Hi-5
| Funding mechanism | Network Innovation Allowance (NIA) |
|---|---|
| Duration | Jun 2025 - Oct 2029 |
| Estimated expenditure | £2.231 million |
| Research area | Research area Net zero and the energy system transition |
Our existing HV cable assets are aging over time, and future demand from consumers is predicted to increase as they transition to low carbon technologies. There is a need to optimise investment planning, balancing asset health interventions and asset reinforcement, that minimises the impact to consumers through Customer Interruptions (CI)/Customer Minutes Lost (CML).
The Hi-5 project is looking to understand the time to failure indicators on our HV cable assets through the installation of low-cost monitors. This insight will be used to support changes to our cable health methodologies, and therefore our future asset investment needs.
Problem(s)
At present, underground High Voltage (HV) network investment quantification methodologies in Electricity Distribution planning allow for load-related capital expenditure but not non-load (i.e., fault/age related). Unlike other network assets, underground (UG) HV networks are not included within the Common Network Asset Indices Methodologies (CNAIM) (with the exception of fluid filled and submarine cables).
The Energy Networks Association (ENA) industry group have previously explored expansion of CNAIM to include cable types, however, they were unsuccessful due to the lagging nature of available measurable outputs (historical fault data).
Method(s)
Hi-5 will undertake a 4.5-year longitudinal study of HV UG networks to provide a methodology that captures all aspects of underground network health. Monitoring equipment and data analysis will identify network indicators that will provide an insight to probability and time scales associated with “time to failure”. This new data driven approach will be the key insight to unlocking an effective sustainable underground network reinforcement methodology improving UG HV network resilience.
The outcomes of Hi-5 are vital for all customers, with the uptake of Low Carbon Technologies (LCT)s e.g. increased electrified heating, society will be ever more reliant on electricity and dependent on network reliability. This could be exacerbated in the longer term as UG network asset life related health issues may increase at the time that demand for electricity is at its highest.
Scope
Hi-5 aims to provide a new approach to provide data to expand learning around ‘leading' indicators of emerging underground network health issues rather than historic problematic 'lagging' fault history data. By identifying time to failure of UG networks we aim to provide a data informed approach to cable replacement avoiding unnecessary expenditure, supporting ahead of need network reinforcement to adopt a one touch approach that considers both load/non load UG network replacement and network reliability improvements.
The need to be proactive in the identification of faults will increase as more customers adopt low carbon technologies as part of the road to Net Zero. Net Zero is a strategically important outcome for GB, National Grid, all DNO’s and customers brought into focus through the Clean Power 2030 report by the National Energy System Operator (NESO). The challenge is huge and requires fundamental change in industry approach. As a DNO, NGED is aware that addressing/locating sections of suboptimal network and optimising replacement of HV UG networks will be critical to supporting the road to net zero.
Analysis undertaken shows that at the time when demand is expected to be at its highest it also coincides with the highest volumes of underground cables reaching the end of their serviceable lives. In reality the service life of a UG HV cable can significantly vary, an aging cable is not necessarily at a greater risk of failure, however, there is currently no method to quantify this. UG networks can fail prior to their suggest cable service life with many networks remaining in service well past their recommended cable service life.
A significant proportion of UG HV network faults are not directly related to cable failure or age, rather being caused by other variable such as deterioration of cable joints / terminations, environmental conditions and historic installation techniques/materials.
There is risk that relacing cables on a purely age-based consideration there may be minimal impact on improving network reliability and overall value for customers. Monitoring the health of underground networks will support areas where condition-based replacement would be beneficial to both support load growth and improve network reliability whilst allowing an informed approach to deferring the replacement of aging cables.
At present, current regulations do not allow for the flattening of the future peak volume curve, as investment is only sanctioned and funded for the next price control. To ensure the correct cables are replaced ahead of peak demands and to smooth the cable replacement workload over time, then informed proactive network reinforcement will be required.
The project is seeking to find a solution by altering the forecasted replacement curve to ensure work is undertaken at best value to consumers. Hi-5 will support the one touch approach to cable replacement/reinforcement providing the most timely, cost-effective way of combining network reliability improvements (reduction of faults) with network capacity growth. By investing ahead of need, targeting poor health networks and deferring reinforcement, future work volumes will be sustainable for future years whilst continue to achieve the road to NetZero. The project aims to gather the evidence needed to improve industry understanding of UG network health to support the flattening of UG load/non-load (currently cable age) replacement curves before the peak demand is reached.