| 摘要 |
of the disclosure 1. Current transformer 2.1. The object is to provide a current transformer which can be installed in a grounded metal casing surrounding a high voltage conductor, having an annular core and a secondary winding surrounding the annular core in a toroidal configuration, in which the current transformer is to be protected by means of structurally simple measures against overvoltages at the secondary winding due to switching operations. 2.2. In addition to the secondary winding (5) of the current transformer (2) there is provided a further winding (9), which is conductively connected at one end to ground potential. The secondary winding (5) is screened by the further winding (9). Moreover, as a result of the grounded further winding (9), the total capacitance between the secondary winding (5) and the metal casing (1) is increased. The capacitance conditions of the capacitive voltage divider formed by the high voltage conductor (3), the secondary winding (5) and the metal casing (1) are designed thereby so that the secondary winding (5) is protected against overvoltages due to switching operations. 2.3. The invention can be used in current transformers for encased switchboard plants. 3. FIG 2
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