Voltage waveform distortion measurement caused by the current drawn by modern induction furnaces

Modern induction furnace draws heavy current with considerable distortion in the current waveform. This heavy distorted current causes distortion in the system voltage. Owing to the insulation limitations at 11 KV line, it is very taxing for modern power quality analyzers to capture the exact distorted voltage waveform. However the distorted waveform of current with high amplitude, drawn by induction furnace, can be captured by these analyzers by virtue of the appropriate CT ratios of their current clamps. By using the FFT of the distorted current waveform, a new mathematical approach using MATLAB has been developed in this paper for the exact modeling of distorted voltage waveform resulted in by distorted current waveform. Finally, this new approach has further been worked out to derive mathematical relation to compute the THD_v which also shows its trend as a function of distance between the supply (utility) and Induction furnace load.