摘要:

The review has been prepared by staff of the CEGB who are actively studying different aspects of large-scale electrical energy storage. Some areas, such as pumped storage, have been studied in considerable depth, since this technique has been exploited commercially for many years in many parts of the world. Other topics, such as superconducting magnetic storage, are at a much less advanced stage of development and are still at the laboratory and paper study stage. The review starts by examining the role of storage on an electricity-supply system. At present, the major use is put to reducing the flexibility requirements on other plant, but in the future, load smoothing for use with those systems with a large nuclear component could be important. The benefits and limitations of storage in conjunction with renewable energy sources are also discussed. Turning to the technical possibilities, a description is given of the widely used pumped hydrostorage technique. Potential development such as the use of an underground lower reservoir are discussed. It is possible to store the compression energy of a gas turbine as compressed air in an underground cavern. A plant operating on this principle has been built at Huntorf in Germany, but it requires a premium fuel such as natural gas or distillate oil. The possibility of developments leading to a reduction or elimination of this fuel requirement are discussed. It is also possible to store hot water at a power station and re-use it in the steam cycle. This technique has had some practical use for many years and its advantages and disadvantages are discussed. Batteries have been used for storage for many years, but current types are generally too expensive for use for large scale electrical utility applications. The state of development is discussed of new types, which although primarily envisaged for use with electric vehicles, could be used in central stores. Flywheels are also being developed for use with electric vehicles and their potential application to large-scale electrical energy storage is reviewed. Perhaps the most technically advanced storage technique would be to use a large superconducting magnet. The status of studies of this possibility is described. Finally, the relative advantages and disadvantages of the various technical possibilities are discussed.

DOI:10.1049/ip-a-1.1980.0054

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Soft magnetic materials have symmetricalB/Hcharacteristics which form closed loops for alternating magnetisation between positive and negative saturation levels of flux density,B. The model suggested here produces these ‘nesting’ characteristics by making the coercive force proportion to the maximum flux density. The deviations between ascending and descending curves are modelled in a single expression in which theB/Hcurve and a defined hysteresis parameter are used. The simplicity of the model makes it valuable for use in electromagnetic applications in which soft iron materials are used, and the representation of hysteresis is crucial. It is primarily intended for the representation of high magnetisation, but can be amended to represent cycles of low magnetisation. The inrush current of a single-phase transformer is calculated, and the method is suitable for obtaining inrush current in any power equipment.

DOI:10.1049/ip-a-1.1980.0055

出版商:IEE    

年代:1980

数据来源: IET

摘要:

A miniature capacitance transducer, having a high capacitance and displacement sensitivity, is described. It uses a thin dielectric film on a fixed plate electrode (anodised tantalum), and a variable-area electrode (a gold-coated flexible elastomer dome). An experimental transducer of diameter 7 mm and depth 1 mm has a full-scale capacitance of about 300 pF and a sensitivity of over 2 000 pF/mm.

DOI:10.1049/ip-a-1.1980.0056

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Experiments and theoretical calculations have been performed to determine the conditions necessary to obtain moisture levelling in the drying of beech squares from the green state using radio-frequency heating. The problems investigated include the scatter in final moisture contents owing to anisotropy of the dielectric properties of the wood, inverse moisture content distribution owing to incorrect control of the air temperature, and levelling of the input moisture distribution.

DOI:10.1049/ip-a-1.1980.0057

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Without solving Poisson's (or Laplace's) equation, we use Sylvester's criterion to analyse the conditions for an extremum of electric potential. Particular attention is given to Earnshaw's theorem and to its treatment by various authors. A quantitative demonstration of the theorem is given, and qualitative aspects of unstable points that are, however, relative maxima or minima, are discussed.

DOI:10.1049/ip-a-1.1980.0058

出版商:IEE    

年代:1980

数据来源: IET

摘要:

The Finniston report has led to a re-examination of the education of engineers in this country. The paper examines the state of education in Switzerland for engineers of all grades and makes some comparisons with the current British system.

DOI:10.1049/ip-a-1.1980.0059

出版商:IEE    

年代:1980

数据来源: IET

摘要:

Quality management is not a striving towards perfection but a practical, realistic, objective approach to the achievement of an agreed standard. Quality engineering involves the design of quality systems and the investigation of nonconformance with feedback for corrective action. This can only be achieved by creative interaction with the other functions in a manufacturing unit. Quality engineering is not a narrow specialisation but a broadly based activity which could well lead to general management. With the growth of consumer demand for high quality and reliability, legal requirements for consumer protection and the needs of advanced technology, the importance of the quality function will continue to increase. It must now rank equally with the other functions such as design, production, marketing and sales. All of these functions have an important part to play in achieving quality. A total quality system has been described suitable for a technology and process based industry such as electronic components. This system provides for the continuing improvement of processes, products and quality costs within the unit. There is still scope for further reduction of quality costs as processes with improved capability and control are introduced. This can be achieved with improvement in product performance, conformance and reliability. There is a need to create a greater awareness of the importance of quality improvement at the shop-floor level. Quality circles giving greater responsibility to the shop foreman and increased scope to the production operator and the inspector may be the way forward. The quality management techniques described conform to the requirements of the BS 9000/CECC systems for electronic components of assessed quality. These systems provide broadly based assurance over the complete range of environments for which the component is designed. They are playing a major part in improving electronic components and the benefits are now being seen at the equipment level.

DOI:10.1049/ip-a-1.1980.0060

出版商:IEE    

年代:1980

数据来源: IET

DOI:10.1049/ip-a-1.1980.0061

出版商:IEE    

年代:1980

数据来源: IET