The Wavelet Packet Transform and its application to identify arc furnace current and voltage harmonics

This paper examines the application of Wavelet Packet Transform in identifying harmonics in both the voltage and current waveforms of AC electrical arc furnaces. It takes into account the special behaviour of this type of devices, in terms of load, that leads to voltage and current fluctuations which usually are a source of interharmonics. Possible inaccuracy in harmonics identifying process applying IEC criterion and using the FFT is studied and the results are compared with those obtained by applying the wavelet transform. The study was conducted on both simulated signals and voltage and current waveforms in the meltdown arc furnace of a steel mill.