Design of a System for Automated Measurement and Statistics Calculation of Voltage and Current Harmonics

The design and operation of a portable, personal computer-based system for the measurement and processing of data on 60 Hz. and harmonic current and voltage amplitudes and phases, and for the production of statistics and time trends on those quantities is described. Over the data acquisition interval, which may be several days in length, the system calculates and stores for each selected harmonic frequency of each selected voltage or current channel, statistics chosen from among: Mean, Mean Square Value, Variance, Maximum, Minimum. Trends in composite quantities such as Telephone Influence Factor and Total Harmonic Distortion may also be calculated over the interval. Samples of the graphical presentation of statistical results are included.