Measurement and processing of distortion quantities in a portable, multi-purpose analyzer

A wide area evaluation of power system harmonics and interharmonics favours portable, easy to use instrumentation. The authors discuss several topics in this field and report on the construction of a multi-purpose instrument and digital processing algorithms for spectrum-related quantities. It is shown that the numerical processing of signals, sampled at a fixed rate (asynchronous sampling) results in a versatile, uncomplicated construction. Robust and reliable mass memory is realized with nonvolatile semiconductor devices, increasing the effective storage capacity with data reduction and compression techniques. The measured data is post-processed and documented on a desktop computer