| 摘要 |
<p>A module for insertion into a combined signal and power carrying line, especially into a CATV line, for protecting a system associated with the line from an overcurrent comprises: (i) a housing (50) having connection ports (51, 52) for cables (53, 54) forming the line and being impedance matched to the line, one of the conductors of the cables being connected together via a capacitor (23); and (ii) a solid-state overcurrent protection circuit that is connected across the capacitor via inductors (24, 25) to isolate it from the signal on the line, the protection circuit being capable of switching from a conducting to a blocking state in response to an overcurrent and being capable of resetting itself or attempting to reset itself into its conducting state one or more times after it has switched into its blocking state. If line containing a number of such modules is subjected to an overcurrent, the protection device in the nearest module upstream will switch so that only that part of the line downstream of the module will be affected. In addition, tracing the location of the fault is much simpler because the section of the line in which the fault occurred is known from the protection circuit that has tripped.</p> |
