| 摘要 |
A current transformer of the top core type for high voltage application is formed by a column of insulating material supporting a metal housing including an insulating body through which the primary conductor of the transformer passes. A plurality of cores each including a secondary winding of the transformer are enclosed in a grounded metal casing and extend around the central portion of the insulating body to form annular regions between the metal core casing and the metal housing. The dimensions and weight of the top part of the transformer are reduced by utilizing insulated metal rings provided for obtaining a uniform voltage distribution in the annular regions between the core casing and the housing. The insulated metal rings consist of metal foil between plates of insulating material and may completely fill the annular regions. The core casing includes planar end pieces abutting the insulated metal rings. A barrier of solid insulating material may be wound around the metal core casing and the insulated metal rings. The insulated column may include a voltage-controlling capacitor bushing with a grounded tube forming the passageway for the secondary winding conductors. Second insulated metal rings may be arranged in a region around the upper part of the voltage-controlling capacitor bushing for voltage control between the metal core casing and the housing. |
