Wang Purui

Influence of rotor structure on field current and rotor electromagnetic field of turbine generator under out-of-phase synchronization

Out-of-phase synchronization (OPS) fault may occur to the turbine generator used in gas-steam combined cycle units, which may seriously endanger the operation stability of the generator unit. To investigate the influences of rotor structure on field current and rotor electromagnetic field of a turbine generator under OPS, a 2-D field-circuit-grid coupled model (FCGCM) of the 150-MW turbine generator is established. By using the established FCGCM, the influences of rotor slot indexing number (RSIN) and magnetic permeability of the rotor wedge on field current under OPS of 180° were studied. A magnetic no uniform coefficient (MNC) was proposed to evaluate rotor magnetic field nonuniformity. The relations of the field current oscillation ratio and MNC to RSIN and magnetic permeability of rotor wedge were investigated. The results could provide a theoretical basis for the electromagnetic mechanism of the turbine generator under OPS faults.

Effect of inverter fault on distribution of electromagnetic field for permanent magnet synchronous motor

Safe and reliable of inverter is directly related to the normal operation of permanent magnet synchronous motor drive system. Therefore, in the paper, taking a 12.5kW Permanent Magnet Synchronous Motor (PMSM) as the research object, two-dimensional transient electromagnetic field calculation model based on vector control strategy is established, and the corresponding assumptions and boundary conditions are also given. By adopting field circuit coupled calculation method, electromagnetic field is theoretically calculated under inverter normal and short circuit fault (SCF) in the upper switch of phase A, respectively. Simultaneously, due to the SCF, DC components are produced in three phase current, and the influence of the magnetic field produced by DC components on air gap magnetic field is analyzed in detail. In order to validate the accuracy of the established calculation model, some relevant experiments have been conducted. The obtained conclusion can provide theoretical basis for drive system fault diagnosis of PMSM.

Influence of Rotor Structure on Field Current and Rotor Electromagnetic Field of Turbine Generator Under Out-of-Phase Synchronization

Out-of-phase synchronization (OPS) fault may occur to the turbine generator used in gas-steam combined cycle units, which may seriously endanger the operation stability of the generator unit. To investigate the influences of rotor structure on field current and rotor electromagnetic field of a turbine generator under OPS, a 2-D field-circuit-grid coupled model (FCGCM) of the 150-MW turbine generator is established. By using the established FCGCM, the influences of rotor slot indexing number (RSIN) and magnetic permeability of the rotor wedge on field current under OPS of 180° were studied. A magnetic no uniform coefficient (MNC) was proposed to evaluate rotor magnetic field nonuniformity. The relations of the field current oscillation ratio and MNC to RSIN and magnetic permeability of rotor wedge were investigated. The results could provide a theoretical basis for the electromagnetic mechanism of the turbine generator under OPS faults.

Influence of magnetic slot wedge on electromagnetic parameters and magnetic field distribution of turbo-generator

The working performance of an electric machinery can be improved by adopting magnetic slot wedge on the stator or rotor. To investigate the influence of the magnetic slot wedge on magnetic field distribution and the saturation reactance of a turbo-generator, a 2-D mathematical model for electromagnetic field of a 150MW air-cooled turbo-generator has been established by considering two different types of rotor slots. It is put forward that using weakly magnetic Cr-Ni alloy slot wedge and high-strength electric magnetic Fe-Cu alloy slot wedge to replace common A1 alloy slot wedge to improve the static stability performance of the generator.

Stator temperature field of large-scale air-cooled turbine generator considering main insulation shelling

Taking a 2 poles 150MW air-cooled turbine generator as an example, considering the unequal strands and tapered sectional area of upper and lower windings, FIELD coefficients of stator windings are calculated, and corresponding stator copper losses is determined. Then 3D fluid-solid coupled heat transfer model is established. 3D finite element method is applied to study the stator temperature distribution of large-scale air-cooled turbine generator with different shelling degrees of the stator main insulation. The temperature changing regularity of the shelling gaps is also studied.