POWER QUALITY IMPROVEMENT IN THREE PHASE GENERATION SYSTEM USING SHUNT ACTIVE POWER FILTERS

Nonlinear loads in commercial, industrial, and residential applications require the supply of harmonics power, reactive power, and power losses and to minimize the effects of nonlinear loads in electric power systems different solutions have been proposed. In fact, there arenumerous types of compensators proposed to raise the power system quality. One of those compensators is the active power filter (APF). Frequently, the voltage source is chosen to implement the parallel active power filter. Here, APF in shunt isexplored to compare PQ and DQ control theories used in Active power shunt filters. A three phase generator with R.M.S source voltage of 400 and frequency 50 hz is used for electricity generation and a combination of nonlinear loads using R-L and bridge rectifiers is used for consumption. A three phase circuit breaker is used to on-off the filtering circuits as 0.5 second of the total 1 sec simulation time. Current, voltage a power waveforms both at source and load end has been taken for the analysis. Total harmonic distortion (THD) for the current waveform at the source end has been analyzed for three different systems in which first system there is no APF in the circuit. Second two circuits contain APF’s that used PQ and DQ control theories for compensating currents. Fast Fourier Transform (FFT) has been used for currents by taking 21 harmonic orders. System without APF’s gives THD of 10.85% whereas PQ and DQ based APF’s gives 2.093% and 1.665% total harmonic distortion. It has been found that DQ control based APF’s are more effective than PQ method.