PARAMETRIC HARMONIC-ANALYSIS

Harmonics in power systems is now a subject of wide ramifications. One particular aspect is that of capturing harmonic data at selected loca tions in a power network and processing it to identify harmonics and t o quantify their magnitudes and arguments. Circumstances are encounter ed in practice for which the discrete Fourier transform (DFT) cannot b e relied on the achieve valid harmonic component identification. These are where there are subharmonics, harmonics which are not integer mul tiples of the supply frequency, and where two or more harmonics have o nly small frequency separations between them. The paper reports a new procedure which fulfils the requirements of practical harmonic analysi s. It avoids altogether the limitations of the DFT algorithm and is ba sed on the nomination of a distorted waveform model expressed in terms of a sum of sinusoidal functions. Model parameters are the frequencie s, magnitudes and arguments of the harmonics in the waveform it repres ents. The error between the model waveform and the actual one represen ted in captured form is minimised. At the minimum, the parameters of t he model are those of the waveform for which harmonic analysis is requ ired. A key advance in this parametric form of analysis is that of a p artitioning of the data for the waveform to be analysed into a trainin g set and a test set. This partitioned form of generalised parametric harmonic analysis is thus developed. key concepts are clarified via a numerical example to illustrate how this approach can excel for the ha rmonic analysis in power system.