SYSTEM FOR FINDING FAULT IN OPTICAL SUBMARINE CABLE

摘要

PURPOSE:To improve the accuracy of the fault finding effected by a DC resistance measurement performed when a fault such as disconnection of the cable or the like is occurred, by utilizing the cable structure. CONSTITUTION:Because a cable 32 has at least two kinds of metal portions which are insulated from each other, one of them is used as a feeder line, while the other is used as a resistance measuring line 35. The DC resistances for respective spans are to be Rl1 between a terminal station A and a m1 repeater, Rl2 between the m1 and m2 repeaters, and Rlmalpha1 between the mm-1 and mm+alpha repeaters, and supporsed to concentrate on respective repeater parts 31. In this case, when there is a fault in the mm+1 span, the DC resistance measured from the side of the terminal station A is shown by the formula I. The ratio of the differences in the resistance values between the case where there is a fault in the repeating span adjacent thereto is shown by the formula II. If Rl1Rl2...Rlm, FR1mm is established at arbitrary mm. Properly setting m1, m2..., Rl1, Rl2... permits FR to be set so as to be two or three times of 1/mm.