Project Summary
The Phase Switch System allows for dynamic phase reconfiguration of a Low Voltage (LV) feeder cable to reduce phase imbalance. Reducing phase imbalance;
- reduces the load in the most heavily loaded phase, decreasing the chance of incorrect fuse operations
- improves the utilisation of the cable's capacity, deferring reinforcement
- reduces losses on the LV feeder and associated CO2 emissions
- reduces the likelihood of customer voltage issues preventing participation in flexibility serivices or other markets
This project further develops and tests an existing protype to market readiness while providing a support tool for planning and optimisation of deployment.
Innovation Justification
The PSS Solution is a novel answer to a significant LV network challenge. As customers adopt Low Carbon Technologies (LCTs) there is a risk of increased phase load imbalance reducing hosting capacity and triggering reinforcement.
However, the PSS may provide value for money by providing a cheaper alternative that also reduces losses and the risk of non-fault fuse operations.
The PSS prototype, previously trialled as part of an NIA project, will be taken to the next level by improving the technical design to reduce the footprint, simplify and improve operation while eliminating noticeable flicker. The Beta project will undertake lab and field testing, and create the policies for wider rollout reflecting the revised design and trial results. However, while the PSS shows considerable promise, the project risks and costs, along with the project scale and duration suggest that SIF is a more appropriate funding mechanism than NIA or BAU funding.
The project addresses Challenge 3: Improving energy system resilience and robustness ; Strengthening the UK's energy system robustness to support efficient roll out of new infrastructure. It also will add to the wider ability of consumers to adopt low carbon technologies.
The PSS strengthens the robustness of LV networks through its ability to minimise the maximum phase current. This mitigates the risk of premature fuse blowing or phase overload.
As PSS was not an Alpha project, we have embedded sharing of information into our project plan. We intend to work with UKPN but also share our insights and learning during the project with the ENA and other DNOs, providing them all with the relevant information to make informed decisions about adopting PSS as a solution.
Innovation comes from the fact that this device has the potential to change the way DNOs manage the LV network in a way that supports Net Zero objectives. The scale of the trials and testing in PNDC makes this the first trial of its size. Additionally the coordinated planning of site locations to maximise benefit is novel.
Phase 1 trialled TRL 6 PSSs on UKPN's distribution network. Beta will address the learning points and enable progression to TRL 7-8, boosting investor confidence for a Series A funding raise in 2027. Accelerating manufacture at the right time to meet emerging LV network reinforcement markets.
The PSS design met ONO and customer needs for Phase 1, and the partnerships established enabled a PSS certification plan to be constructed for Beta. Market readiness is at CRL6, Beta will advance to CRL7, and the subsequent Series A raise in 2027, assures progression to CRL8-9.
The PSS's capability to reinforce through balancing phases at Phase 1 demonstrated IRL6 using network data. Beta enables progression to IRL7 by providing the arena for LCE, NGED and Nortech to collaborate and integrate PSS data on NGEDs servers.
The scale of the project will be 7-9 field trial sites, tested over at least a 12 month period, this will be coupled with an extensive two product lab test at PNDC. This will be supported by the NGED Policy Team to ensure that the device meets required standards and can be safely installed, operated, maintained and decommissioned..
A planning tool will be developed to determine the likely benefit of using the PSS at different sites, including comparison with jointing options to reduce imbalance. This will enable an optimised programme of deployment to be developed. The robust and significant testing, trials, policy development and site selection tool provision will ensure that the business has the confidence and evidence to support we can move quickly to implementation within BaU This will support the Challenge 3 objective.
Impacts and Benefits
The PSS will deliver partial benefits within the project term. However, significant benefits are expected from BaU rollout, therefore the project will confirm and update the CBA to evaluate justification for rollout.
Baseline assumptions
The baseline assumptions for the CBA are for the current network with no PSS devices installed. Some manual customer re-phasing activity is anticipated but this is expected to have a limited lifetime with additional LCTs changing the load imbalance unpredictably. Feeders with high imbalance are expected to have high rates of fuse operations.
Financial - future reductions in the cost of operating the network
Reductions in the cost of operating the network come from
1) Fewer unintended fuse operations (which would also provide CI/CML benefits)
2) Reduced / delayed network reinforcement in order to support LCT installations
While the trial will not defer reinforcement, we can measure the degree of released capacity on the LV network and using forecasted load increases determine the number of years reinforcement would be deferred by. The reduction in losses on the LV network, the increased headroom between the load and the fuse rating and any reduction in losses for the 11kV transformer will be captured as part of the project.
The CBA for targeted roll-out shows a net lifetime financial benefit of £230m and an NPV over 45 years of £371m.
Environmental - carbon reduction -- direct CO2 savings per annum
The project will measure the change in phase and neutral currents which can be used to calculate the reduction in losses on the LV feeders. Additionally, we expect to install PSS devices on all LV feeders downstream of a transformer in order to accurately measure the reduction in transformer losses.
With a targeted roll out, net savings of 3.12 TWh of losses are expected over the lifecycle of the devices and 24,322tC02e of carbon savings. This would equate to
£129m of benefit to customers.
Financial - cost savings per annum on energy bills for consumers
While voltage issues are increasing, the degree to which customers are prevented from participating in markets is not currently known. The project will compare customers' smart meter voltages when the PSS devices are operating or not operating. This will indicate the improved access to markets as voltage issues are reduced.
Whilst these benefits are difficult to measure we would expect to see increased participation in markets for balancing and flexibility services. While some service payments are modest, smart car charging benefits can save customers several hundred pounds a year.
Benefits from carrying out LV network upgrades in a planned rather than reactive manner
The trial will provide metrics for exactly how much imbalance reduces network capacity. By selecting locations with high rates of LCT installations we will measure the additional impact of multiple EV chargers or multiple PV installations. This will allow our estimates of when reinforcement would be required to be updated.
Similarly, the development of the optimisation tool will provide better information on the number of sites where PSS deployment is beneficial and an optimised installation plan. The benefits of installations being carried out in a planned rather than reactive manner are expected to result from being able to have a dedicated team that are able to build expertise and therefore carry out installations faster.
Having an optimised installation plan will also allow installations in the same area before moving onto the next area. This should reduce travel and other expenses for the installation teams.
Both targeted and more widespread roll out approaches show significant benefits. The planning tool would help DNOs to optimise installations to locations likely to provide the highest benefits.
