THE APPLICATION OF MULTIRATE DIGITAL SIGNAL-PROCESSING TECHNIQUES TO THE MEASUREMENT OF POWER-SYSTEM HARMONIC LEVELS

The concepts of filtering and sampling power system voltage and curren t signals for harmonic analysis using the fast Fourier transform (FFT) algorithm are introduced. The application of a multi-rate digital sig nal processing technique for harmonic analysis is then discussed and t he design of a polyphase decimation finite impulse response (FIR) filt er, for use as an anti-aliasing filter in oversampling applications, i s covered. The implementation of this filter in conjunction with an FF T by a digital signal processor is described, and results of timing te sts on the algorithms are presented. The instrument used to implement these techniques is CHART - an advanced data acquisition and parallel processing system aimed specifically at continuous real-time power sys tem signal monitoring.