| 摘要 |
<p>The branching unit is for use in a submarine telecommunications cable system which employs electrical power feeding for repeaters/regenerators of an optical fibre cable system, and in particular a system employing multiple branching units. The unit terminates three line cables (at 1, 2, 3) and a sea earth (at 4) and includes three high voltage relays A, A1, B, B1, C, C1, only one of which is energised at a time. When electrical power is supplied between any two line cables e.g. 1 and 3, an associated relay coil, e.g. C, is energised so that its contacts C1 isolate the third 2 and connect it to the sea earth 4. Short circuit or open circuit faults in one line cable may be isolated and connected to the sea earth, whilst allowing powering of the remaining fault free two line cables. The unit is polarity insensitive and symmetrical, cathodic protection being provided on all three lines. <IMAGE></p> |
