| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for management of the current transformer action which allows self-resetting without the intervention of an operator independently of power supply inputs and power supply system configuration. <P>SOLUTION: A primary object of this invention is to provide a method for managing the action of many current transformers which are arranged within respective groups and connected to protection relays forming a part of the three-phase power supply system. This method has the following steps: (i) measuring a current ratio at an output of each group of current transformers, (ii) comparing each current ratio with a predetermined high ratio; (iii) comparing each current ratio with a predetermined low ratio, and (iv) indicating a fault when the current ratio at other respective locations remains below the predetermined low ratio. Another object of this invention relates to a protection relay. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
