Techniques to Accelerate Power Quality Analysis Based on DWT

The paper deals with techniques to accelerate the DWT power quality analysis. Firstly a non-spline interpolation schematic is proposed for the evaluation of the first components near the right border of the signal. Comparisons are made between power quality indices, shape of details waveforms and runtimes, considering 3 cases. The first 2 cases correspond to data acquired on stand and correspond to a driving system using chopper and DC motor. The 3rd case deals with sets of currents and voltages acquired from the secondary winding of the excitation system used to supply a generator. 4 methods were used for calculation. The 1st one - FFT, is used to generate "reference data". The others rely on 3 distinct original functions used to implement DWT using a Daubechy filter of length 8. The 1st function does not use interpolation, the 2nd one uses spline interpolation and the 3rd one, uses interpolation relying on mean slopes. Similar results were generated by all methods, but the newly introduced function, especially useful when the analyzed signal's periodicity is questionable, exhibited halved runtimes. Finally an original multithreading technique is presented. Savings of 45% of runtimes were revealed by tests.