| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent failures etc. in equipment by allowing for operation to continue even when CT saturation occurs due to an internal accident. <P>SOLUTION: A ratio differential characteristics determination unit 14, which determines operation of ratio differential characteristics based on an operation amount Id and a restraint amount Ir, includes a first current region determination unit 14-1 which determines that operation has taken place when Id>a<SB POS="POST">1</SB>Ir+b<SB POS="POST">1</SB>holds while, with regard to real numbers a<SB POS="POST">1</SB>, a<SB POS="POST">2</SB>, b<SB POS="POST">1</SB>and b<SB POS="POST">2</SB>, a relationship a<SB POS="POST">1</SB>≤a<SB POS="POST">2</SB>, b<SB POS="POST">1</SB>≥b<SB POS="POST">2</SB>applies, a second current region determination unit 14-2 which determines that operation has taken place when Id>a<SB POS="POST">2</SB>Ir+b<SB POS="POST">2</SB>holds, and a group of an AND arithmetic unit 14-3, a reset unit 14-4 and a flip-flop unit 14-5 which, when operation has taken place in both the first and the second current regions, determines that operation of ratio differential characteristics has taken place and allows operation to continue until operation in the first region is reset. <P>COPYRIGHT: (C)2012,JPO&INPIT |
