Analysis of power consumption presents a very important issue for power distribution system operators. Some power system processes such as planning, demand forecasting, development, etc.., require a complete understanding of behaviour of power consumption for observed area , which requires appropriate techniques for analysis of available data. In this paper, two different time-frequency techniques are applied for analysis of hourly values of active an d reactive power consumption from one real power distribution transformer substation in urban part of Sarajevo city . Using the continuous wavelet transform (CWT) with wavelet power spectrum and global wavelet spectrum some properties of analysed time series are determined. Then, empirical mode decomposition (EMD) and Hilbert -Huang Transform (HHT) are applied for the analyses of the same time series and the results show ed that both applied approaches can provide very useful information about the behaviour of power consumption for observed time interval and different period (frequency) bands. Also it can be noticed that the results obtained by global wavelet spectrum and marginal Hilbert spectrum are very similar, thus confirming that both approaches could be used for identification of main properties of active and reactive power consumption time series .

This paper contains computing and measuring results of start-up, step load, braking and reversing performance of the induction motor. Computing of dynamic states was carried out using idealized mathematical model of the induction motor. The measuring of the dynamic characteristics of the induction motor was carried out with U/f power converter. The load of the induction motor is realized with eddy current brake. The results of computing and measuring are presented and compared.