Application of Simulink Software for Simulation of Reactive Power Measurement by Integration and Differentiation Technique

Currently, the reactive power of the fundamental spectral component is the most popular parameter at the problems of measurement, control and registration of reactive power. At the problems of reactive power measurement to the measurement error of this parameter the requirements are higher. To measure the reactive power of the fundamental spectral component, techniques for measuring of the reactive power of the sinusoidal signal can be applied. However, under the conditions of signal frequency deviation, the application of most popular techniques does not provide for the required measurement accuracy. The article describes the known technique of reactive power measuring based on the application of a differentiator and integrator. Analytical expressions are obtained to estimate the measurement error by this technique by the conditions of polyharmonic voltage and current as well as the deviation of the input signal frequency. The parameters of the second-order integrator and the second-order differentiator are determined, at which the measurement error is minimal. The simulation mathematical modeling package Simulink 8.0 is used to build a model of reactive power measuring transducer that allows to estimate the methodical error of reactive power measurement. The system of automatic control of the integrator and differentiator coefficients is proposed, which allows for a significant improvement of the measurement accuracy.