Application of the Goertzel Transducer for Reactive Power Parameters Measurement

At present, for the power quality parameters measurement instruments, it is required to measure the following reactive power parameters: reactive power of individual harmonics, reactive power of the main spectral component and reactive power in a given frequency band. Spectral analysis is effective for measuring all these parameters. In the case of measurement of a small number of harmonics, it seems effective to use the Goertzel transducer for solving this problem. The paper considers the methodological errors in the measurement of reactive power parameters associated with the deviation of the signal frequency from its nominal value. An approach is proposed to reduce the error, based on the adjustment of the number of processed samples to the value of the input signal frequency. Expressions are obtained that make it possible to estimate the measurement errors of all three reactive power parameters. The options for the implementation of the Goertzel transducer for solving the specified problem are considered. A separate implementation option is presented, based on adjusting the number of samples to the frequency value. The influence of the instrumental error components of the voltage and current measurement channels (additive, multiplicative, nonlinearity, quantization) on the measurement errors of the reactive power parameters is considered. A simulation model of the measurement transducer is performed in Matlab/Simulink.