Research on Variation Characteristics and Influencing Factors of Rotor Eddy Current Loss in Nuclear Power Half-speed Turbo-Generator Asymmetrical Operation

In order to research the variation characteristics and influencing factors of the rotor surface eddy current loss during the nuclear power half-speed turbo-generator asymmetric operation, the harmonics characteristics of eddy current generated by stator negative sequence current on the rotor surface are derived by analytical method, and the harmonic characteristics of excitation current generated by stator negative sequence current on excitation winding are derived. On the basis, the harmonic current characteristics of stator winding caused by the harmonic component of excitation current are derived. Furthermore, the eddy current characteristics on the rotor surface caused by the harmonic current in the stator current are derived. At the same time, the influence factors and distribution characteristics of eddy current and eddy current loss of rotor damping strip and slot wedge are given. On this basis, taking a 1407MVA nuclear power half-speed turbo-generator as an example, the field-circuit coupled model is established. The normal and asymmetrical operation of the generator is simulated. Through the comparison and analysis between simulation results and theoretical derivation results, the correctness of theoretical derivation is verified. A theoretical reference for researching mechanism and influencing factors of rotor surface loss during nuclear power half-speed turbo-generator asymmetrical operation is proved.