Ground fault tracing: AC tracing vs pulse tracing

When searching for ground faults, a transmitter injects a current through the fault (fault current) and a receiver is then used to trace the path of the fault current. The injected current can be either an AC signal or it can be a pulsed DC output. A pulsed output often needs to be synchronised with the receiver. This way the receiver knows when to look for the pulse. This is required due to potential noise on the system. Random noise can look like a pulse. However, on very noisy systems this can still be problematic. In addition, if the sync is lost, then the receiver needs to be reconnected to the transmitter in order to acquire the synchronisation again. Capacitance can also be a large problem for pulsed outputs. There will always be some amount of capacitance on a DC system. Shielded cables have a capacitive property. They consist of 2 conductors separated by an insulator. This is, in essence, a capacitor.