Frequency Measurement in Power Systems: Accuracy of Classical Electronic and Signal-processing-Based Instrumentation

In this paper the accuracies of the power system frequency measurements achieved by means of commonly used electronic instruments for this purpose are compared with those achieved by means of different state-of-the-art algorithms through experimental results. The used electronic instruments are a universal counter and a bench top digital multimeter. A frequency-domain based algorithm and a time-domain based algorithm are considered. The former one is an Interpolated Discrete Fourier Transform (IpDFT)-based algorithm, while the latter one is the Linearized MultiHarmonic Sine-Fit (LMHSF) algorithm. The comparison is performed under steady-state conditions by using both synthetized and real-life electrical waveforms. From this comparison very useful remarks are drawn.