Electrical valve measurer for pin-pointing transients - detects resistance alterations in earth symmetrical or coaxial double cores or voltage drops at appliances

摘要

Appliances, remotely fed by a constant current, esp. those used for data communication, are integrated in cable systems. At a floating potential, the earth symmetrical or coaxial double core cable, with short time resistance differences (DELTA R (DELTA t)), at the end is looped back via a further current path, as a measurement current path of the same cable. Upon detection of a possible fault in the outer conductor, a remote fed measurement switch (MFSpW) at a floating potential, isolates the ohmic connection of the two outer conductors at the measurement point. The remote feed adaptor (Fsp adaptor) is replaced by a measurement remote feed adaptor (MFsp adaptor) upon occurrence of a resistance-voltage jump in the longitudinal branch of the inner and outer conductor. After fault location, a capacitive voltage divider is made effective between the inner and outer conductors in relation to the fault location, by the capacitive coupling of the measurement loop start (A) across the fault location (X), the far end (B,B') and back (A'). The resistance-voltage jump is distributed reciprocally proportional to the capacitance ratio, and is supplied to the recording measuring unit via isolating capacitors (Cka,b). ADVANTAGE - At non-foreseeable time, occurring resistance differences or jumps, with or without remote feed, are located exactly. Allows automatic measurement.