The effects of integration intervals on recursive rms and powers measurement in the presence of non-sinusoidal conditions

The effects of integration intervals on recursive rms and powers measurement in the presence of non-sinusoidal conditions are considered. The presence of time measurement intervals of both fixed and variable duration is assumed. Suitable formulas to evaluate the errors introduced by the desynchronization of measurement interval for active and apparent power, power factor and voltage and current rms values are developed. Then, the errors are evaluated in presence of smoothing of the results over a variable number of consecutive measurements by means of proper formulas. Some numerical experiment conclude the analysis showing the improvements of accuracy that can be obtained.