One phase overload or lightload condition is a very common condition in nuclear power turbo-generators, and magnetic field distortion and current asymmetrical degree concern the safe operation of turbo-generators. Damper and wedge windings are the special parts that distinguish the nuclear power generators from other smaller generators. Therefore, it is extremely important to investigate magnetic field distortion and stator electrical quantity. At the beginning, taking saturation and slot effects into account, the finite element model of a 1400MVA nuclear power generator is built up. And through comparison between the finite element simulation and the experimental results of no-load characteristics and short-circuit characteristics, the effectiveness of the finite element model was fully tested. Then, with or without damper and wedge windings, and leakage flux, the negative sequence equivalent circuit is employed to explain the law of magnetic field distortion under stator negative current, which is also verified by finite element simulation. Based on a novel theory proposed in this article, the law of the stator positive and negative sequence current, and the current asymmetrical degree with alteration of one-phase load under steady state are given in detail. Additionally, the finite element method is developed to test the correctness of the novel theory. The influence of damper and wedge windings, leakage flux at coil ends, and eddy current on the solid magnetic-pole of rotors on stator electrical quantity is also discussed in detail.Lv Pin (Non-member) was born in Harbin in China, on November 8, 1989. She graduated from Harbin University of Science and Technology and obtained her master and doctor diploma there. Currently, she is working at Heilongjiang University of Science and Technology. She is doing her postdoctoral research at China University of Mining and Technology. She is specialized in electric apparatus theoretical analysis, fault diagnosis, and simulation calculation. She also has plenty of knowledge about insulation calculation and smart-grids. Additionally, she is an expert at the new energy machines. Xie Zidian (Non-member) He was born in Hebei in China in 1962. Currently, he is working at Heilongjiang University of Science and Technology as a professor. He is specialized in design and research of microcomputer-integrated controllers for coal mining machine. Zhao Hongsen (Non-member) He was born in Harbin in China, on June 25, 1987. He graduated from Harbin University of Science and Technology and obtained his master and doctor diploma there. Currently, he is working at Lishui University. He is specialized in electric apparatus internal fault diagnosis and protection. Ge Baojun (Non-member) He was born in China in 1960. Currently, he is working at Harbin University of Science and Technology as a professor.He is specialized in the design and research of large generators, pumped storage motor, energy converter, and special motor. Now, he is the chief editor of Electric Machines and Control, which ...