| 摘要 |
The invention deals with an HV voltage coil which is an element of a voltage transformer used in a combined instrument transformer applicable in high voltage electric power measuring systems. The voltage coil comprises a magnetic core (16), a primary winding (13) wound onto a secondary winding (14) and surrounded by an upper screen (17), a bushing of a high voltage instrument transformer in the form of a conducting rod (21) placed in insulating material (23) with equipotential screens (25), the primary winding together with the upper screen being located in the coil insulation (24) which is covered by an external screen (26). The voltage coil according to the invention is characterized in that the upper screen (17) has the shape of a ring with a gap (18), which is integrated with a connecting element (19) in the form of a truncated cone. This base of the cone which has the larger diameter is situated on the external surface of the ring, and the cone has an axial opening (20) into which a threaded end of the conducting rod (21) is screwed. Equipotential screens (25) are situated centrically around the rod (21) and they have overlapping longitudinal edges which do not touch one another in any point. A copper tape (27) is wound on the insulation (23) and on the external screen (26) of the voltage coil. |
