- Date:
- 2007-2010
- Themes:
- High Voltage Engineering, Modelling and Simulation, Solid dielectrics
- Funding:
- EPSRC, SuperGen V, AMPerES
This project is concerned with establishing whether the occurence of switching/lightning impulses can lead to accelerated ageing of extruded cables. HDPE and XLPE material samples have been manufactured using a mold tool developed as part of this project. The samples then can be electrically aged using one of the high voltage laboratory's impulse generators. A real-time software based monitoring tool has been designed to control the impulse wave-shape and process the measurement data. The obtained results will inform the further development of models describing the multifactor ageing mechanisms that in-service cables experience. The electric field and potential profiles as well as the mechanical deformation of the sample will be observed when using different shaped electrodes.
Primary investigators
- Paul Lewin
- sgs
Secondary investigator
- nld06r
Associated research groups
- Electrical Power Engineering
- Electronics and Electrical Engineering
- Date:
- -2009
- Themes:
- Modelling and Simulation, Condition monitoring, Space and surface charge
The fact that the average service field of most insulating polymers used in high voltage systems is only a fraction (typically ~10%) of their breakdown strength has lead to the belief that the existence of space charges within the insulation may well be the key factor for its long-term electrical degradation. There has been a growing interest nowadays to investigate further the energy dissipation of these mobile and trapped charges and this dissipation process is associated with the emission of visible photons, a process known as electroluminescence (EL). Optical emission has been generally regarded as a direct proof of excited and chemically reactive states within the molecules so the study of the phenomenon could give a better understanding on the processes leading to polymer degradation. The aim for this project is to investigate the factors that influence the occurrence of EL under uniform electric field with the application of 50Hz ac stresses. EL intensity level was observed using a CCD camera and a set of filers were used to examine the spectral characteristics of this light emission. In addition to this, phase-resolved EL measurements were also obtained in order to see how the charge injection processes affect EL behaviour. A dynamic bipolar charge recombination model has been developed in order to allow the simulation of the phenomenon in a plane-plane electrode system.
Primary investigator
Secondary investigator
- ama04r
Associated research group
- Electronics and Computer Science
- Date:
- 2006-
- Theme:
- Industrial Monitoring
Researchers are working on a sensor network that will be capable of monitoring people and machinery in the University's new 55M Pound interdisciplinary cleanroom. The main aims for the system are to increase publicity and awareness (by "opening up" the cleanroom to visitors and staff/students), increase productivity (by allowing users of the cleanroom to see which machines are in use before entering the cleanroom). A primary challenge of the project is the ability of the network to be energy-efficient, while still providing a reasonably up-to-date and accurate impression of its monitored environment.
In addition to increasing publicity and awareness, the project will also provide a WSN showcase and development platform, and also be able to assist in the administration of certain areas of cleanroom management (by monitoring machine and personnel usage).
Primary investigators
- Geoff Merrett
- asw05r
Secondary investigators
- Luca Berti
- Nick Harris
- Neil White
- Bashir Al-Hashimi
Associated research groups
- Electronic Systems and Devices Group
- Electronics and Electrical Engineering
- Date:
- 2005-2010
- Theme:
- Nanoelectronics
Ni has been electro-deposited on n-type Ge wafers of various substrate resistivities. The Ni-Ge Schottky barrier is characterized and found to be of very high quality for highly doped Ge (0.005-0.02 é-cm) with leakage currents order of magnitudes lower than those fabricated by physical vapour deposition techniques eg. evaporation or sputtering. This technique could be used for low leakage Ge based Schottky barrier MOSFETs. On the other hand, the sharp Schottky interface of Ni to highly doped Ge is crucial for spin polarised carrier injection where the currents are explained by Thermionic field emission theories. Therefore, electrodeposition of a Ferromagnetic metal (Ni) on Ge is a viable fabrication technique for spintronic applications. This technique will be used to investigate spin injection into Ge.
Primary investigator
Secondary investigators
- mkh05r
- xl04r
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Date:
- 2005-2008
- Themes:
- Nanomaterials and Dielectrics, High Voltage Engineering, Solid dielectrics
- Funding:
- EPSRC
Morphology of polymers has been widely studied in order to enhance their structural properties. In the case of polyolefin, additives are often used to modify the morphology and improve the macroscopic physical properties. In the last decade, the use of nucleating agents has attracted many interests for improved optical and mechanical properties. Dibenzylidene sorbitol (DBS), a physical molecular organogelator, has shown nucleation efficiency on different polymers, like polyethylene (PE). This study investigates the effect of different amount of DBS on the nucleation and crystallisation of PE. A potential application as dielectric is given by the improved space charge distribution in samples containing DBS.
Primary investigator
- asv
Secondary investigator
- gg04r
Associated research group
- Electronics and Computer Science
- Date:
- 2005-2008
- Themes:
- Nanomaterials and Dielectrics, High Voltage Engineering, Solid dielectrics
- Funding:
- EPSRC
This project examines the structure and breakdown characteristics of a series of blends of polyethylene and an ethylene - vinyl acetate copolymer (EVA). The effect of adding a relatively polar copolymer composed of EVA , to a model polyethylene system is considered and relative electrical properties are studied.
Primary investigator
- asv
Secondary investigator
- gg04r
Associated research group
- Electronics and Electrical Engineering
- Date:
- 2007-2010
- Theme:
- Systems Design
- Funding:
- EPSRC
Otoacoustic emissions (OAE) are low intensity sounds produced by mammalian ears. They are generated by the activity of the outer hair cells in the cochlea and are a by-product of an active process that amplifies quiet sounds. OAE are normally associated with the clinical evaluation of the status of the cochlea and the assessment of hair cell functionality. It has often been commented that OAE appear unique to individuals and can be used to distinguish gender and ethnicity. This evidence suggests that OAE could be used to distinguish between individuals and could therefore form the basis of a biometric system.
Until recently, OAEs have never been studied with a biometric application in mind. This project is investigating the potential for an OAE to be used as a universal, unique, permanent and collectable biometric for identification purposes.
Primary investigator
Secondary investigators
- mel@isvr.soton.ac.uk
- jchad@soton.ac.uk
- Neil White
- Andrew Brown
- pc
Associated research group
- Electronics and Electrical Engineering
- Date:
- 2008-2009
- Themes:
- Interaction with Knowledge and semantics, Technology Enhanced Learning
- Funding:
- JISC
Semantic technologies appear to hold the promise of significantly enhancing formal and informal learning but certain issues such as building ontology consensus, the logistics of annotating large volumes of learning content and the underpinning pedagogy have been frequently questioned. However, recent developments in Web 2.0 tools and services for teaching and learning show that these concerns can be successfully addressed and benefit HE/FE, informal learning and exploratory learning.
This project will identify and quantify these benefits and outline a roadmap for semantic technologies adoption in these contexts. Addressing the HE/FE institutional perspective will involve case studies based on existing work.
Primary investigator
Secondary investigators
Associated research groups
- Learning Societies Lab
- Electronic and Software Systems
- Web and Internet Science
- Date:
- 2006-2009
- Themes:
- High Voltage Engineering, Nanomaterials and Dielectrics, Liquid dielectrics, Solid dielectrics
- Funding:
- EPSRC
In many items of high voltage plant such as transformers and cables, oil and paper is still used as the dielectric medium. In newer installations, especially underground transmission cables, a polymeric material is preferred. Much of this equipment was installed several decades ago with little thought as to its environmental impact or the associated decommissioning costs. Supergen, a project running for several years aims to redress this balance and look at more sustainable ways of distributing and producing electricity. The current project part of Supergen V: Asset Management and Performance of Energy Systems (Amperes) is looking at alternative materials and technologies that are more sustainable and recylable. The project has two major facets looking at solid and liquid insulation systems.
Solid insulation systems
Whilst crosslinked polyethylene (XLPE) is an excellent material for high voltage cables having excellent dielectric, thermal and mechanical properties, it does suffer from one major disadvantage; it is not easily recyclable. This facet of the project is looking into alternative, recyclable materials to replace XLPE in high voltage cables for the medium to long term. Polyethylenes, ethylene vinyl acetate co-polymers and propylene co-polymers have so far been considered. A realistic balance between good dielectric, mechanical and thermal properties using materials with a reasonable cost is sought.Liquid insulation systems
Whilst paper and copper can be readily recycled, the same is not true of the conventional mineral oils used in high voltage plant. Such oils are generally toxic and present a significant environmental hazard both in service and at ultimate disposal. This facet of the project is looking at alternative recyclable oils for high voltage applications. So far, dodecylbenzene and a range of different vegetable oil systems have been considered from the point of view of their ageing behaviour. A recyclable oil having the good properties of mineral oil but without the environmental drawbacks at a reasonable cost is sought.Primary investigators
- asv
- sgs
Secondary investigator
Associated research group
- Electronics and Computer Science
- Date:
- 2008-2010
- Themes:
- High Voltage Engineering, Liquid dielectrics
- Funding:
- National Grid plc
Silicone oil provides an excellent self healing liquid insulation system for high voltage applications and has minimal environmental impact. Unlike conventional hydrocarbon oils, it is capable of withstanding extremely high temperatures, such as those found in small transformers, and hence lends itself to more specialised applications outside of the reach of conventional oil/paper or polymeric insulation systems. These oils have also been used in terminations for many years with little understanding of their degradation or ageing behaviour and one noticeable problem is that these oils can become cloudy/black after relatively few years in service. The current project, in collaboration with National Grid, aims to quantify the effects of ageing on a range of silicone oils, to establish the pertinent chemistry and to identify suitable diagnostic tests to allow service engineers to make an informed decision of whether to replace or recondition plant.
The initial phase of the project concerned thermal and electrical ageing of a number of "model oil systems". A range of diagnostic indicators have been identified which provide indication of ageing in the field such as colour changes, oxidation, increased dielectric loss, formation of precipitates and increased viscosity. Whilst silicone oils are certainly capable of withstanding very high temperatures with very little degradation of thier dielectric properties, electrical ageing (even at moderate discharge energies) caused the oils to be rapidly blackened with significant deterioration in properties. It was clear from this work that electrical, rather than thermal ageing, is the dominant ageing mechanism under the conditions found in a typical termination and should therefore provide the focus for further work.
Construction of a new experimental apparatus to enable the study of electrical ageing on a local level (i.e. near the electrodes) is currently underway. Understanding the mechanism of ageing will provide pointers for improved designs to mitigate internal discharge activity and recommendations for more suitable oils or additives.
Primary investigators
- asv
- sgs
Secondary investigator
Partner
- National Grid
Associated research groups
- Electrical Power Engineering
- Electronics and Electrical Engineering