Parameters determination for a.c. voltage and current waveforms: IEC 61083-4 TDG Waveform analyses

IEC 61083-4, which is to be completed in 2013, defines requirements for a software which analyses a.c. and d.c. waveform parameters distilled from digitally measured data. TDG attached to the 61083-4 simulates digitally recorded data for typical waveforms observed in daily measurement. Any acceptable software can determine waveform parameters within a given margin specified in IEC 61083-4. Authors could successfully analyse all the a.c. waveforms generated by the TDG (Test Data Generator) using techniques, 1) FFT after an interpolation for steady a.c. and 2) curve fitting for short-term a.c.. The latter involves the least square method and a set of nonlinear equations. The distilled parameters are within the specified margins proposed in IEC 61083-4. The details of the algorithm are to be clarified in the paper. Also mentioned in the paper is a proposed TDG´s controversial behaviour in which a current-zero instant is shifted due to a discrete sampling interval (note: IEC 61083-4 is presently a draft and has to be rectified on such problem).