Analysis Of Generator Loss Characteristics Under Stator Interturn Short Circuit

The stator core loss and stator copper loss will be generated during the operation of the generator,which will eventually be converted into heat and cause the temperature rise effect of the generator.If the temperature is too high,the insulation of generator winding will be damaged and the conversion efficiency of generator will be affected,especially the stator interturn short circuit fault.Therefore,in order to improve the insulation performance of generators and improve the conversion efficiency of generators,it is essential to study the loss of generators.In this paper,the stator loss and the thermal wear law of the stator winding insulation are studied under the normal condition and the stator interturn short circuit fault in synchronous generators by taking the CS-5 generator as an example.(1)Based on the air-gap flux density,the analytical expressions of the phase current and the stator loss are derived under the normal conditions,faults with different short-circuit degrees between turns and faults with different short-circuit positions between turns,and the change rules of phase current and stator loss under various short-circuit faults are qualitatively analyzed.(2)Using Ansys and Solidworks software,a three-dimensional physical model of generator core-insulation-winding was established,and the electromagnetic characteristics and losses under different working conditions were simulated.Through the coupling solution of magnetic-thermal-solid,the insulation wear degradation law of stator windings was further studied.(3)Finally,the CS-5 fault simulation generator measures the stator temperature.The experimental results and simulation data are basically consistent with the theoretical analysis.The distribution and the rise of the stator temperature should be determined and monitored under the different operating conditions.Meanwhile the peak point of thermal stress of stator winding insulation is determined,which provides a certain reference for the generator design and the stator winding insulation monitoring.