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.

In order to more accurately and efficiently determine the loss and heating state of the magnetic pole area of a tubular hydro-generator, this study establishes a comprehensive 3D electromagnetic field-thermal network analysis model of its pole area and implements calculations according to its rated symmetrical operating conditions. A 36 MW large tubular hydro-generator is used as an example. Based on the measured results of the pole temperature and the use of the calculation hardware, the results are compared with the traditional electric circuit-magnetic circuit-thermal circuit method and 3D electromagnetic field-temperature field finite-element method. It is shown that the 3D electromagnetic field-thermal network model established in this study has several advantages, including high calculation accuracy, short calculation time, and low hardware consumption. These results have important value in improving the electromagnetic-temperature analysis and design of poles in large hydro-generators.

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Collision detection in Vega Prime is based on the simple line segment, and collision detection based on bounding box is not realized. By studying the composition of three-dimensional object, we define a collision detection class, which inherits from vplsector. After finding out all vertices of geometry in object, we connect these vertices one by one and constitute a trend line. The trend line constitutes our bounding box. Now, our collision detection is based on three-dimensional objects, but not the simple line segment.Additionally, we can expand x, y, z in all vertices in proportion and achieve early warning mechanism in virtual reality