Recording power demand characteristics and harmonic pollution by a general-purpose data logger

A general-purpose microcomputer based data logger has been configured to perform multi-channel logging of voltage and current in power circuits. Algorithms have been developed to compute the real power, maximum demand and power factor directly from the sampled instantaneous values. The data logger is also capable of snap-shot recording of voltage waveforms by fast sampling. Subsequent analysis by a fast Fourier transform (FFT) algorithm can reveal the extent of harmonic pollution in the supply voltage. Results of measurement in various types of installations are presented