Analysis Of Electromagnetic Force In Large Nuclear Power Turbo-generator In The Open-phase Operation Condition

The nuclear power turbine generator is the core component of the nuclear power generation system,and the safety and reliability of its operation is very important for the operation of the whole power system.With the rapid development of nuclear power generator technology,the turbo-generator of nuclear power is becoming more and more massive,and the capacity of the generator is constantly breaking through.At the same time,non-full-phase operation is a kind of lack of phase running state,which is a serious asymmetrical operation fault of the generator.It is also one of the most adverse events in the operation of the power system.Therefore,it is of great importance to analyze the dynamic electromagnetic force of the nuclear turbine generator and find out the local stress concentration,and improve the design of all parts of the motor.The study object is a nuclear power turbine generator with a capacity of 1407 MVA in this dissertation.In order to simplify the process of solving,we have to make the appropriate assumptions about the motor.Then,the mathematical model and constraint conditions of the transient electromagnetic field of generator are established.The two-dimensional electromagnetic field model of the generator is set up by the finite element software,and the motor network-running external circuit is built by the software.In order to fully reflect the real situation of the motor running,the speed and excitation system need to be properly controlled,so the excitation control and speed control module are added.In this dissertation,compared in rated condition,the dynamic electromagnetic force distribution of the motor at the time of transition state is analyzed.The output parameters of the generator and the variation of rotor magnetic density are analyzed in the two cases.The electromagnetic force distribution and regularity of the special time point of rotor tooth of motor are analyzed in detail by Maxwell stress method.Then,the change of magnetic stress in the time domain is analyzed and compared with the rated time.On the basis of analysis of air-gap flux variation characteristics under the open-phase operation condition,and fourier transform and other methods are used to analyze the characteristics of its changes.Then the dynamic distribution and the change rule of the rotor radial and tangential magnetic force wave are given.In this dissertation,the distribution of electric magnetic force of the motor under the condition of the stationary operation in the open-phase operation condition and in the rated operation of the motor are analyzed.The output parameters of the generator and the characteristics of the magnetic density distribution are analyzed when the motor enters stable operation.The electromagnetic force distribution and regularity of the stator tooth of the motor are analyzed in detail combined by the Maxwell stress method.Furthermore,the stress changes of the key points of the stator tooth in the time domain are analyzed.The change of the magnetic stress in the time domain is analyzed and compared with the rated condition.To sum up,this dissertation both studied the distribution and regularity of electromagnetic force in the space-time domain of rotor when the turbine generator is running in transient mode in non-full phase operation condition,and studied the distribution and regularity of electromagnetic force in the time-space of the stator when the turbine generator is running in steady state in non-full phase operation condition.This study provides parameters for motor design and manufacturing to guarantee the mechanical strength of the motor components,so as to ensure that the rotor is not damaged when the motor is running in non-full phase operation condition.It provides theoretical basis for optimizing design and manufacturing,installation and maintenance,operation and operation of large turbo generator.