Many faults on the low voltage (LV) network are caused by gradual degradation of underground feeder cables. As the cables age/insulation layers gradually break down allowing the ingress of moisture, which starts to cause momentary short circuits between the conductors. This causes an arc which often vaporises the water and clears the fault. These faults are known as ‘transient faults’, and they are invisible to the DNOs and customers. As the cables degrade further the arc current may be sufficient to cause a fuse to blow, causing a power cut. If the fuse is replaced, the fault will appear to have cleared. However, the underlying fault will remain, meaning that the fuse will blow again, giving rise to an ‘intermittent fault’. Eventually fuse replacement will not clear the fault and the fault becomes permanent.

Current DNO practice is mostly reactive, with faults only becoming visible when they are reported by customers. Standard practice is then to replace the fuse, if the fault is not cleared then technologies such as Time Domain Reflectometry (TDR) are employed to locate the fault. These faults account for a significant proportion of LV network costs and Customer Minutes Lost (CML).  To technically and economically improve the performance of the LV network, there is a requirement to move from reactive to proactive management of LV faults.

Objectives

Stage 1 Objectives – SYNAPS Technology Validation at Power Networks Demonstration Centre (PNDC) (TRL5)
 
•  Demonstrate a two-unit SYNAPS system
•  Test SYNAPS technology at PNDC
•  Validate technology and prove it can detect, classify and locate faults to required level of performance
• Collect and analyse data to facilitate improvements in algorithms
• Collect and analyse data to facilitate future improvement of LV network simulation model
• Preparation for Stage 2

Stage 2 Objectives – Demonstration of SYNAPS operation in a working environment on UKPN network (TRL6)

• Enhance SYNAPS algorithms and demonstration system based on PNDC report
• Understand network interface/connection requirements
• Two pairs of sensors will be delivered to the participating DNOs (one set for UK Power Networks & one set for SSEN) for operation on actual LV network
• Design concept and specification for link box/substation sensor (including transducer)
• Document the cable calibration procedure
• Enhancement of LV network simulation model to include cable calibration
• Demonstration of prototype SYNAPS sensors on feeder(s) chosen jointly with UK Power Networks and SSEN (detection, classification and location of faults on feeders with known issues) installation for duration of demonstration only and supported by personnel from the manufacturer and the DNOs.
   -Incudes detailed site surveys to establish optimal locations for prototype SYNAPS system
   -Deployment of prototype SYNAPS system on problematic feeders with known faults
    -SYNAPS will be used in conjunction with traditional fault location instruments, such as TDR and cable sniffers, in order to validate location results when faults become permanent