End-Winding Inductances of MVA Machines Through FEM Computations and IEC-Specified Measurements

Correct finite-element method (FEM) computations of end-winding leakage inductances of MVA-range machines are discussed. This is shown through validations against total stator reactance measurements of 11 air-suspended stators and a reasonable agreement of FEM computations with the International Electrotechnical Commission 60034-4 standard. To achieve this goal, the need to have several 2-D and 3-D FEM models, including those representing the cooling ducts, is emphasized. Steps to utilize the validated stator FEM models for direct computation of end-winding leakage inductances are also listed. It is also shown that measurements of zero-sequence reactances cannot help the FEM validations and do not provide a reliable estimation of the leakage inductances.