Transient modeling and analysis of a DFIG based wind farm with supercapacitor energy storage

• The studied wind farm consists of a DFIG based on ROM.
• Supercapacitor of ESS component in DFIG is used.
• Nonlinear modeling of supercapacitor is done in the DFIG.
• A comparison of transient events is made between without/with supercapacitor.

Energy storage system (ESS) coupled to a wind generator has been recommended in improving the stability of the power system to which the wind farm is connected. ESS is particularly preferred in enhancing low voltage ride through (LVRT) capability owing to its fast charging and efficiency for high power applications. In the present study, a supercapacitor type ESS is used in transient state analysis of a grid connected wind turbine. The ESS consisting of a supercapacitor and a voltage buck-boost converter circuit is mathematically modeled in the grid side converter circuit of a doubly fed induction generator (DFIG) used as a wind generator. Moreover, reduced order model (ROM) for the DFIG is used in simulating stator dynamics. All modeling study has been carried out in MATLAB/SIMULINK environment. Three phase faults and having static loads for a short period of time are considered as transient cases. The effectiveness of the ESS on LVRT are shown by observing the responses of several system parameters. The study results show that utilizing a nonlinear supercapacitor type ESS in a ROM based DFIG removes oscillations in a short time during transient states, therefore enhances LVRT.