Researchers in Electronics and Computer Science (ECS) at the University of Southampton are working with major industrial partners to develop new high voltage cables that can meet the demands of future energy needs, save millions of pounds annually, minimise the risk of network failure, and cut carbon emissions.
The transmission of electricity through cables is an increasing issue as the power demand of large urban areas rises, as we seek to minimise the impact of overhead lines on the environment and as offshore renewable generation grows. To meet this challenge, it is imperative that we maximise the ability of our electrical networks to transmit power reliably from generators to load centres.
However, many aspects of the technology for transmitting this power, such as underground coaxial cables, overhead lines and transformers have not significantly changed since the National Grid was created in the 1960s.
The UK’s current electricity transmission and distribution systems are almost exclusively based upon alternating current (AC). In most cables, the key insulating material has a maximum operating temperature of approximately 95˚C and the power flows are largely controllable. However, if a cable link needs to be worked hard, this can result in overheating of a cable and if this occurs too often or to too great an extent, the subsequent breakdown of a network is a serious threat. In the most extreme circumstances this overloading could cause permanent damage and lead to blackouts.
The future will see the UK less reliant on controllable, conventional forms of energy and more reliant on renewable forms, which are intermittent. The consequent lack of control poses a higher risk of overloading cables, resultant damage and loss of power to consumers. Our electricity transmission and distribution networks need to be re-designed so they are able to withstand the variable energy outputs from renewable generation and transmit energy economically around the UK.
ECS researchers, led by Professor Alun Vaughan, Professor Paul Lewin and Dr James Pilgrim, have been collaborating with a range of industrial partners including National Grid and GnoSys Global, to manufacture sophisticated materials that can adequately insulate new high-voltage cables, be less energy intensive in their production, be fully recyclable at the end of their life, and offer network businesses enhance operational flexibility where renewable sources of generation remove the control that they have traditionally enjoyed.
The research has been significantly funded by the Engineering and Physical Sciences Research Council (EPSRC) and Innovate UK - the Technology Strategy Board. Further EPSRC funding is allowing the team to explore the development of high voltage direct current (HVDC) cables that can be used at extremely high voltages. These will greatly increase the efficiency of energy transmissions over long distances, such as from an offshore wind farm to shore.
Southampton’s research is having a significant impact on how the UK responds to its future energy demands.
Production of new high voltage cables will help ensure the resilience of our changing energy distribution networks, while more accurate rating methods for existing cables are already saving National Grid more than £1.2m annually.
The recommendation of new techniques such as improved modelling of ventilated tunnels is having an impact in terms of reduced environmental impact – reductions in cooling system running using our new control scheme has been estimated to deliver electricity cost savings of around 60%
The University’s world-class Tony Davies High Voltage Lab has also worked with Centrica Energy to test high voltage AC offshore wind farm export cable. The results of this testing programme could lead to improved international standards for the rating of offshore wind farm export cable circuits.
The research has led to an increased emphasis on raising public awareness and engagement. The team are involved with the Council on Large Electric Systems (CIGRE) working parties, have produced a range of industry documents and are taking their Please Don’t Buy an Electric Car talk to the community through the Virtual Cafe Scientifique.