Calculating the Electromagnetic Field and Losses in the End Region of a Large Synchronous Generator Under Different Operating Conditions With 3-D Transient Finite-Element Analysis

The significant losses in the end components due to leakage flux excited by the armature and field end windings can result in partial overheating, and are important for the design of large synchronous generators. This paper describes a method based on 3-D transient finite-element analysis (FEA) to determine the fields and losses in the generator end region. Taking the nonlinear and anisotropic properties and the induced in-plane eddy currents in stator into consideration, the electromagnetic field and loss distributions in the end region are calculated. The method is validated by the agreement between the temperatures predicted by a corresponding 3-D thermal FEA and the temperatures obtained from a physical measurement at different locations in the generator end region. Then, the field and loss distributions in the end components in the open-circuit test condition short-circuit test condition and rated apparent power with a 0.85 lagging power factor, a unity power factor, and a 0.95 leading power factor conditions are analyzed and compared using the proposed 3-D transient FEA method.