An investigation into dynamic photo voltaic array structures for the optimal power output of PV arrays under a variety of conditions including shading
RedFeather is Resource Exhibition and Discovery tool which is Feather light. It allows users to trivially upload and share small collections of OER. As well as the HTML interface metadata can be exposed in various formats including RSS, RDF and OAI-PMH. The tool is easily adaptable to into various Web2.0 services. Our plan is that the default user experience will visualize Resources using Google Docs Viewer and will allow commenting from Facebook.
The objective is to develop radically innovative electrical insulating tapes and process to improve the energy conversion efficiency of electrotechnical systems. It mainly addresses the electric power generation issue.
The ANASTASIA project consortium is equally composed of industrials and research laboratories, namely two manufacturers (tape and power generator), two generator end-users, four academic laboratories and the CEA research institute as the coordinator.
Context
Energy saving is a major societal issue that concerns a large field of technical applications, in particular electric power generation. The basic statement motivating the ANASTASIA project is that today the energy conversion efficiency of generators is restricted by (i) thermal as well as (ii) electrical strength limitations due, in particular, to the electrical insulation itself. The key feature of the generator field is that it deals with very long lifetime systems (40 years!). Consequently, it involves very traditional insulating materials and well established tape structures whose electrical properties and concepts are in fact far behind the current insulating material state of the art. As a result, high voltage insulating tapes are rather thick, poor thermal conductors and require energy consuming cooling systems. Today, high voltage insulating tape technology presents a very significant scope for progress that must be absolutely exploited to increase the generator conversion efficiency.
Expected outcomes
ANASTASIA aims to replace the current insulator tapes for high power applications. The current tapes are thick, semi-rigid and show poor thermal conductivity and mechanical stability. The goal is to replace this system with a thinner flexible structure, incorporating nanofillers and/or mica flakes. The objective is to increase the field strength from 2.5-3 to 4 kV/mm, to increase the thermal conductivity from 0.3 to 0.5 W/m.ðC, and to increase the thermal class from F 155ðC to H 180ðC.
Activities
To meet the objectives of the project, the ANASTASIA project will develop three complementary tape nano-structuration approaches:
A polymer route based on polymer/inorganic nanoparticle blending including a novel mica paper structure involving dielectric nano-flakes. This is a nanocomposite top-down approach. A polymer route based on in situ growth of dielectric nanoparticles. This is a nanocomposite bottom-up approach. A sol-gel inorganic based matrix for a quasi inorganic concept.
Southampton's role in this project is to run electrical testing on any samples produced by the consortium.
The Machine-To-Machine (M2M) applications of Wireless Sensor Networks (WSNs) and Wireless Body Area Networks (WBANs) are set to offer many new capabilities in the EPSRC themes of 'Healthcare technologies', 'Living with environmental change' and 'Global uncertainties', granting significant societal and economic benefits. These networks comprise a number of geographically-separated sensor nodes, which collect information from their environment and exchange it using wireless transmissions. However, these networks cannot as yet be employed in demanding applications, because current sensor nodes cannot remain powered for a sufficient length of time without employing batteries that are prohibitively large, heavy or expensive. In this work, we aim to achieve an order-of-magnitude extension to the battery charge-time of WSNs and WBANs by facilitating a significant reduction in the main cause of their energy consumption, namely the energy used to transmit information between the sensor nodes. A reduction in the sensor nodes' transmission energy is normally prevented, because this results in corrupted transmitted information owing to noise or interference. However, we will maintain reliable communication when using a low transmit energy by specifically designing channel code implementations that can be employed in the sensor nodes to correct these transmission errors. Although existing channel code implementations can achieve this objective, they themselves may have a high energy consumption, which can erode the transmission energy reduction they afford. Therefore, in this work we will aim for achieving a beneficial step change in the energy consumption of channel code implementations so that their advantages are maintained when employed in energy-constrained wireless communication systems, such as the M2M applications of WSNs and WBANs. We shall achieve this by facilitating a significant reduction in the supply voltage that is used to power the channel code implementations. A reduction in the supply voltage is normally prevented, because this reduces the speed of the implementation and causes the processed information to become corrupted, when its operations can no longer be performed within the allotted time. However, we will maintain reliable operation when using a low supply voltage, by specifically designing the proposed channel code implementations to use their inherent error correction ability to correct not only transmission errors, but also these timing errors. To the best of our knowledge, this novel approach has never been attempted before, despite its significant benefits. Furthermore, we will develop methodologies to allow the designers of WSNs and WBANs to estimate the energy consumption of the proposed channel code implementations, without having to fabricate them. This will allow other researchers to promptly optimise the design of the proposed channel code implementations to suit their energy-constrained wireless communication systems, such as WSNs and WBANs. Using this approach, we will demonstrate how the channel coding algorithm and implementation can be holistically designed, in order to find the most desirable trade-off between complexity and performance.
This project is concerned with a new approach to the condition monitoring and measurement for Partial discharge (PD) especially in terms of its location along high voltage transformer windings. PD may occur in a transformer winding due to aging processes, operational over stressing or defects introduced during manufacture. The presence of PD indicates a serious degradation and ageing mechanism which can be considered as a precursor of transformer failure. The concept developed in this project is based on the fact that the PD which occurred at any point along the winding produces a signal which contains high frequency components with a bandwidth up to 150-200 MHz, that will propagate as a travelling wave towards both ends of the winding eventually reaching a bushing core bar which will allow high frequency components of the PD signal to propagate to its tap point. In the experiment in the lab enviornment, the measurement of PD signals is obtained using Radio Frequency Current Transducers (RFCT) from both ends of the winding which are connected to earth via the bushing tap and neutral earth connection respectively. A new approach is need to be developed for location by using simualtion and digital signal processing techniques. An experiment has been developed that can be used to create common types of PD sources artificially in order to investigate the applicability of the proposed methods.
In order to provide a robust infrastructure for the transmission and distribution of electrical power, understanding and monitoring equipment ageing and failure is of paramount importance. Commonly, failure is associated with degradation of the dielectric material. As a result, a great deal of research and development focuses on understanding ageing of materials and designing methods for condition monitoring. Smart dielectrics are materials which contain a chemical group that produces a measurable response depending on local environmental changes. The introduction of a smart moiety into a chosen material is a potentially attractive means of continual condition monitoring as the system is passive (requiring no maintenance), provides a clear visual output indicative of the local environment, and could be applied to equipment as a coating or even make up part of the bulk dielectric. This project is a collaboration between the Tony Davies High Voltage Laboratory and the research group of Professor Richard C D Brown in the Department of Chemistry at Southampton University. It is important that any introduction of smart groups into the dielectric does not have any detrimental effect on the desirable electrical and mechanical properties of the bulk material. Liquid crystals are currently the subject of investigation as they are widely known to exhibit dramatic changes which are electric field dependant. It is possible to encapsulate droplets of liquid crystal in a host polymer to form a ââ¬Åpolymer dispersed liquid crystalââ¬? (PDLC). Such materials are manufactured into films which can then be used in a variety of applications. It is possible to rigorously control liquid crystal composition and material microstructure in order to produce PDLCs which ââ¬Åswitchââ¬? between clear and opaque states depending on changes in the local electric field, therefore making PDLCs potentially attractive smart dielectrics.
Electric propulsion (EP) can provide an order of magnitude increase in the specific impulse over conventional chemical propulsion giving significant reductions in the mass of propellant needed for a spacecraft. EP thrusters are being increasingly used on modern large telecommunications satellites, primarily for orbit control (NSSK). However, for attitude control chemical thrusters are used, meaning that two separate propellant types are required along with their associated storage tanks, flow control, etc.
There has been recent interest in replacing the chemical propulsion system with electric thrusters for attitude control (AC) thus providing significant systems advantages in terms of mass, complexity and integration. Such a spacecraft has been given the name, ââ¬ËAll-electric Spacecraftââ¬â¢.
One promising candidate for an AC thruster is the hollow cathode thruster (HCT). Hollow cathodes have been developed over the last 50 years or so and are used in gridded ion engines (GIEs) (for the main discharge and neutralizer) and in Hall Effect Thrusters (HETs) as an electron emitter. There is the possibility of using them as stand-alone thrusters (with an anode electrode) and most of the pioneering work on HCTs has been done at the university of Southampton. Nonetheless, the basic mechanism for thrust production has not been determined and the realization of a practical HCT with adequate performance for application to All-electric Spacecraft will need a much better understanding of the device.
To gain this understanding and to design and build a prototype thruster which could meet the necessary performance requirements, the European Space Agency (ESA)/ESTEC has recently funded a Technology Research Programme (TRP) project. Within this project, semi-empirical and analytic models will be developed, a thruster designed and testing to validate the models. Previous performance calculations have almost solely been based on indirect thrust measurements using a target pendulum onto which the thruster plume impacts; this method is not accurate enough and new measurements will be performed at Aerosapzio in Siena using a direct thrust balance. In addition, the effects on the application of a magnetic field to improve performance will be investigated both theoretically and experimentally.
Electric propulsion (EP) can provide an order of magnitude increase in the specific impulse over conventional chemical propulsion giving significant reductions in the mass of propellant needed for a spacecraft. EP thrusters are being increasingly used on modern large telecommunications satellites, primarily for orbit control (NSSK). However, for attitude control chemical thrusters are used, meaning that two separate propellant types are required along with their associated storage tanks, flow control, etc.
There has been recent interest in replacing the chemical propulsion system with electric thrusters for attitude control (AC) thus providing significant systems advantages in terms of mass, complexity and integration. Such a spacecraft has been given the name, ââ¬ËAll-electric Spacecraftââ¬â¢.
One promising candidate for an AC thruster is the hollow cathode thruster (HCT). Hollow cathodes have been developed over the last 50 years or so and are used in gridded ion engines (GIEs) (for the main discharge and neutralizer) and in Hall Effect Thrusters (HETs) as an electron emitter. There is the possibility of using them as stand-alone thrusters (with an anode electrode) and most of the pioneering work on HCTs has been done at the university of Southampton. Nonetheless, the basic mechanism for thrust production has not been determined and the realization of a practical HCT with adequate performance for application to All-electric Spacecraft will need a much better understanding of the device.
To gain this understanding and to design and build a prototype thruster which could meet the necessary performance requirements, the European Space Agency (ESA)/ESTEC has recently funded a Technology Research Programme (TRP) project. Within this project, semi-empirical and analytic models will be developed, a thruster designed and testing to validate the models. Previous performance calculations have almost solely been based on indirect thrust measurements using a target pendulum onto which the thruster plume impacts; this method is not accurate enough and new measurements will be performed at Aerosapzio in Siena using a direct thrust balance. In addition, the effects on the application of a magnetic field to improve performance will be investigated both theoretically and experimentally.