Measurement of Reactive Power in Three-Phase Electric Power Systems by Use of Walsh Functions

Abstract—This paper presents a new method for measuring of three-phase reactive power (RP) in three-phase systems. Extraction of three-phase reactive power RP from entire instantaneous power signal is achieved by multiplication the phase instantaneous powers with the Walsh function(WF). This method simplifies the multiplication procedure required for the evaluation the tree-phase reactive power components due to the use of the peculiar properties of the WF. In contrast to the existing methods involving phase shift operation between the input voltage and current signals proposed measurement approach does not require the phase shift of the phase current signals to the 2/π with respect to the voltage signals. Limitations and proposals for future performance enhancements of the suggested method are also discussed. Validity and effectiveness of the suggested method have been tested by use of a simulation tools developed on the base of “Matlab 6.5”. The results obtained demonstrate that the computational demands can be substantially reduced by using the proposed method. Index Terms—reactive power, measurement, unbalanced three-phase systems, analog signal processing, DSP, instantaneous power signal, Walsh function, phase shift. I