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This paper proposes a way to represent the anisotropic nonlinear superconducting properties using a discrete model for magnetization with the corresponding critical parameters, equivalent to the Power Law model for currents. This simplified model makes it possible to analyze magnetic systems with superconducting elements in a stationary mode, which reduces the calculation time. Using of proposed model is demonstrated by the calculation of force interactions between high-temperature superconducting (HTS) samples and permanent magnet in zero-field-cooling (ZFC) and field-cooling (FC) modes. HTS bulks in the form of a prism and stack made of HTS tape are considered. The calculation of the electromagnetic field was carried out using the method of integral equations for field sources. The data of calculations are compared with the results of experimental studies. [ABSTRACT FROM AUTHOR]

The air-cooled turbo-generator often works in the more frequent start-up and shut-down operation. Either the misoperation or the failure of synchronizing controllers can cause the out of phase synchronization fault. The fault can disturb the power angle and cause a strong impact electromagnetic force for the generator. With the traditional numerical calculation method, it is difficult to calculate the variations of key physical parameters and the electromagnetic field in the end region of the generator under complex working conditions, especially the out of phase synchronization fault. In order to solve the problem, a calculation method of the nonlinear transient electromagnetic field with multi-domain field-circuit-grid coupled is proposed. The correctness of the model and method is validated by comparing the calculated and test values of the magnetic density flux at the key points of the generator under the no-load condition. Based on this method, the power angle variation, the magnetic flux leakage distribution in the end region, and the electromagnetic force on the end winding in the transient process of the fault are calculated and analyzed. [ABSTRACT FROM AUTHOR]

This article proposes a calculation method for mechanical (electromagnetic) forces arising in an electromechanical energy converter acting on current circuits in a magnetic field, or on capacitor plates in an electric one. Transformations were performed on the basis of the principle of possible displacements involving the apparatus of partial derivatives. It was found that the power converted into mechanical power is partially spent on changing the energy of the electromagnetic field, and the remaining power, determined by the co-energy, is converted into mechanical power. Expressions for the mechanical (electromagnetic) forces were obtained based on the power balance. The reliability of the obtained results was compared with the known results. Of these, one can observe the well-known 50/50 principle, which states that only part of the power associated with the movement of the circuits is converted into mechanical power, while the rest is intended for changing the energy of the magnetic field. [ABSTRACT FROM AUTHOR]