| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of zero-phase current transformers and ground directional relays which protect two circuits of a loop, particularly a normally- open loop, in which distribution substations are connected, and are necessary, because if the distribution substation on one circuit side has a ground failure, it is cut off and a power is supplied from the other circuit and hence both the circuits are to be protected from the ground. SOLUTION: An input side high-voltage main line 1 and an output side high- voltage main line 2 are made to penetrate together a core window of one zero- phase current transformer 4, the secondary output of the zero-phase current transformer is detected by a ground detection protection means 5, and a switch 1a and a switch 2a are opened simultaneously, if the ground failure is within a protection region only.
|
