Development of No-Insulation Racetrack Coils Wound With 2nd Generation HTS Tapes for a Stator System for Wind Generators
Fabian Schreiner, Yingzhen Liu, Yuanzhi Zhang, Roland Gyuráki, M. Noë, Martin Doppelbauer
Abstract
With the high current carrying capacity of second generation superconductors the increase of power density of electrical devices is a main research subject in the field of superconductors application. Especially, compact and more lightweight generators in offshore wind turbines would result in a reduction of the levelized cost of energy. To avoid the use of cryogenic liquids and reach temperatures below 77 K a conduction cooling method for keeping the coils at their operating temperature is envisaged. Furthermore, the possibility of an increased thermal and electrical stability of coils without a turn-to-turn insulation could make the need of a complicated and sensible quench protection system redundant. To expedite the use of such coils in a real power application the design and construction of a 10 kW laboratory generator demonstrator is set as an objective. Therefore, a pancake racetrack coil is designed for the usage in the stator system of such a demonstrator and wound without any insulation between the turns. The performance of this coil, especially under conduction cooled conditions below 77 K, is investigated. The first results in terms of effectiveness of the cooling system, recording the typical parameters of no-insulation coils and investigating the thermal and electrical behavior at dynamic load situations is presented.