The loss and heat of a self-cooling enclosure-isolated phase bus of large generator are studied by establishing the electromagnetic-fluid-temperature field model of the bus using the finite element method. Factors such as skin effect and eddy loss, the electro-conductivity temperature effect, gas flow, and gravity are considered. The compositive calculation and analysis of the loss and temperature of the self-cooling enclosure-isolated phase bus of a 600 MW generator are conducted, and the data are compared with the test. The results show that the current and loss distribution in the conductor and sheath of the horizontal bus correlate with skin effect. The distribution of the bus temperature around the vertical center axis is symmetric, but the temperature of the top bus is higher than the bottom. If the influence of the acceleration of gravity and heat radiation is not considered, the result will become unreasonable.INDEX TERMS Electromagneti-fluid-temperature field, self-cooling separate-phase enclosed bus, loss, heat.

This paper studies a real 36-MW large tubular hydro-generator to solve the transient variation problem of the loss and heat of damper bars during short circuit faults in tubular hydro-generators. The transient analysis method of electromagnetic-temperature fields is adopted to study the transient variation problem of the loss and heat of damper bars during three-phase symmetrical short-circuits, single-phase to ground asymmetrical short-circuits, and phase-to-phase asymmetrical short-circuits under rated operation states. The research work provides valuable findings for improving the level of state analysis, the design and manufacturing processes, and the operation and maintenance of large-scale tubular hydro-generators.

In this study, a 34-MW tubular hydro-generator was selected as the study example. For the electromagnetic field-circuit coupling analysis model, the effects of the ideal DC voltage and current sources (i.e. two models of the rotor excitation power supply) on the no-load voltage waveform quality and the damper winding loss calculation results were studied by considering the influence of the electromagnetic induction of the rotor excitation winding. The obtained results provide direct and effective theoretical support and technical reference for improving the accuracy and rationality of the calculation results of the electromagnetic performance parameters and the analysis, design, manufacturing and operating level of such generators. K E Y W O R D S eddy current losses, electromagnetic fields, harmonic analysis, hydroelectric generators, voltage distributionThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

For the pole shoe and damper winding centre line shifted structure that has been gradually applied in hydro‐generator in recent years, this letter selects one real integer and one fractional slot large tubular hydro‐generator as examples. Then revealed the influence trends of different shift degrees on the no‐load voltage waveform quality and the damper winding loss and heat under rated load conditions. Also, it compared these trends with those of the traditional stator skew 1 slot structure. The results show that for integer slot generator, this kind of shift structure can obtain high‐quality no‐load voltage waveform close to the traditional stator skewed 1 slot scheme, and the damper winding loss and heat is significantly smaller than the latter. For fractional slot generators, this kind of shift structure will lead to the deterioration of the no‐load voltage waveform.

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