Project Summary
Electrical grid owners regularly perform complex repairs and maintenance tasks to make sure the network is reliable. However, many of the complex operations require outages, and this can put a pressure on the rest of the electrical networkand its future development. Live Line working can relieve this pressure, however electrical infrastructure is currently not built with Live Line working in mind, thus making it hard to deploy this service in most locations. Project DELLTA will look to understand if HV assets and infrastructure can be designed with Live Line workingas a key parameter from the outset.
Innovation Justification
Project DELLTA primarily addresses "Innovation Challenge 1: Faster network development", by facilitating faster connection, upgrades, maintenance and replacement of assets.
The project is of particular relevance to TOs within GB, and could offer benefits to GB electricity consumers, and is therefore within the remit of SIF funding.
The project seeks to develop novel designs and tooling approaches to facilitate live working. This may involve fundamental changes to legacy asset and infrastructure designs. For example, rethinking how substation designs can be changed to enable Live Line working, rather than retrospectively fitting live line work around legacy designs that inherently inhibit live line work. We will consider solutions with various technology and integration readiness levels, and would also seek to leverage innovations from other sectors, such as the use of robotics innuclear environments, to consider more live line and robotic inclusive designs.
The project is not designed to develop live line processes and policy (which is BaU for work involving human staff as opposed to autonomous systems, at present the justification process limits where live line working can be utilised). Instead, it is to rethink how we design the electrical infrastructure to enable Live Line working with better efficiency. This distinguishes it from BaU activities.
There are currently no requirements to include Live Line Working within asset or system design. Whilst there are policies and working procedures for Live Line working itself, this does drive design of the assets that need to be maintained. Some projects that have focused on line compaction have actually resulted inincreased challenges in respect of live line work. This is where this project will differ from previous projects within the Live Line Work (which have been towards the policies and processes).
While there are already established standards for ensuring the safety of human workers, DELLTA will explore whether the design of HV assets (for example, towers) could be adapted to better accommodate live line work, improving efficiency without compromising safety. It will also identify opportunities for new internal standards / technical specifications for activities that may be executed autonomously, and understanding the associated risk with such an approach (risk of causing an unplanned outage resulting in the need to grid balancing on thelocal system).
Impacts and Benefits
HV assets and infrastructure are not currently built to easily enable live line work, therefore Live line work is limited on GB transmission networks, and most maintenance is done via planned outages.
Network outages can lead to an increase in constraint costs. In 2018, NGET reported that from that around annual 8,000 planned outages, approximately 15% caused network constraints with an annual cost of £220m. Since then, the average cost of relieving constraints has risen from around £109/MWh to £215/MWh across 2023, implying that equivalent outage related constraint costs today would be in the order of £434m. As network utilisation increases, it is likely the volume of constraints and associated cost will also increase. Live line working could reduce constraint costs and offer significant value to the customer.
More broadly, outages are difficult to schedule and in some cases maintenance projects can see late postponements due to network availability. This can leave assets more vulnerable, increasing risks of failure and unplanned outages, and can reduce operational life.
Potential benefits
The aim of this project is to consider live line maintenance at the design and planning stage to enable safe and efficient live line working. This could offer various benefits including:
Targeted design changes to critical transmission corridors, purposefully built for live line access and maintenance, increasing system resilience
Faster and more efficient connection and maintenance.
Reducing network outages -- with associated network constraint cost reduction.
Better and more flexible network maintenance planning -- with subsequentbenefits for asset health, lifespan and reliability, with fewer post ponements of scheduled maintenance
Improve safety for critical live line maintenance activities.
We will develop a methodology for calculating benefits in Discovery. It will be developed with reference to Ofgem's SIF CBA Template. Project specific benefitswill include:
Financial - future reductions in the cost of operating the network
Reduced system operability costs -- relative to a counterfactual where network outages cause constraints and incur balancing costs.
Reduced maintenance costs through more efficient work planning and delivery, and reduced postponements.
Reduction in curtailment of low carbon generation.
New to market -- products and services
The project aims to identify new designs and tooling options which could be developed and employed on future networks. For the Discovery Phase, we anticipate being able to report financial benefits on a ROM basis, with a moregranular estimation of overall benefits and costs expected in later phases.
