Key takeaways
Successfully completed first round of PSS testing at PNDC’s Wardpark facility
Demonstrated ability to reduce phase imbalance on LV networks
Improves utilisation of existing cable capacity and defers reinforcement
Reduces network losses and associated CO₂ emissions
Supports increased uptake of EVs, heat pumps and solar PV
The Challenge
The rapid growth of low-carbon technologies such as EV chargers, heat pumps and solar PV is increasing strain on low voltage (LV) distribution networks. Uneven distribution of these loads can lead to phase imbalance, resulting in reduced network efficiency, higher losses, voltage issues, and constraints on customer participation in flexibility services.
The Solution
The Phase Switch System (PSS) is an Ofgem Strategic Innovation Fund (SIF) Beta project led by National Grid Electricity Distribution (NGED), delivered in collaboration with UK Power Networks, Low Carbon Electric, Nortech and PNDC.
The system enables dynamic phase reconfiguration of LV feeder cables, actively balancing loads across phases. By managing phase imbalance, it can:
- Reduce loading on the most heavily loaded phase, improving fuse performance and network reliability
- Enhance utilisation of existing infrastructure and defer costly reinforcement
- Cut losses on the LV feeder, helping to reduce associated CO₂ emissions
- Lower the likelihood of voltage issues that could limit participation in flexibility services
The project is progressing from Technology Readiness Level (TRL) 6 towards TRL 9, alongside the development of a planning and optimisation tool to support targeted deployment by network operators.
Our Approach
PNDC provided a controlled, full-scale test environment where the PSS could be assessed under realistic network conditions—bridging the gap between lab validation and real-world deployment.
Working closely with project partners, the team supported the validation of the UK Power Networks–specified device, enabling performance to be tested against practical operational scenarios. This approach helps to surface potential issues early, build confidence in the technology, and reduce risk ahead of field deployment.
With testing hosted at PNDC’s Wardpark facility, the project benefits from an environment designed specifically to accelerate innovation—bringing together infrastructure, expertise and industry collaboration in one place.
The next phase will see testing shift to a National Grid Electricity Distribution–specific system, continuing to build evidence for how innovative LV solutions can support a cleaner, more flexible electricity system.
🔗 Find out more:
https://commercial.nationalgrid.co.uk/innovation/projects/phased-switch-system-pss
Connect with PNDC’s project lead and senior R&D engineer, Edward Corr on LinkedIn.