The Application of the Integration-Differentiation Method for the Measurement of the Fundamental Component of the Reactive Power

Abstract

At present, the following concepts of reactive power are observed: reactive power of the fundamental component, reactive power of harmonics and reactive power in a given frequency range. The most important parameter is the reactive power of the fundamental spectral component. In this article the method of the measuring of the reactive power of sinusoidal signal, based on the integration and differentiation of one of the input signal is implemented. The implementation of this measurement method based on the first-order digital integrator and the first-order digital differentiator is taken into consideration. The digital differentiator based on the algorithm of approximation by two samples is considered. The comparison of the considered method with popular method of integration and popular method of continues time delay from the point of view of the measurement error is carried out. The analytical dependence for the calculation of the additional measurement error of the reactive power caused by deviation of signal frequency is obtained. An expression to determine the gain factors of the integrator and differentiator, which allows to minimize the measurement error of the reactive power near the nominal value of the frequency of input signal is obtained. Simulation mathematical modeling by the software package Matlab 7.0 and Simulink 8.0 is performed.