There are two very particular places in energy networks where existing network technology and infrastructure needs radical change to move us to a low carbon economy. At the Top of network, i.e. the very highest transmission voltages, the expected emergence of transcontinental energy exchange in Europe (and elsewhere) that is driven by exploitation of diversity in renewable sources and diversity in load requires radical innovation in technologies. Many of these proposed interconnectors will be submarine or underground cable and High Voltage Direct Current (HVDC) must be used. Power ratings for the voltage source AC/DC converters for HVDC use are presently around 500 MW while the need is for links of up to 20 GW. A change of this magnitude requires radical innovation in technology. To focus our research in HVDC cable technology and power converters we have defined target ratings of 1 MV and 5 kA. The Tail of the network is the so-called last mile and behind the meter wiring into customer premises. More than half the capital cost of an electricity system is sunk in the last mile and cost and disruption barriers have made it resistant to change. Not only have recent changes in consumer electronics yet to impact network design, there are radical changes in future heat and transport services that need to be met. The challenge is to reengineer the way in which the last mile assets are used without changing the most expensive part: the cables and pipes in the ground. To get this right means starting with a fresh look at the energy services required and seeing what flexibility there is to meet the service expectation differently. A consortium of universities has been brought together to address this transformation of our energy networks. Several of the bid partners have had leading roles in Supergen consortia in the networks area but this consortium includes new partners whose expertise, especially in the power electronics field, is strongly indicated as game-changing. For the first time, the power electronics researchers in Warwick, Nottingham, Imperial and Strathclyde and the insulation materials groups in Manchester and Southampton are proposing to work together bringing developments of underpinning technologies to bear on network issues. These technology developments are folded into the energy network planning and operations work of Strathclyde, Manchester, Cardiff and Imperial. Birmingham brings energy economics expertise and Imperial expertise in energy policy and the social science of consumer acceptance. Several important industrial companies are engaged with this programme to form our scientific advisory board and to pick up and use results that emerge. These in clued network operators such as National Grid and Central Networks, equipment manufacturers such as Alstom Grid and Converteam and component manufacturers such as Dynnex and Dow Chemicals.Although the proposed project will address major challenges of technology, we recognise that transforming our energy networks is not merely a technical question. Members of the consortium already have links with civil servants and advisors in a number of administrations in the UK including DECC, the Scottish Government, WAG and NIE. These links allow us to understand the context in which energy policy is made. Consortium members have given advice to Ofgem on the Low Carbon Networks Fund, Parliamentary Select Committees and have been active in projects commissioned through the Energy Technologies Institute. Thus although the focus of your project is on a timescale of 20-40 years the results of our research will impact network development much earlier. Discussions to date with our partners in these organisations suggest a great deal of excitement about what work on the Energy Networks Grand Challenge can contribute.

The aim of this proposal is to appoint an additional professor in the field of electrical energy and power systems at The University of Manchester. Since candidates for this position cannot hold a permanent academic position in the UK, his/her appointment will increase the pool of experienced researchers working in a field that has been recognised as being not only critical to the health of the UK economy and quality of life but also below the critical mass required for a sector undergoing a major transition.

The ever increasing demand for electricity consumption accompanied by environmental pressures impose a continuing need for electrical systems modification and growth, partly because of changing operational practices resulting from de-regulation and, partly, due to the increased use of distributed generation, which is changing the demands on transmission and, especially, distribution lines. But for many years now, the opportunities for installation of new lines have become very limited because of public concern over visual and other environmental impacts, and it is clear that extensions to system capacity will have to be met substantially without new lines.The voltage rating and the insulation coordination of transmission and distribution lines is determined by a combined consideration of the voltage stress applied to the line and its electrical strength. The stress arises from overvoltages due to switching transients or lightning surges. The magnitude of the switching overvoltage is controlled by the characteristics of the system components, and is more critical at the highest operating voltages. Lightning overvoltages, on the other hand, are of much larger magnitudes and are more onerous to distribution systems.IEC 60071 makes recommendations for the gaps and clearances to be used for specific voltage levels, and individual operators will then adopt safety factors above and beyond these recommendations, depending upon local conditions. Pollution, for instance, may reduce the breakdown voltage by up to 50%. These adopted clearances are usually very generous and can be optimised using modern equipment and practice.The investigators have researched for many years the possibilities for compact lines and substations through improved co-ordination of insulation and the use of polymeric insulators and more effective protective devices such as ZnO surge arresters. This programme, therefore, proposes to apply the compact line concepts to the up-rating of existing lines. It will involve statistical studies of switching and lightning surges that account for various parameters which affect the overvoltage magnitudes, such as closing times for circuit breakers and analysis of the possible state of the line in order to minimize the risk of re-closing onto trapped charge. The statistical variations of stress and strength of the system will be combined in a voltage-frequency plot to determine the risk of failure, which has to be minimized within economic constraints. The stress will be presented as the probability of a certain overvoltage occurring, and its distribution along a line will be controlled by the judicious placement of modern ZnO surge arresters. Electrical strength, on the other hand, can be presented as a probabilistic breakdown curve. It will be primarily derived from consideration of the breakdown curves taking into account the critical clearances at the tower and along the line. These principles have been studied over the years, but present-day pressures are causing a re-evaluation of the conventional limits and methodology. This is also supported by the excellent performance of modern ZnO surge arresters in controlling overvoltages and the superior pollution performance of new polymeric insulators. The programme will also include laboratory and field experimental programmes to test and characterise the new devices and configurations to be used for the compact design of the uprated lines. The main output of the programme is to establish well researched fundamental principles that will allow an efficient and safe design for the future transmission and distribution lines.The basis of this programme has been proposed by HIVES, Cardiff University and then moderated by discussions with an industry group involving National Grid, four UK DNOs, ESB and three line construction companies, whose views are embedded in the proposed programme.

Electricity transmission and distribution companies in the UK face serious challenges in continuing to provide high reliability from ageing networks. This is made more difficult by increasing economic and environmental pressures. The problems will become worse as the operating conditions of the networks are changed, to allow for the production of more electricity from renewable sources.To meet this challenge, network owners and operators need better knowledge of plant ageing and improved techniques to monitor its condition.As power is generated in different locations, so the pattern of current flow through the network changes. This alters the temperature of plant items (like transformers, overhead lines and underground cables), which make up the network. Other changes in operating conditions, such as when switches are operated, will affect the stresses seen by plant. We will investigate the effect of the new operating demands on individual items of plant in order to predict their effect on the reliability of the network.We will also investigate some innovative techniques for monitoring plant condition. These will range from techniques which give a general indication of the health of an entire substation, down to those which give detailed information on a specific item of plant. The work will look at new sensors, data capture, data management and data interpretation. Network owners and operators also need improved methods of protecting and controlling the network. New software tools will help them plan replacements as parts of the network wear out. Our work will help get the most power through the ageing network and allow owners to invest in new or replacement plant in a cost-effective way. All this has to be done while maintaining or improving the security of supply and taking into account interactions between gas and electricity networks. Software tools will be developed to calculate the optimum size and location of new generating plant and to calculate the cost that should be charged to transport electricity from a particular location.Finally, research into electrical plant with reduced environmental impact will allow the use of environmentally friendly replacements. There are three main aspects to this work: exploring methods of reducing the use of SF6 (a greenhouse gas), examining techniques for transmitting more power down existing lines and investigating methods of reducing environmental impacts (for example, oil leaks) from underground cable.EPSRC has assembled a team of six universities, which have the skills needed to tackle these challenges. These universities have worked closely with major electric utilities and equipment manufacturers to prepare this proposal. The industrial partners will provide a valuable contribution, both through funding and also by supplying their technical expertise and guidance.Our work will benefit electricity utilities, which will spend less on maintenance and get more for their money when buying new plant. Consumers will gain through improved reliability of their electricity supply. UK manufacturers will be able to exploit the new condition monitoring and diagnostic techniques. Society in general will benefit through reductions in environmental impact.

Power transformers are designed to withstand the mechanical forces arising from various in-service events, such as over-voltage and lightning, which may cause deformation or displacement of winding. Among various techniques applied to power transformer fault diagnosis, frequency response analysis (FRA) can give an indication of winding deformation faults without expensive and interruptive operations of opening a transformer tank, which can minimise the impact on system operation and loss of supply to customers and consequently save millions of pounds in timely maintenance. However, in industrial practice, FRA is always used as a comparative method, by comparing a test frequency response with a reference set, which cannot provide an insight understanding of transformer internal faults. A range of research activities have been undertaken to utilise FRA in the development winding models but with limitations, such as too complicated models, large computation time and inaccurate responses in the high frequency range between 1MHz and 10MHz. The proposed research is to build on the experience already gained at Liverpool and to develop an accurate winding model and a reliable fault diagnosis approach. A new hybrid winding model will be developed by modifying the analytical approach and results of transformer winding analysis obtained by Rudenberg for each disc, and subsequently connecting the travelling wave equation of each disc in a form of Multi-conductor Transmission Line (MTL) model. This can significantly reduce the order of the model yet with good modelling accuracy in the high frequency range, which allows access to the current and voltage at any desired turns of a winding. The electrical parameters of the hybrid model will be estimated with the finite element method (FEM), and further identified with evolutionary algorithms based on actual FRA measurements. The characteristic signatures between particular winding faults and winding parameters will be derived, which can be employed to detect and distinguish winding deformation faults. Then, the simulation of the hybrid model will be used to extract high frequency fault fingerprints of FRA for improving the detection of small winding changes, which will be further examined and verified through laboratory studies. For typical winding fault diagnosis, both the quantitative and qualitative judgements are generally considered, which can be treated as evidence and are often incomplete and imprecise. The Evidential Reasoning (ER) algorithm is very suitable for combining such evidence with a firm mathematical foundation. In this project, an evidence-based fault diagnosis system will be constructed to aggregate diagnosis information and deal with uncertainties for reliable winding fault diagnosis. The work is to be carried out as a collaborative project between the University of Liverpool, OMICRON and NG, bringing together academic and industrial expertise in the field of transformer test, modelling and fault diagnosis. The outcome of the proposed research will be the new hybrid winding model and the evidence-based winding fault diagnosis system. The new approach aims to improve the fundamental understanding of multi-frequency signal propagation across a winding, which will allow extracting fault fingerprints in both the low and high frequency ranges and provide new diagnostic rules for early fault detection and location. The extracted high frequency fault fingerprints will provide a feasible solution for early fault detection, which can assist a FRA test kit manufacturer, e.g. OMICRON, in fully understanding FRA and improving test kit precision. The developed evidence-based system for winding fault diagnosis can be a useful decision support tool for utility companies, e.g. NG, for reliable fault diagnosis yet with high efficiency, when processing numerous FRA records.