| 摘要 |
A current transformer for a metal-encapsulated, gas-insulated switching installation has current transformer cores (10) which are arranged in metal encapsulation (2) (which is designed to be essentially rotationally symmetrical) and surround an inner conductor (1) which carries high voltage. An earthed, tubular screen (8) is provided between the current transformer cores (10) and the inner conductor (1). This current transformer is always intended to produce reliable measurements of the operating current, which is passed through the inner conductor (1), of the switching installation, even during switching operations which are linked to the occurrence of travelling waves with steep voltage rises. This is achieved in that the screen (8) and metal encapsulation (2) are electrically conductively connected to one another in such a manner that only a portion, which is required for charging the capacitance formed by the screen (8) and the inner conductor (1), of a current, which flows during the propagation of the travelling wave on the metal encapsulation (2), is supplied to the screen (8), and in such a manner that, furthermore, the inner surface of the metal encapsulation (2) in the region of the current transformer cores (10) is virtually free of material recesses and projections. These measures make it possible for the high-frequency current which is linked to the travelling wave to pass through the current transformer without any disturbances and at the same time reliably prevents overvoltages occurring on the screen (8), with respect to the metal encapsulation (2). <IMAGE> |
