Transmission line fault locating system - regulates current through test voltage transmitting diode so that each repeater before line fault receives same current contribution

摘要

Communication transmission line faults are located using series-connected DC supplied automatic repeaters. In the terminal exchange a test voltage source has opposite polarity to the remote supply circuit by means of an indicator. A cross-branch in each intermediate repeater is positioned between the repeaters of the two transmission directions. It transmits only the test voltage via a suitably poled diode. The cross branches, which are switched on by switching on the test voltage source (Uo) comprises constant current circuits (K1, K2, to Kn) in series with the diode (D1, D2 to Dn). The current regulating range is arranged so that the cross-branches supply the same constant current contribution to all repeaters immediately before a fault.