Power quality improvement of grid connected doubly fed induction generator using STATCOM and BESS

Due to variation of environmental condition, power generated from a renewable source of energy always fluctuates. In the same way, by injection of wind power into the electric grid some power quality may varies because of a wind fluctuating inherent and relatively new types of generators. The measurements and the guidelines indicated in International Electro Technical Commission 61400 Standards the quality of power generated and the performance of wind turbines are derived. As far as the measurements of the generated power quality is concerned while the turbine is connected to an electrical grid there are certain associated powers such as active and reactive powers, flicker, the switching function´s electrical behaviour, voltage swell, harmonics and voltage sag. Their measurements are done according to national and international guidelines. This paper studies the static synchronous compensator and battery energy storage system implementation in order to address the issue of voltage stability in wind farms connected to the distribution network. It has been obtained from the results that the STATCOM-battery combination can be very effective in compensating generator rotor angle oscillations and thus well suited for improving transient stability and the dynamic behaviour of the power system. It should also be noted that in this study the STATCOM provides a real power flow path for battery, but the operation of the battery is independent of the STATCOM controller. While the STATCOM is controlled to absorb or inject reactive power, the battery is controlled to absorb or inject real power. Results obtain shows that, during the voltage sag voltage drops to 0.7pu and after connection of STATCOM voltage will improve to 0.89pu and after applying BESS voltage will improve to 0.95pu.