Comparative Study of Reducing the Fault Current and Overvoltage in a Distribution System in Autonomous Micro Grids Operation Using PSO UPFC & SFCL

Abstract

This paper deals with a hybrid active power filter with injection circuit (IHAPF). It shows great promise in reducing harmonics and improving the power factor with a relatively low capacity active power filter. This paper concluded that the stability of the IHAPF based on detection supply current is superior to that of others. To minimize the capacity of IHAPF, an adaptive fuzzy dividing frequency-control method is proposed by analyzing the bode diagram, which consists of two control units: a generalized integrator control unit and fuzzy adjustor unit. The generalized integrator is used for dividing frequency integral control, while fuzzy arithmetic is used for adjusting proportional-integral coefficients timely. And the control method is generally useful and applicable to any other active filters. The strategy was proposed for four- and three-wire systems, and it allowed the compensation of current harmonics and reactive power of harmonic current source and harmonic voltage source loads. Compared to other IHAPF control methods, the adaptive fuzzy dividing frequency control shows the advantages of shorter response time and higher control precision. The simulation results show that the new control method is not only easy to be calculated and implemented, but also very effective in reducing harmonics.