Loading...

Optimal Multicriteria Design of HTS Transformer and Construction of a Laboratory Scale Sample

Moradnouri, Ahmad | 2020

642 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52611 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Vakilian, Mehdi; Fardmanesh, Mehdi; Hekmati, Arsalan
  7. Abstract:
  8. Employing high-temperature superconducting (HTS) tapes, instead of copper or aluminum wires for winding in a superconducting transformer, results in a series of significant advantages; such as: smaller volume, lighter weight, higher efficieny, greatly extended overload capability, better voltage regulation, lower life cycle cost, fault current limiting capability, lower environmental pollution and lower risk potential against fire hazards.In this thesis, optimal design of flux diverter using genetic algorithm for axial short circuit force reduction in HTS transformers has been performed. Then, multilayered flux diverters have been proposed for reduction of weight and losses. The impact of multilayered flux diverters on critical current of the employed HTS tapes has been investigated. Optimum distributive ratios of multi-segment windings have been determined. Then, multi-segment windings are employed to reduce the axial short circuit forces under “tap-changer” operation in HTS transformers. Insulation design of liquid nitrogen end part of the high voltage bushing of a 230/20 kV HTS transformer has been studied. Stress cone and ring-shaped cutouts have been applied into this design to improving its operation. Electric field enhancement and partial discharge occurrence in liquid nitrogen in presence of gas bubbles and conducting particles have been investigated. The impact of size and shape of conducting particles and nitrogen gas bubbles on partial discharge activities inside liquid nitrogen in HTS transformers have been investigated. Design of a 200 MVA, 230/20 kV HTS transformer has been presented. Then, the output parameters of this design work have been compared with the related parameters of a conventional copper winding transformer. The proposed techniques employed in this PhD thesis have been verified against the finite element method simulation (with COMSOL Multiphysics software) results. These simulations demonstrated an elevated efficiency, lower weight and size, and considerable cost benefit for a HTS transformer, against classic transformers
  9. Keywords:
  10. Leakage Inductance ; Insulation Design ; Partial Discharge ; Short Circuit Forces ; High Temperature Superconductor ; Optimal Design ; Critical Current ; Axial Forces ; Radial Forces ; Multi-Segment Modeling ; Flux Diverter

 Digital Object List

 Bookmark

No TOC