Determination of waveform parameters for short-time a.c. voltage and current generated by IEC 61083-4 TDG

A software requirement standards by IEC is now in draft stage. The publication has already been nubered as IEC 60183-4 which regulates software analysing digitally measured a.c. and d.c. data. TDG (Test Data Generator) like IEC 61083-2 comes with IEC 61083-4. A software used in accreditation laboratory or higher class has to process TDG data within reference values specified in the IEC standards. Authors could develop fast, precise algorithms to process TDG data. Each technique is summarised as: 1) Digital filter for eliminating superposed noise, 2) Fast Fourier Transform for analysing periodical waveform (steady a.c.), 3) an introduction of fitting curve for a.c current interruption and 4) proposal of low-pass filter used to eliminate high frequency noise. The third yields a set of non-linear equations which can be solved by Levenberg-Marquardt Method. The distilled parameters for short-time a.c. are confirmed to be much smaller than the margins (0.1% in peak value) even with a large noise superposed.