Effect of evaporative cooling of stator core on electromagnetic field of large horizontal generator

The capacity growth of flow-bulb hydrogenerator is limited by heat dissipation conditions. As an efficient cooling method, evaporative cooling technology has been successfully applied to giant hydrogenators. However, due to the size limitation, the evaporation cooling technology which is directly cooled the stator winding in the vertical hydrogenerator cannot applied to the flow-bulb hydrogenerator. This paper introduces a kind of stator iron core evaporative cooling technology, and analyzes its influence of the layout of the cooling tubes on the electromagnetic field. This paper takes a 50MW generator which has been put into operation as the prototype, and sets up four kinds of cooling tubes layout schemes. The electromagnetic field simulation based on time-step finite element method is used to compare these schemes with the prototype. The calculation results show that the reasonably arranged cooling tubes can not only enhance the cooling effect but also not greatly increase the stator iron loss, which is beneficial to improve the capacity.