Coordinated Control Strategy for Hybrid Wind Farms during network unbalanced and Short Circuit Condition

Abstract

There is significant increase in the penetration of renewable energy based power generation in the conventional power grid across the world. Wind energy and solar energy based generation is gaining popularity. The thesis focuses on the wind energy. Various technical issued associated with large wind penetration includes change in short circuit level, change of inertia, increase of T & D losses, network unbalance etc to name a few. Wind farms have different types i.e. fixed speed and variable speed. This project investigates a control strategy for a hybrid wind farm comprising a Fix Speed Induction Generator (FSIG) and Doubly Fed Induction Generator (DFIG) based wind turbines under symmetrical and asymmetrical fault conditions. The system comprises of FSIG and DFIG based wind farm connected with infinite bus is considered initially. The 3L-G fault is created at PCC and the results were observed. The literature suggests various control strategy for hybrid wind farm to improve the systems performance and one of the technique is to re-enable RSC (Rotor side converter) of DFIG before the fault is cleared to improve the voltage and reactive power requirement of the system. The same concept is used by using the switching action of crowbar before the fault is cleared. The results are compared with the conventional system. The same concept is used for WSCC 9 bus system under L-G fault and the system performance is compared with the conventional WSCC 9 bus system.