Medium voltage power conversion technology for efficient windpark power collection grids

Renewables are playing an increasing role for the future electrical energy production. As the respective windparks are growing in size, the efficiency in the power collection network gets of increasing interest. To improve the power collection efficiency in high power windparks, it is proposed to move higher voltage levels closer to the single wind turbines. Especially the medium voltage - high voltage step-up transformers are moved close to multiple smaller wind turbine clusters within the windpark. This concept allows placing each wind turbine cluster optimally in the geographical landscape. Another substantial energy saving can be achieved in case medium voltage power conversion equipment is used at the generator level. This is the prerequisite to allow further efficiency improvements, i.e. the total elimination of the wind turbine transformers. With reasonably high medium voltage levels combined with local DC grids within the wind turbine clusters the highest energy efficiency in the windpark power collection grids can be achieved. A detailed analysis for a close-to-shore 90 MW windpark is shown. With the discussed improvements energy savings in the windpark power collection grid of more than 1.5% are achievable.