Total Stator Copper Loss Calculation in large Synchronous Generators with Hybrid Modeling

This paper calculates AC losses in the stator winding of large generators. In large generators, copper loss in the stator winding consists of conventional copper loss known as DC copper loss, AC copper loss which is due to the AC current passing through the conductors and causing eddy current in the conductors, and additional loss called Circulating Current (CC) loss which caused by using parallel strands in the coil of generators to diminish eddy current loss in stator winding of large generators. The exact calculation of AC and CC loss beside DC loss is crucial for the thermal analysis of the machine because they are determinative and considerable. Hence in this paper, an analytical model is presented to calculate DC, AC and CC loss simultaneously. To feed the inputs of the presented model, Finite Element Model (FEM) is used which creates a hybrid model for finding DC, AC and CC losses. In the end presented model was validated by FEM. Then it is used to calculate the stator winding loss of a 120MW synchronous generator.