Frequency Insensitive Digital Sampler and Its Application to the Electronic Reactive Power Meter

This paper presents the new reactive power (RP) measurement algorithms and their realization on the electronic elements. The proposed Walsh function (WF) based algorithms simplify the multiplication procedure to evaluate the reactive components from instantaneous power signal. The advantages of the proposed algorithms have been verified by experimental studies. One of these advantages is that in contrast to the known existing methods which involve phase shift operation of the input signal, the proposed technique does not require the time delay of the current signal to the pi/2 with respect to the voltage signal. Another advantage is related to the computational saving properties of the proposed algorithms coming from use of the Walsh Transform (WT) based signal processing approach. It is shown that the immunity of the measurement results to the input frequency variation can be obtained if the sampling interval of the instantaneous power is adopted from the input power frequency. Validity and effectiveness of the suggested algorithms have been tested by use of a simulation tools developed on the base of "Matlab" environment.