Analysis of various energy storage systems for variable speed wind turbines

Wind Energy is an intermittent and unpredictable resource. During the high penetration of wind power into the power grid, wind turbines can affect power quality substantially. Voltage fluctuations or flicker, Harmonics and Inter-harmonics, and Voltage drops are all present in this environment. Subsequent affects on active and reactive power, can lead to degrading of grid protection and increased reconnection time. Energy storage systems (ESS) with variable speed wind turbines (VSWT) such as a Doubly Fed Induction Generator (DFIG) or a Permanent Magnetic Synchronous Generator (PMSG) could be a solution to improving the power quality resulting from the “variability” of wind output power. This paper describes the performance analysis of different Hybrid ESS´s (Battery ESS, Super Capacitor ESS and Electrical Dual Layer Capacitor ESS) connected to two different models of 2MW, 60Hz VSWT´s to improve the power quality measured in terms of Total Harmonic Distortion (THD). From simulation results, a Proposed Hybrid System is shown to be a solution in overcoming the problems of high THD and hence the improvement of power quality. Simulation studies have been carried out on a Power System Computer Aided Design /Electromagnetic Transients Direct Current (PSCAD/EMTDC) to compare and verify the system performance under different scenarios.