Features of the Decomposition of Graphitization Furnace Electric Circuit in Modeling AC Electromagnetic Fields

Аннотация

The existing methods for the calculation of electromagnetic processes in the system of current feeders in a graphitization furnace and of busbar packages in a furnace loop require making substantial assumptions, which significantly distort the real picture and do not meet modern accuracy requirements. The use of three-dimensional field modeling is restricted by the stability of computational processes, as well as by a significant expenditure of computational resources and time. In this paper, a numerical simulation of the conjugate spatial electric and magnetic fields in the area of furnace loop busbar packages, current feeders and the core of ac graphitization furnaces using a finite element method. A novel method has been developed for decomposition and dynamic synthesis of parameters according to the criterion for minimizing the current error to the calculate the electrical circuits of power supply systems for electric resistance furnaces with direct heating. The method provides a high accuracy in the calculation of active and inductive resistance and a decrease in active power and magnetic field energy according to the data of three-dimensional numerical-field simulation of complex systems for the furnace-loop busbar packages, current feeders, and core of a graphitization furnace. Criteria are determined for the decomposition of three-dimensional domains of ac conductor systems having a complicated spatial-and-geometric configuration in the subdomain. The application of the finite element method and the decomposition of the 3D domain of the furnace loop for a low-power ac graphitization furnace has provided a high accuracy and computational efficiency of the numerical implementation of three-dimensional electromagnetic field modeling. The relative errors of the method do not exceed 0.35% for the magnetic field energy, 1.45% for the electrical loss, 1.48% for the voltage drop modulus, and 0.67% for the voltage drop phases compared with the numerical values from field simulation of the furnace loop electric circuit. The proposed method can be used to calculate the parameters of electrical machines and short electrical grids characteristic of arc steel-smelting furnaces.