Process steps & methods: Pre-location
The objective of pre-location is to determine the fault position as precisely as possible so that the subsequent pin-pointing activities can be implemented as quickly and efficiently as possible.
Secondary/multiple impulse method in DC mode for pin-pointing intermittent faults. DC voltage is applied to the cable until breakdown. The cable capacitance is used to increase the available surge energy.
Difficult to locate or wet faults are first conditioned with surge voltage before a SIM/MIM measurement is carried out.
Impulse current method used in DC mode for locating chargeable breakdown faults for which the cable capacitance is used in conjunction with a surge voltage generator.
Measurement mode with envelope curve display
In this process, even small, intermittent changes to impedance can be made visible by means of an envelope curve and saved automatically.
Fault conditioning / burning
High-resistive cable faults are handled with high performance high voltage burn down transformers. The ensuing fault becomes low resistive and therefore can be easily measured according to the TDR method. This application is used for the conventional paper-lead-sheath cables.