This article originally appeared in the September 2021 newsletter of the International Federation of Operational Research Society (IFORS). Composed of 50 national Operational Research (OR) societies, IFORS is a network by which OR professionals can exchange news, information, and ideas.
National Grid Electricity Transmission (NGET) owns and manages the distribution of electricity throughout the UK, which includes in excess of 60,000 assets. These include the familiar towers (pylons) supporting the cables which carry the electricity around the UK, plus associated circuit breakers, instrument transformers, grid transformers, and more. Maintaining the performance of these assets is an investment plan worth between £800 million and £1 billion a year, so the value of effective optimisation is very high.
Because the assets deteriorate over time, they need to be taken out of service for maintenance and/or refurbishment at regular intervals. This results in a loss of supply (outage) for the circuit containing that asset, which can be very costly. However it is possible to service more than one asset at the same time in a given circuit, a process called bundling, which will reduce the number of outages and hence the cost incurred.
Every outage comes with an associated direct and indirect cost. Outages must also be carefully coordinated so as not to disrupt the electricity transmission network. For example, it might be determined that out of a set of four circuits, only one may be taken out within a one-year period. Since each intervention also requires resources, such as personnel and spare parts, the planners must schedule these at a time when they are available. So the technical challenge is to find the optimal intervention schedule for each asset in the transmission network, while considering the benefits of bundling gains, the outage costs and resource constraints, plus any relevant business rules.
Copperleaf® has its headquarters in Vancouver and provides decision analytics to companies facing the challenges of managing critical infrastructure. Their enterprise software solutions leverage operational, financial and asset data to empower their clients to make investment decisions that deliver the highest business value. This project was carried out by their UK-based team.
Historically, the planning process had been manual, relying on a planner using his/her experience to recognise potential bundling opportunities, then building all the resource and outage requirements together into a deliverable package.
However, this approach could not take account of the non-linear calculations involved in estimating outage durations, since each viable solution will result in a different level of outage. This is a disadvantage of the manual approach. NGET and Copperleaf worked together to find improved solutions by combining the power of Copperleaf’s Decision Analytics Solution and its consulting and software development expertise, together with the engineering knowledge and prototypes that had been nurtured within NGET over the years. The innovative solution enables NGET to run network-wide optimisations involving more than 60,000 assets. These optimisations consider more than 5,000 interventions per year; 50 teams, each with up to five different resource types; and 100 overlapping boundaries for circuit constraint management.
Once NGET managers could see the potential benefits from the new optimised solution, they decided to embed it as a central part of their standard asset investment planning process.
While the prototype algorithm was developed using Python scripting, NGET made a conscious decision to implement the finished solution using a commercial off-the- shelf software package. The Copperleaf solution integrates asset, maintenance and investment data from existing enterprise systems, thus automating the data input process through eight programmatic integrations s) which run either:
- nightly (to import updated asset data, for example)
- monthly (to bring in existing investments that are fixed in the schedule, such as a commitment to connect a new customer)
- or ad hoc (to update risk model inputs, for example).
Monetised risk, asset intervention planning, and circuit optimisation can now be handled together in one simple, centralised platform. Instead of having to work with five different tools or spreadsheets, NGET planners can now find everything they need on a single screen in the Copperleaf solution. This has also helped to identify long-term resource requirements and pinch points across the network, where NGET needs to recruit and build resource capacity.
Training was provided to distinct teams within NGET to support their individual use cases:
- Enterprise Asset Management Lifecycle Team: Optimise asset replacement plans subject to risk and cost constrains
- Network Interventions Team: Optimise full lifecycle asset plans subject to cost, risk, and planned work
- Delivery Optimisation Team: Optimise plans subject to team, zone, and national resource constraints
- Network Optimisation Team: Optimise national plans subject to cost, resource and outage constraints
Enhanced asset lifecycle modelling has led to improved risk management, as well as ensuring that NGET selects the right interventions, at the right time, at the right cost for consumers.
The solution is now managed internally within National Grid with ongoing support provided by Copperleaf which includes membership of the Copperleaf client community and regular product upgrades and releases.
The new system went live in September 2019 and quickly delivered significant benefits, such as:
- Centralised Platform: for monetised risk, asset intervention planning and circuit optimisation, now one screen, instead of having to look at 5 different tools or spreadsheets.
- Improved Planning Efficiency: by reducing the time to build the plan for the fiscal year 2022 by 50% (from 12 weeks to 6 weeks). The increased agility and speed to carry out what-if analysis has been particularly important as NGET had to deconstruct the initial plan and rebuild it under different scenarios through the course of the COVID-19 pandemic.
- Reduction in Outage Costs of £2.5 million per year: The Copperleaf solution has reduced outage requirements across the network. For example, the number of circuits requiring an outage 3 times in a 5-year period has reduced from 18% to just 8%. Specifically, compared to manual bundling, Copperleaf’s optimisation for the Financial Year 2021 plan has increased the “Bundling Ratio” (number of interventions per outage) by 66%.
- Higher-value Plans: enhanced asset lifecycle modelling has led to improved risk management and ensured that National Grid selects the right interventions at the right time and the right cost for consumers.
- Strategic Workforce Planning: The output from the Copperleaf optimiser has also provided greater visibility into long-term resource requirements and pinch-points across the network where there is a requirement to recruit and build resource capacity.
“This is the most complex optimisation problem Copperleaf has ever solved. It recently won the Copperleaf 2020 Innovation Award, voted on by all Copperleaf clients globally.”
— Stan Coleman, Chief Technology Officer, Copperleaf
“The circuit optimisation solution is underpinned by a cutting-edge and complex algorithm that was co-developed with Copperleaf. This is helping NGET further improve our ability to anticipate and manage asset risks, ensuring we continue to make the right investment decisions across our
— David Wright, Group Chief Engineer, National Grid
Read the full September issue of IFORS here.