A Novel Method of Voltage Sag and Swell Estimation for Power System Applications

This study presents four simple mathematical models to build the voltage shape with the knowledge of few parameters and detects voltage sag and swells accurately. Fourier series, cubic polynomial, Rational functions and Sum of Sin functions are used in this study to model the voltage profile. A new algorithm is developed to detect sag or swell in all the four models. The voltage estimation due to cubic polynomial has more voltage error and then rational function. The sum of sine function and Fourier series functions does accurate voltage estimation. Errors due to various functions are also tabulated for one electrical cycle. The performance of each method has been compared with other to know the effectiveness of different models and their results are presented.