Dynamic Measurements During Short-Circuit Testing of Transformers Part I: Instrumentation and Testing

The instrumentation methods and testing procedures utilized to obtain dynamic forces, displacements, pressures, and mechanical strains on a full-size 19.5 MVA three-phase, three-winding oil-filled power transformer is presented in this paper. Each phase of this transformer was constructed with different insulating materials and different clamping methods; one of these included an externally adjustable hydraulic clamping system. The data obtained on this transformer will add new and fundamental knowledge of the effects of winding prestress, clamping methods, insulating materials, and tap arrangements on the dynamic characteristics of large power transformers during short circuit. This first paper will form the foundation for the data presentation and analysis to be presented in later papers.