Calculation And Research Of Eddy Current Loss In The End Region Of Turbo-generator

With the continuous development of society,the application of electric power has become more and more widespread,and China’s electric power industry has entered a new era of large units and large power development.At the same time,the operation capacity of China’s power grid has to be more and more demanding.Large steam turbine generator its structure is simple,safe and reliable operation,favored by the users,so the requirement of generator capacity is becoming more and more big,but at the same time generator in starting phase ability to reflect the reliability of the motor into phase operation,caused by the end of the end magnetic field structure of eddy current loss is also a difficult problem that nots allow to ignore.Taking the turbo-generator with a power of 177 MW as an example,the end loss of large turbo-generator is studied.Firstly,the eddy current field at the end of the turbine generator is analyzed and calculated.Based on the three dimensional finite element method,the end physical models including stator windings,rotor windings,pressure finger,pressure ring and copper shield are established.The effective permeability is used to deal with the nonlinearity of the material.The relationship between the rated load,the rotor magnetic potential and the space position was determined by iteration.The eddy current field at the end under the rated load is calculated,and the eddy current and the eddy current loss in the end structure are calculated and analyzed in detail.Secondly,the two-dimensional finite element method is used to calculate the magnetic field distribution of the 177 MW turbo-generator under different power factors of 0.85,0.95 and-0.95,and the three-dimensional finite element method is used to calculate the magnetic field distribution and eddy current loss distribution under three different operating conditions respectively,and the magnetic field distribution and eddy current loss of various structural parts such as pressure finger,pressure ring,copper shield,stator core and retaining ring are analyzed and compared.Finally,the relationship between different phase depth and end loss was studied.By comparing the relative length of stator core and rotor core,the influence of the electrical conductivity and magnetic permeability of the end structure on the eddy current loss of the end structure was analyzed.Meanwhile,the influence of the relative permeability of the pressure finger of 1.1,2,5 and 10 on the end loss was accurately calculated.It provides a basis for the selection of end structural parts and improves the operation reliability of large turbo-generator.