Numerical Modeling of Losses in the Stator Winding of a Large Electric Machine Considering Roebel Transposition

This paper presents a methodology for estimating losses in the winding of a large electrical machine considering Roebel transposition on the example of a 63 MW turbogenerator. The stator winding of a large machine is a complex and expensive unit. During operation it is continuously subjected to complex mechanical, thermal and electromagnetic loads changing in time. A significant part of machine failures is still associated with stator winding failures, such as shorting of elementary conductors, conductor breakage, discharge activity, vibration, etc. Application of modern methods of modeling and research of physical processes is able to advance in solving this problem. The model proposed in this paper allows relatively simple calculation of the loss value at different slot geometry and arbitrary transposition schemes. Moreover, this model can be used for detailed modeling of some winding defects in order to evaluate their influence on the whole machine performance. This study can be useful for specialists in the design and research of large electrical machines.