Following a series of serious power blackout incidents in 2003, policy makers in the European Union and the USA have highlighted (i) the need for improved a.c. transmission grid infrastructure and advanced control technologies to enhance stability and security in an increasingly complex operating environment, and (ii) the importance of emerging measurement-based technology towards achieving such enhanced operation. The concept of this proposal is a system for transmission security assessment using the emerging measurement technologies of high-bandwidth SCADA systems and the wide area measurement systems (WAMS) which are based on time-synchronized phasor measurement units. It will lead to better situational awareness and initiate control action for optimal operation closer to loading constraints while reducing the risks of blackouts.Very recent developments in measurement-based analyses being used in oil, gas and chemicals plants point the way towards much better signal analysis applications for the emerging measurement-based technologies in power transmission systems. The measurement-based system proposed in this project would greatly extend the basic methods that are used at present and will lead to localization and real-time diagnosis of the root causes of threats to transmission system security and actions to control the situation. It offers a more predictive, responsive and accurate approach than the transmission system models which are currently used, while the signal analysis methods now being used in experimental WAMS and high-bandwidth SCADA systems would advance from their current narrow emphasis on Fourier methods adopted from the aerospace industries. For instance the project would develop signal analysis methods for use when transient events excite system non-linearities. This will provide a much more accurate indication of the true situation during developing emergencies.This project is timely and is giving an immediate response to research needs identified in the Spring of 2006 in policy documents from the EU and US. Success in shifting the emphasis from model-based to measurement-based assessments will benefit the wider field of a.c. transmission stability and security as well as creating an a.c. transmission security enhancement system in a fit state for technology transfer. A first-rate team has been assembled for the task, namely Imperial College London (expertise in robust damping control of inter-area oscillations) and UCL (expertise in measurement-based analysis for process systems), National Grid (provision of high-bandwidth SCADA data, system specification and testing, a UK industrial viewpoint) and ABB (provision of PMU data, system development, the industrial viewpoint from continental Europe). The university researchers will do part of the work on secondment with National Grid and ABB. It is quite realistic to expect success from this team.

Following a series of serious power blackout incidents in 2003, policy makers in the European Union and the USA have highlighted (i) the need for improved a.c. transmission grid infrastructure and advanced control technologies to enhance stability and security in an increasingly complex operating environment, and (ii) the importance of emerging measurement-based technology towards achieving such enhanced operation. The concept of this proposal is a system for transmission security assessment using the emerging measurement technologies of high-bandwidth SCADA systems and the wide area measurement systems (WAMS) which are based on time-synchronized phasor measurement units. It will lead to better situational awareness and initiate control action for optimal operation closer to loading constraints while reducing the risks of blackouts.Very recent developments in measurement-based analyses being used in oil, gas and chemicals plants point the way towards much better signal analysis applications for the emerging measurement-based technologies in power transmission systems. The measurement-based system proposed in this project would greatly extend the basic methods that are used at present and will lead to localization and real-time diagnosis of the root causes of threats to transmission system security and actions to control the situation. It offers a more predictive, responsive and accurate approach than the transmission system models which are currently used, while the signal analysis methods now being used in experimental WAMS and high-bandwidth SCADA systems would advance from their current narrow emphasis on Fourier methods adopted from the aerospace industries. For instance the project would develop signal analysis methods for use when transient events excite system non-linearities. This will provide a much more accurate indication of the true situation during developing emergencies.This project is timely and is giving an immediate response to research needs identified in the Spring of 2006 in policy documents from the EU and US. Success in shifting the emphasis from model-based to measurement-based assessments will benefit the wider field of a.c. transmission stability and security as well as creating an a.c. transmission security enhancement system in a fit state for technology transfer. A first-rate team has been assembled for the task, namely Imperial College London (expertise in robust damping control of inter-area oscillations) and UCL (expertise in measurement-based analysis for process systems), National Grid (provision of high-bandwidth SCADA data, system specification and testing, a UK industrial viewpoint) and ABB (provision of PMU data, system development, the industrial viewpoint from continental Europe). The university researchers will do part of the work on secondment with National Grid and ABB. It is quite realistic to expect success from this team.

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.

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.