Численные расчеты магнитных полей в торцевой зоне турбогенераторов

Abstract

Проведен обзорный анализ, показаны принципы и примеры численных расчетов магнитных полей в торцевой зоне design modelsтурбогенераторов. Приводятся основные положения разработанных методов, основанных на плоско-меридианной и плоско-ортогональной расчетных моделях. Они сочетают взаимосвязанные магнитные поля в поперечном и продольном сечениях электрических машин. При расчетах учитываются реалистичная геометрическая структура активных элементов концевых частей и насыщение сердечников этих машин и турбогенераторов в частности.

Calculations of magnetic fields in the end zone (EZ) are topical for turbo generators of limiting capacities. Eddy currents and additional power losses in the design elements reach critical values because of their high heating in such generators. An overview of the previous authors' achievements on this problem is realized. The principles and examples of numerical calculations of magnetic fields in the turbo generators end zone are shown. The main provisions of the developed methods are given. They are based on a flat-planemeridian and orthogonal design models. Formation of adequate magnetic fields in the EZ is provided by the complex of boundary conditions for the magnetic vector potential. The calculations take into account both the magnetic field displaced from the active parts of the machine and the action of the frontal part of its windings. Flat-orthogonal design model is based on interrelated calculations of magnetic fields in the transverse and longitudinal sections of the turbine generator. Therefore, this model can be attributed to a quasi three-dimensional. It is competitive to a three-dimensional model and provides results adequate to physical concepts about this kind of fields and the available experimental data. The calculations take into account realistic geometric structure of the active elements of the end portions and the saturation of turbine generators core. Modes of magnetic fields excitation in the EZ and influencing factors are determined. Particular attention is paid to the calculation of the magnetic field in the load-condition mode with the simultaneous action of the rotor and stator windings. Such calculations are much more complicated than the separate action of these windings. Results of the magnetic fields calculation in the turbine generators end zone are used for the calculation of eddy currents and additional power losses in the stator core end and other design elements. They are also the basis for the study of force in the EZ, inductive parameters of the windings coil ends and other electromagnetic parameters of turbo generators.