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This paper presents a mathematical description of the electromechanical energy converters with permanent magnets. Unlike well-known mathematical models the mathematical description is obtained by the joint solution of Maxwell and Fourier equations. This allows to determine the geometric dimensions of the active part of electromechanical energy converters taking into account thermal and electromagnetic processes on the stage of the design calculations. Finite element method is used for the final calculations of the full geometry of electromechanical energy converters. Computer simulation and experimental study of electric machines with high-coercivity permanent magnets were investigated to evaluate the effectiveness of the obtained results. The results of experimental studies have been compared with mathematical model and its high accuracy was obtained. [ABSTRACT FROM AUTHOR]

This paper proposes a set of mathematical models presenting magnetic fields caused by operations of an extra high voltage (EHV) transmission line under normal loading and short-circuit conditions. The mathematical models are expressed in second-order partial differential equations derived by analyzing magnetic field distribution around a 500-kV power transmission line. Finite element methods (FEM) for solving wave equations have been exploited. The modification for complex magnetic field analysis and time-harmonic simulation are also utilized. The computer simulation based on the use of the FEM has been developed in MATLAB programming environment. The problem of study is intentionally two-dimensional due to the property of long line field distribution. To verify its use, i) single-circuit and ii) double-circuit, 500-kV power transmission lines have been employed for test. From all test cases, the calculation line of 1.0 m above the ground level is set to investigate the magnetic fields acting on a human in comparative with ICNIRP standard. Moreover, visualization of magnetic fields caused by fault currents flowing through EHV transmission lines is included. [ABSTRACT FROM AUTHOR]