About the Project and Challenges
The UK faces an ever increasing demand for electrical power supply, especially in the areas of electric vehicle (EV) charging, PV panels for solar power and heat pumps, which is countermanded by the requirement to reduce the carbon footprint of electricity generation. Hence efforts to decarbonise energy generation, heat and transport will place increasing demands on distribution networks and its operators.
This is particularly so for the low voltage (LV) networks where distribution network operators (DNOs) have the obligation to supply electricity to customers within tightly defined voltage limits and at a sufficient quality (harmonics, sags, swells and flicker). From a recent industry study by Imperial College (London) it has been predicted that an increasing trend of voltage issues and demand rises that could potentially overload transformers and underground cables, requiring large investment from DNO over a period if reinforced by conventional means. UK Power Networks (UKPN) is one such DNO who is facing this challenge and with support and funding from Ofgem and collaboration with various key stakeholders including Imperial College and Turbo Power Systems is trying to provide a sustainable and reliable low voltage flexible urban networks (FUN-LV). UKPN has selected 36 trial sites for this project.
Objective of the FUN-LV Project
The overarching aim of this project is to explore how the use of power electronics can enable DNOs to defer reinforcement and facilitate the connection of low carbon technologies and distributed generation in urban areas, by meshing existing networks which are not meshed, and by breaking down boundaries within existing meshed networks. Power electronics devices (PEDs) will be used for the first time, in combination with remote configuration and informational tools, to access latent/spare capacity that already exists, in shorter timescales than conventional reinforcement. The smart grid technology of FUN –LV will enable DNO to meet their obligation towards enabling the growth of Government led initiatives for low carbon technologies as there is no major re-structuring of the grid system and this greatly minimises the impact on infrastructure capital cost.
There are three objectives to this project and they are as follows;
• Optimise capacity on the low voltage (LV) network closest to customers
• Improve connection offers (time & cost) in urban areas
• Advance the future network architecture debate for the sector
UKPN chose TPS to supply the PEDs and this was underpinned by the proven experience and pedigree of TPS in the supply of power electronics to the energy sector.
The technology proposed by TPS utilises Power Electronic Devices (PEDs) which can enable the meshing of low voltage urban networks and these devices act as soft open points (SOPs) between distribution substations for capacity sharing and which like a tap can be fully open, fully closed, or at a setting between these limits. The solution uses a cutting edge and novel bi-directional PED developed by TPS to integrate with the transmission network to enable UKPN achieve the objectives of this project. The proposed PEDs come in two formats, with two and three terminals, allowing power flows of up to 400 kVA between 3 substations, thus making use of spare network capacity at existing substations rather than building new capacity. The bi-directional PED achieves transfer of power both from supply to consumer and consumer to supply, enabling power sharing between consumer loads. Thus the resultant network becomes ‘smart’ with the reduction of load on transformers and a faster response to Low Voltage demand changes.
Key Benefits to the DNO and its customers:
• Flexibility to manage uncertainty
• Control functionality
• Maximise the use of existing assets
• Faster and more cost-effective connection offers
• Improved quality of supply
• Reduced disruption and logistical benefits
• Flexible network architecture
• Better enabled distributed generation connections
• Connection and sharing of generation or loads across two or more circuits’ ‘incompatible feeders’ –
• A significant saving in money and infrastructure – potentially £2.36M across the 36 trial sites which could be upscaled to to £112.8M across the UK