| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a system which protects a bus bar in a short time without causing a large expense while protecting a secondary disaster at tentative charging after the occurrence of an earth fault. <P>SOLUTION: When the earth fault 11 occurs at a first secondary bus bar 5a, an earth fault overvoltage relay 12a connected to the first secondary bus bar 5a detects the earth fault, and when a bus bar communication blocker 8 is operated in order to tentatively charge the first secondary bus bar 5a from a second secondary bus bar 5b after a primary-side blocker 2a of a transformer 3a located above the first secondary bus bar 5a is operated, the earth fault overvoltage relay 12a arranged at the first or second secondary bus bar also detects the earth fault. The system comprises a control circuit 19 including a trip circuit for blocking the bus bar communication blocker 8 by using a first timer which operates when the detection time exceeds a prescribed time. <P>COPYRIGHT: (C)2008,JPO&INPIT |
