High Voltage Feeder Monitoring to Pre-empt Faults

Faults on the network can cause Customer Interruptions (CIs) and Customer Minutes Lost (CML) leading to penalties from Ofgem and complaints from irritated customers. The Network Innovation Allowance (NIA) project “11kV Feeder Monitoring and Pre-empt Faults” aims to test the functionality of Distributed Fault Anticipation (DFA) and other network monitoring equipment such as Fault Passage Indicators (FPIs), which pre-empt faults and prevent the outcome of faults leading to CI and CML.

The project is in three stages, with the first stage trialling the DFA and FPIs at the PNDC through a series of simulated faults that were designed to be highly realistic of those on actual distribution networks. Following successful trials in US and Australia, this was the first time the DFA technology had been demonstrated in the UK.



Hosting the trials at the PNDC during stage one led to recommendations for the Distribution Network Operators (DNOs) to take into consideration when they progress to stages two and three, trialling the equipment on live distribution networks.

The PNDC recommended allocating a data allowance for each device per month as well as DNO trial circuits being selected based on a history of relevant events and the selected circuits should ideally be heavily loaded and located in an area with prevailing wet and windy weather conditions.

These recommendations could not be taken into consideration or implemented in stage two and three without prior testing on a simulated network away from DNO customers, which would have the potential to affect the overall results of the project as well as customer interruptions and minutes lost.




It is anticipated that the deployment of 60 DFA devices across UKPN and SSEN (30 per DNO) will deliver £853,500 in gross annual savings. This assumes the pre-empting of eight faults per year by the undertaking of proactive maintenance, enabled by the DFA solution. This also assumes that proactive repairs are at least 40% cheaper than reactive fault repairs within the DNO network.

Through cost-benefit analysis (CBA) a net benefit of £1.6m net benefit during RIIO-ED1 has been calculated. The test programme delivered by the PNDC will support UKPN, SSEN, and SPEN in realising this benefit much sooner within the current regulatory price control period. All three DNOs will also be able to claim quality of service benefits through outperforming against their Ofgem CI and CML targets.

PNDC provides excellent test facilities and expertise to assess solutions for use on electricity distribution networks. UK Power Networks has used PNDC’s services to test a number of network equipment and applications. In my experience, their work has been completed in accordance with requirements, on time and within budget. Use of the test facilities and expertise at the PNDC was essential in determining the suitability of the proposed solutions before application on the distribution network. The alternative would have been a limited deployment of solutions on the network leading to longer business as usual rollout.

Chino Atako

What’s next?

Stage two of the project is now underway, which consists of live network trials within UKPN and SSEN (total of 22 DFA devices). These trials will look to develop and test operational process and practicalities in implementing the devices within a customer connected network.

This stage will last for initially six months and then through to the duration of the project if extended network trials (Stage three) are permitted.

Through this approach it is expected that process-level integration within UK distribution system can be achieved, with DNOs able to gain operational experience in trying to pre-empt faults.


More ‘eyes’ on the network to stop power cuts before they happen
Futuristic technology designed to prevent power cuts is being trialled by UK Power Networks.
Press release, February 2021, UK Power Networks.

Key stakeholders:

SPEN logoSSEN logoUKPN logo


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