Numerical calculation of air gap magnetic field of a salient synchronous generator with the consideration of the effect of turn insulation

According to the theory of electromagnetic fields, the air gap magnetic field of a large salient synchronous generator with a fractional stator slot is calculated by the finite element method with and without the consideration of turn insulation in this paper. By analyzing the air gap magnetic field, stray loss on the surface of rotor can be worked out and moreover temperature field distribution in rotor can be obtained. Calculation results with and without the consideration of turn insulation are compared and the effect of turn insulation to the air gap magnetic field and rotor temperature field is analyzed. The Longyang Gorge 320 MW hydro generator is taken as an example and the calculation results and the measured results are compared to test the accuracy of the calculation.