| 摘要 |
<p>PURPOSE:To improve the transient characteristic of current transformer by detecting the DC flux in the core then cancelling said DC flux. CONSTITUTION:A air gap is provided in the core of current transformer 1 and the fulx detector 3 for detecting the DC flux is provided in it. Furthermore secondary winding 2 and compensating winding 4 are wound around the core 1. The signal from the detector is amplified by the amplifier 6 then the polarity is decided at the polarity decider 7. Then the output from DC current controller 9 is controlled by phase control circuit 8. The output from said controller 9 is supplied through high impedance element 10 to the compensating winding 4. The DC flux in the core 1 is cancelled by the current in said compensating winding 4. Consequently the trasient saturation of the core is eliminated thereby the cross-section of the core is reduced and the transient characteristic is improved.</p> |
