Underground power cable fault identification system as a cable theft deterrent

Good day,

I am seeking a Underground Cable Monitoring system capable of the following:

  • Cable fault identification through GPS and GSM(Cellular) techniques
  • Linkable to SCADA system to enable Control Center alert

In short, we are overwhelmed by a series of Underground Cable theft and we need a solution to guard against this. Please share your experiences on this and solutions.

  • What sort of cables are we talking about? Power, data, signalling?

    Are you wishing to prevent theft, or merely detect when it happens?

    I know that Network Rail have adopted a number of techniques - often starting with relatively low tech solutions - like using expanding foam to make cables difficult to remove from lineside ducts. Why the preference for GPS/GSM? Depending on the cable usage, I would have thought that a quite wide range of techniques might possibly be useful - from simple end-of-line resistors to TDR to calculate the distance to a break, with relatively simple GIS being able to translate the distance or circuit layout into a geographical position.

        - Andy.

  • The reason for GPS is that we currently are using ARCGIS system and have a Maintenance/Operations team that needs communications. Each time there is an incident of cable theft they arrive late and are not able to get quickly to the point of theft.

    This system will be also shared with security personnel to ensure that the culprits are caught.

    Faults are identified manually with existing GPS system. For Protection Relay using TDR (Time Domain Reflectometer) we are able to determine distance to fault but we have not yet integrated the Protection System to the GPS system. Therefore, we do it manually at the moment.

    We are currently open to other alternatives even adding it to our current VHF, UHF or any other radio system.

  • Had you considered using a numerical Distance Relay? If these are correctly configured with the cable impedance (and that may be a problem if you have varying conductor sizes throughout the route), then the relay should give you a fairly good "Distance to Fault" in the event of a circuit trip. If the relay also has a "SCADA Interface" built in, then I would expect that "Distance to Fault" was one of the parameters that could be read, for onward transmission to the Control Room. To improve accuracy, if you can get the figure from both ends of the line, you should be able to come up with some sort of average distance calculation. You should know the total length from either installation records, or from your mapping system to help with the calculation. 

    The other option, which will be more accurate, but probably more difficult to achieve would be an on-line distance measurement of the line using some kind of travelling wave injection. 

    Regards, Alan. 

  • Thanks for your response Alan.

    The problem I have is that not all feeders are able to have Protection Relays. Some just have Auto Reclosin. And there are some not on SCADA.

    Those that are on SCADA give the Control Centre monitoring through loss of a feeder cable. 

  • It seems to me that underground cable theft is a major undertaking requiring access, diggers, secluded places. If this is happening at specific locations, e.g. where the underground cable is not underground, then a better approach might be to monitor these locations so the attempted theft can be identified before the cable is cut and removed.

  • I suspect that cables are fished from ducts by gaining access at unlocked manholes and so on, rather than digging up a trench along the cable route.
    It is not easy to lock such a network  down, as then your own folk all need a key to each manhole, cabinet  or whatever and at some point one will be lost, and then you have to replace the lot, and even if that is not an issue remote locks can freeze or be jammed.
    Procedural changes to the installation such as cable clamps, so the thieves hoping to pull a valuable length quickly, only remove a short piece can be phased in over time but non of that is easy.

    Mike.

  • Hi Russel, I used to work for a company called Fotech Solutions. They provide monitoring systems that can identify any number of intrusion or failure events using a fibre optic cable located along the length of the asset. For instance, they had thousands of kms of pipelines being monitored and could detect people walking or digging near the pipeline. The system could detect an event down to a few meters and report this through a number of interfaces including SCADA. They also had systems monitoring border fences, power cables and many other applications. Might be worth a look to see if this could be a solution for you. https://www.fotech.com/

  • Thanks for your response David. Very much appreciated. I will look into it. Please be open for further enquiries