Research On Protection Technology Of Induction Motor Based On3D Temperature Field Model Of Stator Winding

As the main power source of industrial enterprises, motor play an important rolein the economy construction. High level asynchronous motor protection technologyis always one of the main research directions of electrical apparatus.Establishing an accurate protection model is the key of induction motorprotection technology research. According to the problems of existing inductionmotor protection technology research and application, a more accurate3Dtemperature field simulation model of whole stator was established by solving theinverse problem of heat conduction based on the temperature distribution datameasured in easily measure area. The induction motor stator temperature virtual testplatform is developed based on the model. According to the ideas about themaximum temperature detection and protection of stator, the soft measuringprotection model，the forecast protection model and on-line detection protectionmodel for the maximum temperature of stator winding are proposed. Finally, theprotection program and its implementation based on the model are presented. Theresearch ideas about temperature protection also apply to a variety of motors.The main research contents include:1、This paper made a more detailed overview of the development and currentsituation of motor protection device and the researching situation of motor protectionmodel and related technologies, and point out the problems and developmentdirection of motor protection technology.2、Constructed the induction motor stator temperature distribution measurementsystem, and the actual3D temperature distribution of induction motor stator weretested at typical operating conditions. The causes of the stator3D temperaturedistribution were analyzed in this paper, and ideas were proposed to improving coolconditions and reducing the maximum temperature of stator windings.3、The basic whole stator3D temperature field simulation model was establishedbase on the heat theory of electric motor. Parameters and boundary conditions of thebasic model was anti-calculated by orthogonal test method. Then a more accuratewhole stator3D temperature field simulation model was established. 4、A induction motor stator temperature virtual test platform is developed basedon the3D temperature field simulation model. Steady-state temperature distributionand transient temperature change of the motor under all kinds of operation conditionsare measured by the platform. The temperature distribution and the law oftemperature variation can be studied. This paper also proposes the scheme aboutoptimizing the heat dissipation structure and improving the capability of long-termoverload operation of the motor.5、Following the maximum temperature detection and protection of stator asguiding principle, the soft sensing protection model and forecast protection model forthe maximum temperature of stator winding are proposed based on the lumpedparameter thermal model of stator winding. The key parameters of the models aboveare analyzed and determined by the test platform and experimental results validatethe accuracy of the above model and parameters. Furthermore, the protection modelbased on the on-line detection of the current and the maximum temperature of thestator is established.6、The maximum temperature protection technology of stator winding ofinduction motor is studied. The three protection programs based on soft sensing,forecasting and on-line detecting for maximum temperature of stator winding,respectively are given and the features of the above programs are compared.Obviously, according to the heat theory of the motor, the virtual test platform of3D temperature field simulation model of whole stator is developed in this paperbased on inverse problem of heat conduction. On this basis and according to theprotection principle of maximum operation temperature, a new protection model andprogram are proposed, as well as the measures of improving the rated load capabilityand overload performance. The overall research ideas and results of protectiontechnology for induction motor, which are proposed in this paper, will promote theresearch and application of motor protection technology. It also has a reference forprotection technology researching of other types of motor.