Analysis of Electromagnetic Influences Concerning Two Adjacent Parallel High-current Bus Ducts

摘要

Due to the medium-voltage level of generator terminals and very high current output, generator connection to the step-up transformer is often accomplished by means of high-current air-insulated bus duct systems. These high currents during normal generator operation produce accompanying power losses, which could result in excessive heating of the bus duct system. Additionally, the associated electromagnetic fields could have adverse effects on the performance of the neighboring equipment. Problems are further exacerbated by the fact that there are often two parallel adjacent systems, often equal in cross-sectional geometry, which interact through the electromagnetic coupling. The starting point for the analysis of the aforementioned problems involves a determination of current distribution in phase conductors and in the shields of the metal-enclosed bus duct systems. This article presents a computation model for the mentioned analysis, which is based on the mesh-current method, with the application of the geometric mean distance method in combination with the conductor filament method. It takes into account both skin effect and proximity effects, as well as the complete electromagnetic coupling between phase conductors and metal enclosures of two mutually parallel and adjacent high-current bus duct systems having equal cross-sectional geometry.