Calculation to Short-Circuit Mechanical Strength for Powerformer Windings
Wang Shishan(1),Ji Shengchang(2),Li Yanming(2)
(1 Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China) ( 2 Xi'an Jiaotong University, Xi'an 710049, China)

Abstract:The initial conditions and the time corresponding to most serious state s of short-circuit were deter mined based on the Tmodel of power transformer. Considering the conditions as voltage at primary winding, short-circuit forces of windings and turns for transformer were calculated with FEM coupling circuit method under the 2D symmetrical model. Focusing the turn subjected to the maxim umaxial and radial forces, the static and dynamic finite element models were presented for the single turn, and the stress distributions were calculated under static and dynamic states respectively. The relationships of equivalent stress with prepress and spacer numbers were discussed, and the equivalent stress via time was investigated comparatively.
Keyword: powerformer, short-circuit magnetic force, finite element method, mech anical strength.