorithm seems to be a particularly useful tool in the field of fre quency relaying as well as in various aspects of power engineering app lications.