Analysis Of Electromagnetic Loss And Thermal Performance For1000MW Hydro-generator

With the development of hydropower technology, the unit capacity of thehydro-generator is constantly expanding, and the heat load is increasing at thesame time. The heat load is directly related to a generator’s economic index,service life and operational reliability. The effectiveness of the ventilation systemis one of the most important factors which impact the generator temperature rise.Owing to high efficiency, simple structure and convenience maitenance, theventilation system without any air fan is applied widely in huge hydro-generators.However, the requirements for designing rationality of ventilation structure isdemanding higher. Therfore, it is necessary to research the ventilation andtemperature peformace for huge hydro-generators. In this paper, a1000MWhydro-generator is studied, moreover, the fluid field in ventilation structure andthe temperature field are calculated.Firstly, the2D ventilation structure model of1000MW hydro-generator is builtaccording to computational fluid dynamics principle, and the fluid field of coolinggas under rated speed is calculated. Three prioritization schemes for pole coilsstructure is put forward. Moreover, the influence of these schemes to ventilationfluid field is contrasted and analyzed.Secondly,3D temperature field models of hydro-generator stator and rotor areestablished according to heat conduction theory. The temperature distribution ofstator is calculated. At the same time, the pole surface additional loss is calculatedby the analysis of generator’s electromagnetic field combining the analyticalformulas. The heat release coefficient of each surface on rotor is determined bythe flow velocity of the cooling air. Based on that, the temperature field iscalculated and the influence of surface additional loss to temperature is discussed.Finally, the influence of different pole coils structures on the temperaturedistribution of rotor is analyzed, and the most appropriate structure is found.All of the conclusions could provide theoretical basis for the designing of ventilation structure and the accurate temperature calculation of hugehydro-generator.