Temperature field analysis of the typical faults of nuclear four-pole turbo-generator rotor

At present, the four-pole turbo-generator of ten million megawatts class is widely used in nuclear power plants. Given that the high-speed rotating rotors are prone to many kinds of faults, analyzing the temperature field of the typical faults of generator rotors is helpful in evaluating the influence of faults and the operation ability of the unit with faults. A 3D heat transfer model for the TA-1100-78-type, four-pole turbo-generator was built by using the finite element method. The rotor 3D temperature field distributions of different rotor winding inter-turn short circuit degrees or positions and the blocked rotor ventilation ducts were calculated and analyzed. Results show that the rotor winding inter-turn short circuit fault and blocked rotor ventilation ditch fault of the generator can cause an unbalanced distribution of the rotor temperature field. Thus, the higher the degree of the inter-turn short circuit, the greater the unbalance of the rotor temperature field, resulting in greater temperature increase. Moreover, the closer the position of the inter-turn short circuit is to the rotor teeth, the higher the distortion degree of the rotor temperature field. The influence of the blockage of air holes on the rotor temperature field is related to the blockage position. The blockage of a single duct causes an obvious temperature rise near the blockage point, whereas the blockage of double ducts has little effect on the overall temperature field. The results provide theoretical reference for the design, operation and maintenance of the turbo-generator through the 3D analysis of typical problems. © 2019, Editorial Department of Journal of HEU. All right reserved.