Volume -I , Issue -III, February 2014

VOLTAGE PROFILE IMPROVEMENT USING SERIES HYBRID ACTIVE FILTERS

K. SATISH KUMARdiv>

The increase of nonlinear loads due to the proliferation of electronic equipment causes power quality in the power system to deteriorate. Harmonic current drawn from a supply by the nonlinear load results in the distortion of the supply voltage waveform at the point of common coupling (PCC) due to the source impedance. Both distorted current and voltage may cause end-user equipment to malfunction, conductors to overheat and may reduce the efficiency and life expectancy of the equipment connected at the PCC.An series active filter(SAF), typically consists of a three phase pulse width modulation (PWM) voltage source inverter, when this equipment is connected in series with the ac source impedance it is possible to improve the compensation characteristics of the passive filters in parallel connection.A three-phase series hybrid active filter(SHAF) topology is proposed in this project for improving the voltage profile in a distribution system. It is constituted by a series active filter and a passive filter connected in parallel with the load. The control strategy is based on the instantaneous reactive power theory, so that the voltage waveform injected by the active filter is able to compensate the reactive power and the load voltage harmonics and to balance asymmetrical loads. The proposed algorithm also improves the behavior of the series active filter with the introduction of passive filter. Hysteresis current control PWM method is used for producing switching signals for the switches of voltage source inverter. Simulations have been carried out on the MATLAB-Simulink platform with Non linear load and the results are presented and analysed. The proposed d-q theory effectively produced compensating reference voltage and hysteresis current control PWM method produced the required switching signals to control the switches effectively.The results show that the proposed topology of SHAF improved the voltage quality at the point of common coupling.

Series Hybrid , Voltage Profile , electronic equipment , point of common coupling.

1. P. Salmerón and S. P. Litráns “Improvement of the Electric Power Quality Using Series Active and Shunt Passive Filters ” IEEE Transactions On Power Delivery, Vol. 25, No. 2, April 2010.