【作者】 李林合；

【导师】 梁艳萍；

【作者基本信息】 哈尔滨理工大学 ， 电机与电器， 2006， 硕士

【摘要】 理论上,任何转速的水轮发电机定子绕组均可设计成对称的,但是在实际应用中综合考虑水文条件和电网电压等级的限制时,采用定子绕组对称的水轮发电机并不总是理想的。支路不对称定子绕组的水轮发电机常常会在发电机本身作出一定让步后,给整个发电机组的合理设计带来便利。随着电力工业的发展、单机容量的增长,出现了大容量多支路水轮发电机。这种发电机常常是支路不对称的,发电机各支路的电势、电流和阻抗都将出现差异,这种有违交流电机的设计常规的不对称绕组对电机运行性能所引起的多方面影响的研究还有待深入。特别是当其内部发生短路时,短路电流可能超过出线端最大短路电流的几倍,从而引起严重的电气、机械和热损坏。因此,进一步研究交流电机绕组的不对称理论,弄清它对电机产生的危害以便设计相应的继电保护装置和采用其他措施来减轻这种危害具有十分重要的意义。针对一台大型水轮发电机设计数据,本文首先讨论了支路不对称绕组的连接问题,提出了水轮发电机支路不对称定子绕组的连接方法。通过对支路感应电势不对称度的分析,总结出了绕组连接方案选优依据。在此基础上,为了探讨水轮发电机定子绕组不对称支路参数的计算问题,根据交流电机多回路理论,建立了绕组不对称支路参数计算的数学模型,给出了应用有限元方法计算绕组不对称支路参数的通用方法。分析表明,该方法可用于任何绕组的参数计算,且计算结果较为准确。其次,对水轮发电机定子绕组不对称支路间环流问题进行了探讨,建立了绕组不对称支路间环流计算的数学模型,确定了环流计算方法。并通过对绕组不对称支路间环流损耗的计算,找出了影响支路间环流的因素。最后,对水轮发电机定子绕组不对称支路磁势谐波问题进行了探讨,编制了谐波磁势分析通用程序,提出了不对称支路绕组谐波磁势分析的通用方法;并对所研究电机不对称定子绕组进行了谐波磁势不对称度的分析。更多还原

【Abstract】 In theory, the hydro-generator stator winding of any speed can be designed symmetrically. Considering synthetically the restrictions of the hydrological condition and the voltage level of electric power system in practical application, it is not always ideal to adopt hydro-generator of symmetrical stator winding. The hydro-generator with asymmetric branches stator winding, which it is not at the best operating point, can bring facility to rational design of the generator units. With the development of power industry and the growth of unit capacity, the large capacity hydro-generator whose stator winding is asymmetrical has appeared. When branches of winding are asymmetric, the electric potential, current and impedance of branches winding will be different. The research on the influence of the especial asymmetric winding on electric machine operating characteristic should go farther. When the short-circuit takes place within stator winding, the short-circuit currnet may exceed several times of the largest current, concequently, it will cause serious electrical damage, mechanical damage and thermal damage. So, it is important to study the stator asymmetrical winding, to clarify the influence of the especial asymmetric winding on electric machine operating characteristic, to design relay protection that can lighten the danger.For a large hydro-generator, at first, the asymmetric branches connection of hydro-generator stator winding is analyzed. An asymmetric branches winding connection method is put forward. After analyzing the branches EMF asymmetrical degree, a standard is brought forward. We can know which winding project is the best by the standard. On this basis, to discuss the calculation problem of asymmetric branches stator winding parameters, according to the multiloop theory of electrical machine, a mathematical model of asymmetric branches winding parameter calculation is set up in the paper, a universal method by which asymmetric branches winding electromagnetic parameters can be calculated is given. Analysis indicates, the method can be used in the calculation of electromagnetic parameter of any windings and the result is accurate.更多还原