MULTI-LAYER MAGNETICALLY SHIELDED ROOM FOR HIGH CURRENT INJECTION SYSTEM

摘要

Since high current transformers are within the major group of the standard type, test equipments in electrical industry, their performances are very important. When designing a high current device, there are many factors, which the compatibility of these devices with the internal and external propagation and generation of low frequency and high frequency disturbances within electromagnetic environment must be ensured. Up to the present time, as far as the authors are aware no report on shielding structures for high current systems in low frequency has been made. This paper attempts to fill this void in our knowledge by considering various issues related to shielding design consideration in a 25kA current injection transformer (CIT) as a high current system, using 3D electromagnetic fields (EMFs) simulation tools to calculate shielding effectiveness of multi layer shields in low frequency. As matter of comparison of finite element method (FEM) simulations to measurements, a short circuit test was carried out on a typical CIT. This paper also reports the propagated and the generated low frequency near fields around the CIT and shielding effectiveness of multi layer shields against these radiated fields.