Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Renewable Energy Systems Technology (CREST)

Networks & Systems

Low-Voltage networks

The introduction of photovoltaics, electric vehicles and heat pumps has major implications for the operation of low-voltage (LV) networks: the 400 V three-phase and 230 V single-phase circuits that connect to individual homes and other buildings. These networks represent an enormous national investment – most of it underground, out of sight and out of mind. They have been installed over a period of almost a century and have served very well in delivering power to the multitude of electrical appliances that now facilitate our daily lives. The challenge presented by photovoltaics, electric vehicles and heat pumps (low-carbon technologies) is that they are high-power and typically run for many hours each day. Isolated installations are readily accommodated within existing networks, but mass up-take will dramatically alter the power flows in LV networks and the unattractive conclusion of a simplistic analysis is that these networks will need wholesale upgrade. The associated costs and disruption (road digging) create strong economic and social imperatives for getting the best out of existing networks and knowing exactly where best to target any required investment.

Perhaps surprisingly, the detailed operation of these networks is not entirely known. Certainly, there are well-proven design methods and operational strategies that have very successfully led to the highly reliable system that we are familiar with today. But, when we look closely at the detailed operation of specific networks in practice, it is not at all uncommon to find things operating either hotter or cooler than expected. And thus, the assessments of where we may or may not connect low-carbon technologies may be on an uncertain footing. This could lead to unnecessarily constrained installation of low-carbon technologies, poorly targeted network upgrades or even operational difficulties eroding network reliability. Our research aims to minimise these uncertainties. We are developing detailed analysis techniques that can provide accurate assessment of network headroom and pinch-points and so provide a reliable view of what can be installed where and how best to target any required network reinforcement.

Detailed studies of LV networks are greatly complicated (in comparison to studies of higher-voltage networks) by a combination of the following factors.

Examples of our publications in this area include:

Urquhart, A.J. and Thomson, M., 2013. Assumptions and approximations typically applied in modelling LV networks with high penetrations of low carbon technologies. Solar Integration Workshop 2013, London, October 21st-22nd 2013, 6pp. Available here: https://dspace.lboro.ac.uk/2134/13425 

M. Thomson, D.G. Infield, 2007. Network power flow analysis for a high penetration of distributed generation. IEEE Trans Power Syst, 22 (2007), pp. 1157–1162