WITT WB CM 7 Copper Cable Monitoring

Description

Copper cables, and in particular return-line reinforcement on DC railways (single-core cable 1 x 500 mm²), not only fulfil an important function within the system, but are also highly attractive due to the value of the copper they contain. Consequently, thefts are unfortunately not uncommon and result in losses many times greater than the material value of the stolen cables. Furthermore, high costs are incurred for repairs and potential train cancellations. Added to this is the fact that faulty return conductor systems can lead to dangerous contact voltages, thereby posing a risk to people and equipment.
We have developed the WITT WB CM 7 modules to enable reliable monitoring against theft, as well as the detection and localisation of tampering with copper cable systems.

• Detects even the simplest attempts at tampering, e.g. a short circuit in the monitored cable.
• Reliable real-time detection of cable damage or tampering.
• Detects cable damage caused by civil engineering works.
• Detects water ingress in the cable or its sheathing.
• Any interruptions to the cable caused, for example, by theft or civil engineering works.
• Determines the point of fault with an accuracy of approximately 2–5 per cent. Example: For a 3 km-long cable, the fault location is pinpointed to within 60 to 150 metres.
• Enables immediate preventative or maintenance measures and avoids unnecessary downtime.

Detection of damage, e.g. to Nexon’s RHEYRAIL cable, protection against theft and detection of tampering with a view to cable theft.
Any alterations to the cable, insofar as they affect the monitoring wires, are immediately detected and reported. In the event of a fault, the location is determined either by measuring the resistance or the capacitance. The following alterations to the cable trigger an alarm:

• Cutting the cable without causing a short circuit between the monitoring wires and the inner conductor results in a lower capacitance between the monitoring wire and the inner conductor, so that the resulting distance is calculated and displayed using a stored reference value
• Cutting the cable, resulting in a short circuit between the monitoring wire and the inner conductor, leads to a lower resistance in the monitoring wire, so that the resulting distance is calculated using a specified reference value and displayed.
• Bypassing a monitoring lead.
• Liquids entering the cabling
• If several cables are to be monitored using a single device, the inner conductors of the cables must be at the same potential.