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OHL Power Pointer

Funding mechanismNetwork Innovation Allowance (NIA)
DurationDec 2018 - May 2022
Estimated expenditure£1.302M
Research areaNetwork Improvements and System Operability
  • August 2021

    The first phase of PowerOn integration testing has been completed for Smart Navigator 2.0 sensors, with Fault Passage Indicator (FPI) features able to provid…


  1. Create policies for equipment installation and location;
  2. Carry out assessments of the accuracy and consistency of determining power flow directions within WPD’s distribution network;
  3. Provide recommendations on the number and location of devices needed for full visibility of power flowdirection;
  4. Quantify the savings gained by using the Smart Navigator to detect and communicate auto-recloser operations (rather than using visual inspections of AR equipment);
  5. Quantify the savings made to Customers Minutes Lost (CMLs) through the use of OHL directional FPIs;
  6. Provide the control room with visibility of overhead line real-time post-fault ratings.


Historically, it has been difficult to capture data in overhead networks, due to the construction of the system and the availability of equipment throughout the network to gather data. As Western Power Distribution (WPD) transitions from a DNO to a DSO, there is an increasing requirement for localised network monitoring to enable and enhance system operation functions. Moreover, improved monitoring could unlock latent capacity, hence leading to more efficient and economical utilisation of the assets.

The connection of Distributed Generation (DG), across all Distribution voltage levels has the potential to backfeed into faults. Currently in multi-branched radial or closed-ring networks it is very difficult to pinpoint the specific location of faults, while OHL fault locations tend to be currently identified via manual visual inspections.

Auto-recloser operations are also recorded manually via visual inspections. This is time-intensive for field staff that could be better deployed on other tasks. Moreover, due to operating temperature uncertainties and limited visibility, the control room currently only makes limited use of probabilistic post-fault OHL ratings, thus potentially underutilising the available circuits.


As the utilisation and requirements of the distribution network increase so too does the need for localised network monitoring. Historically, it has been difficult to capture data for the overhead network due to the construction of the system and the availability of equipment throughout the network to gather data. This project will trial a device that is capable of self-powering operation to provide real-time voltage, current and power flow information.

This information will be used to more accurately assess network operation, such as latent generation output and directional fault detection to more quickly identify the location of faults. Five business needs have been identified, all referenced within WPD’s Distribution System Operability Framework, which will be addressed by the following trials:

Method 1: Directional Power Flow Monitoring; 

Method 2: Directional Power Flow State Estimation (using directional monitors to infer power flow direction through non-directional sensors); 

Method 3: Detection of Auto-Recloser Operations (to assist with maintenance efficiency and short interruption quantification); 

Method 4: Directional fault detection (especially in 33kV networks with high levels of DG); and

Method 5: Conductor Temperature Monitoring (feeding into the post-fault rating of overhead lines).