Influence Of Damper Winding Pitch On Rotor Temperature Field

With the rapid development of our country’s economic construction, therequirement of electric power industry increases and the increase of generatorcapacity is an inevitable trend. Under the premise of sustainable economicdevelopment, hydroelectricity capacity becomes a higher proportion of the totalelectricity generating capacity, as its special advantage in economic andenvironmental protection. At present700MW the most capacity hydro generatorhas been put into operation and the new generation1000MW hydro generator isin research and test stages. As one of the most important parts, damper windingnot only play an important role in restraining oscillation effectively but also canimprove the stability of generators and power system. Because of the complexstructure and electromagnetic filed, damper windings generate loss, which willmakes damper windings local overheating, in severe cases, the damper windingswill fusing, flying out of slot even sweeping the stator. So, it is significant toresearch the distribution of damper windings’ electromagnetic field and heatsource. Pointing to this problem, the following job is done in this paper.First, combining actual structure and electromagnetic field theory, the2Delectromagnetic filed model of the hydro generator is built., and the generatorelectromagnetic field is solved by Time Stepping Fem method. Theelectromagnetic field and damper winding eddy current loss are calculated andanalyzed under rated load, and the damper winding loss is obtained. Based onthat, the influences of air-gap changes on damper winding loss is study in thesalient pole generator, and compare the change of damper winding’s eddy currentunder three different kinds of air-gap.Second, according to characteristics of fluid flow and heat transfer in thecooling system of hydro generator, the3D coupling calculation models of fluidfield and temperature field are made, then the basic assumptions and the boundary conditions are given. Based on the damper windings’ eddy current losscalculated through2D electromagnetic field, the coupled calculations for thefluid field and temperature field of the rotor pole are done using the finite volumemethod. Compared with the test data, the calculation results have proved themethod and the model to be correct and effective. Then the fluid field andtemperature field results of a pair of poles are analyzed.The last, to analyze the influence of damper winding pitch on the rotortemperature field, the other two coupling models of fluid field and temperaturefield are made. The comparison analysis of the effect of damper windingarrangement approach on fluid field and temperature field is preceded, anddiscuss the temperature changes of the main parts on the rotor.Some useful conclusions are obtained, which could be beneficial to the furtherstudy on hydro generator optimizing design and improvement of operationalreliability, and is the base of loss analysis, heat and cool research.