Coordinated control of HESS in Wind power systems

Energy storage systems contribute to improving power quality of systems which have large penetration of renewable sources. This paper discusses the use of a hybrid storage system that can be controlled to work in coordination with a small capacity wind farm. Their control has been designed in such a manner as to reduce the cycling of one device and increase its life span when used to smoothen the power output of a wind farm. A flywheel and battery based hybrid system is studied where the battery charges or discharges as required with lower frequency profile as compared to the flywheel. Frequency based methods are used to find the cut-off frequency which determines the power reference fluctuations of each device. Results show that power smoothing is possible and therefore wind power systems can be made to behave as conventional generators. The work has been done in DIgSILENT PowerFactory.