Superconducting Generators

Superconducting Generators offer increased electrical efficiency, reduced size, increased system stability, and higher generation voltages. CEG personnel had a lead role in the mechanical design of an innovative Spiral Pancake armature winding for a 300 MVA superconducting generator.

Unlike a conventional generator winding where the core has iron teeth and the armature coils are disposed in slots, the winding in a superconducting generator sits in an “air-gap” between the rotor and an iron flux shield. For the 300 MVA superconducting generator, the six armature coils were pancake wound and were interleaved together in a spiral configuration. The overall armature winding and flux shield were very orthotropic in their material properties.

Stress and displacement of the armature winding and flux shield were calculated using finite element analysis for steady state and transient electromagnetic and thermal loads.

Vibration mode shapes and natural frequencies were also calculated using cyclic symmetry. Since the iron flux shield is composed of laminations stacked and bolted together, the structure has many natural frequencies lower in magnitude than the traditionally calculated first elliptical mode.

“Thermal Stress Analysis and Design of the Stator of a 300 MVA Superconducting Generator.” IEEE Transactions on Energy Conversion. Volume EC-1. Number 3. September, 1986

“An Axixymmetric Finite-Element Model for Non-Axisymmetric Loads in Large Superconducting Generators.” IEEE Transactions on Energy Conversion. Volume EC01. Number 3

“Vibration Analysis in Large Superconducting Generators Using Cyclic Symmetry.” IEEE Transactions on Power Apparatus and Systems. Volume PAS-103. Number 6. June, 1984

“Thermoelastic Behavior of Thick Glass/Epoxy Composite Laminates.” Journal of Composite Materials. Volume 18. January, 1984.

“Designing Pancake Coils of a Large Superconducting Generator for Electromagnetic and Thermal Loads.” IEEE Transactions on Power Apparatus and Systems. Volume PAS-102. Number 8. August, 1983.

“Viscoelastic Interface Design for Airgap Armature in Large Superconducting Generators.” International Conference on Electrical Machines. Budapest, Hungary. September, 1982