Loss, Thermal and Mechanical Responses of Rotor in Marine Generators Under SISC Degree and Load Variation

The electric power supply on marine ships depends on the generator. Once the generator fails, it affects the operation of the marine ships. Stator interturn short circuit (SISC) is a common electrical fault in generators. In the case of a short circuit fault, the generator will be in the reinforced exciting current (REC) mode. At present, most research results mainly focus on fault detection methods, rarely concentrating on rotor temperature properties. In this article, the air gap magnetic flux density (MFD) model in the combination of different loads and SISC degrees is established, and the characteristics of the terminal voltage are presented. Moreover, the change rule of the stator current, MFD, and the loss of rotor are comprehensively investigated while considering REC mode. To reveal the law of the rotor thermal response and the biggest value of the deformation/stress/strain at the rotor core acted by temperature, the multiphysics field analysis model with electromagnetic-temperature-structure coupling is established. Experiments are carried out to verify the theoretical and finite element analysis (FEA) correctness by a 5 kW prototype generator.