Phased Switch System (PSS)

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 services 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.

• Problem(s)

  The Low Voltage (LV) electrical distribution network serving homes and businesses is a three-phase alternating current system. Homes and businesses are each connected to one of the three phases and the selected phase changes from property to property down the street to try to spread load evenly between the phases. When the electrical loads across the three phases are not even, the imbalance reduces the Hosting Capacity (HC) of the network for further Low Carbon Technologies (LCTs) which can make the energy transition slower and more expensive as network reinforcement is required to provide the necessary capacity.

  With load imbalance, the highest phase current is most vulnerable to sudden surges and high load, which can occur at any time, resulting in substation fuses blowing causing blackouts. Thus, reducing the magnitude of this high phase current is crucial for enhancing the resilience of low-voltage networks. Network imbalance also results in more network losses and voltage irregularities.

  Our understanding of the problem has evolved during the the previous Phased Switch System (PSS) NIA project which has demonstrated the prototype's benefits. Increased LV monitoring of distribution substations has shown there are already substations with significant imbalance before this is increased by LCT deployment at volume, confirming the need for such a device. The NIA deployment showed the PSS;

  • can reduce instantaneous losses by 3.2 kW. This equates to an estimated 28 MWh annual energy savings for one feeder.
  • can manage dynamic imbalance profiles that cannot be addressed by transferring customers permanently from one phase to another due to the frequency of required changes.
  • boosts HC on today's typical feeder by 202A on average.
  • Provides 31A more additional capacity than reinforcement with 500A cables due to the active nature of the solution.

  Further details are included in the CIRED 24 paper. A final issue relating to imbalance is that where EV chargers or Solar photo-voltaic (PV) generators are not evenly distributed across phases. Clustering PV on one phase raises voltage more than balanced distribution. High voltage triggers automatic shutdown of EV chargers and PV generation. The impact varies; customers with fewer panels on their phase remain unaffected, while others may face restrictions on EV charging and/or energy trading. This project investigates the degree to which the PSS mitigates voltage issues as a natural result of reducing phase imbalance. This would benefit customers by ensuring fairer access to markets.

  In the Beta phase, DNOs and IDNOs, will have their needs addressed by implementing upgrades informed from NIA learning and widened ONO participation in planned workshops. Upgrades to the prototype will make it smaller, more robust, and less noticeable. Control functions will improve, and a planning tool will optimise implementation. This project advances from early prototyping to business implementation with an improved PSS, updated policies, and location selection planning tools.

  The project builds on two previous projects 

  • Smart Urban Networks - (SUN) -- unlocking capacity for low carbon technology in the electrical energy network: DESNZ (formally BEIS) Government Energy Entrepreneurs Project.
  • Phase Switch System PSS (PSS): UK Power Networks (UKPN) NIA Network Innovation Allowance Project. While DNOs and IDNOs are the main users of the PSS, other stakeholder impacts have been considered and reflected in the project activities.
• 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.

   

• Key Outputs and Learnings

  The key project outputs and partner responsible for delivery are as follows.

  • A finalised product design based on the results of the lab and field trials (LCE)
  • A simple Planning Tool design for later development and integration into ONO /planning engineers systems (NGED) • Final lab tests Report (PNDC)
  • Final Trials Outcomes Report (NGED)
  •  Supporting Policies to support the devices use (NGED)
  • BaU transition report and plans (NGED)

  The Project Sponsor will support the delivery of all outputs.

  Dissemination and Engagement Plans

  Engagement and/or dissemination activies are expected in all work packages as follows:

  WP1-Mobilisation

  We expect to:

  • Issue a press release to inform the industry of the project
  • Create a project webpage within the NGED innovation website. This will include background, and be updated to include progress reports, deliverables, etc. in addition to the ENA Portal .

  Within mobilisation we will also produce a Stakeholder Engagement plan. This will include:

  • stakeholder mapping
  • a customer engagement panel for those customers where the device will be trialled
  • internal engagement for installation engineers, faults team, policy team, training school etc. The team will engage in a number of activities across a variety of media including face to face meetings, training, virtual dissemination events. The plan will include how we will engageto track progress and share learning early.

  WP2- PSS Solution Technical Development and Testing

  This package build on the learning from the previous trial to finalise the designs, test the devices in the PNDC lab and build a planning optimisation software tool. Input into the required functionality, to be reflected in the design will be gathered via an interactive workshop hosted at PNDC open to any interested DNOs following an introductory workshop for project partners only.

  Workshop content will include an explanation by the technology developer (LCE) of the operation of the PSS and the network operator (NGED) will outline the benefits to the network. PNDC will provide a summary of previous PNDC testing outcomes and lessons learned and a live demonstration of the PSS on the PNDC test network .

  WP3- Planning Tool Development

  This package will develop a design for a planning tool for DNOs to use the device on their networks. These designs will be co-created with UKPN and then shared after an introductory webinar with the DNOs for comment. The final updated outputs will also be shared.

  WP4-Trials

  These are the field trials and the planning, execution and results of these will be shared with DNOs and other industry stakeholders. We will share our draft field trials plan with the DNO's for comment and then we will host some events with customers as part of the trials as well in coordination with local NGED colleagues.

  WP5- Post Trial Evaluation and BaU Proposal

  This package will evaluate the results, plan dissemination events and then work with the business to create a BaU transition plan. This will be shared as part of the closedown activities.

  WP6 -- Closedown

  At closedown we will publish all of our designs and learning and any policy documents along with our BaU plans. This will be done with key ONO stakeholders to ensure that they can utilise these results and plans for the benefit of their customers and businesses.

  Collaborative working

  We have approached UKPN to ensure that they are involved in the delivery of this project and intend to work with all DNO's and the ENA throughout the lifecycle of the project. We will as part of Mobilisation undertake a mapping exercise and review it throughout to ensure that all stakeholders and interested parties, including adjacent projects are engaged throughout.