HVDC  FOR  OFFSHORE WIND FARMS
Author      : R.Sreenath, S.Sathiya Seelan  (III year EEE) Dept         :  EEE College     : Saranathan college of Engineering, Trichy 12   File type   :  DOC Publish     :
ABSTRACT:           Large offshore wind farms are recently emerging as promising alternative power Sources. Long distances between offshore generation and onshore distribution grid demand new solutions for their connection to the AC network. HVDC systems based on voltage source converters (VSC) are a promising alternative to conventional AC transmission above a certain cable length. In this paper, a new soft-switched VSC topology is proposed that promises both lower initial costs and a higher efficiency. As a consequence, the minimum cable length at which VSC transmission gets interesting can be further decreased and the HVDC grid connection of large offshore wind farms gets far more attractive. The operation principle of this new VSC topology is presented with respect to the commutation of the semiconductor switches. The advantages and challenges of the proposed topology are also outlined. Furthermore, a comparison with a state-of-the-art variable-speed wind turbine reveals the potential of this new technology. Thereby, this paper concentrates on the losses and ratings of the converters