Research of Metrological Aspects of Apparent Power Measurement

Apparent power is an important power quality parameter. The method discussed in the article is very popular in practice for measuring RMS and, accordingly, apparent power. Low measurement error is achieved by using a number of techniques: initial phase adjusting or samples number adjusting to satisfy the condition of multiplicity of the signal period and the total evaluation period. The main disadvantage is associated with a fairly long evaluation time. The paper proposes an approach that makes it possible to reduce the measurement time by half compared to those used in practice while maintaining high metrological characteristics. The obtained analytical expressions allows to estimate the final error in measuring the apparent power by the method under consideration. An additional analysis of the influencing quantities (observation time, sampling frequency and other) on the error of measuring of the apparent power was carried out.