By Topic

Generation, Transmission and Distribution, IEE Proceedings C

Issue 2 • Date March 1981

Filter Results

Displaying Results 1 - 15 of 15
  • Significance of surface preparation for bolted aluminium joints

    Publication Year: 1981 , Page(s): 45 - 54
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1400 KB)  

    For satisfactory performance of bolted joints using aluminium busbar, particular attention must be paid to preparation of the mating surfaces. The paper describes abrasion tests on aluminium to establish an efficient method. For site use a special wire brush is proposed whereas for factory prepared items, aluminium oxide shot blasting is recommended. The benefit of greasing surfaces prior to clamping has been confirmed. Load-spreading washers are advantageous in ensuring stable joints when allied to good surface-preparation techniques but more specialised clamping arrangements may be necessary if adequate surface treatment cannot be assured. A study of the degradation of alunfinium contacts indicates that the phenomenon of metal-metal adhesion is responsible for maintaining low-resistance joints despite considerable reductions in the clamping load due to creep and differential expansion. The reduction in load does, however, render the joint more susceptible to the effects of temperature cycling and external mechanical forces and this is particularly evident with poorly prepared surfaces View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Z-transform electromagnetic transient analysis of crossbonded cable transmission systems

    Publication Year: 1981 , Page(s): 55 - 62
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (874 KB)  

    A recursive time-domain formulation for electromagnetic transient analysis in power networks has recently been derived drawing on a particular transformation sequence in which the z-transform has a central part. Following its original development primarily in the context of overhead lines, the present paper investigates the possible rÔle of the formulation in transient propagation in crossbonded underground cable systems. In those terms, the earlier z-plane analysis scheme extends easily to the conductor and sheath configuration of a cable section between points of successive sheath discontinuities. It is then shown in the paper, in detailed working, how the boundary conditions of sheath transpositions, sheath earthing, and surge-arrester connections may be introduced into analysis. From the outcome of this working, an overall solution procedure is formulated for a cable system of any arbitrary number of sections in terms of the individual section equations rearranged to comply with the boundary conditions which they are required to fulfil. A Newton-Raphson algorithm is used to solve the nonlinear equations of surge arresters in conjunction with those of the cable sheaths to which they are connected. Close comparisons with solutions from an established Fourier transform method confirm, as in the overhead line case, the high underlying accuracy of z-transform analysis. Computing time requirements have a dependence on the number of sections into which the complete cable system is subdivided: for three sections, z-transform computing times are about 1% of those in Fourier transform analysis View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Surge diverter and transformer nonlinearities in z-transform electromagnetic transient analysis in power systems

    Publication Year: 1981 , Page(s): 63 - 69
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (743 KB)  

    The paper reports developments by which the nonlinear characteristics of surge diverters may be represented in z-transform methods of electromagnetic transient analysis in power-transmission networks. For this purpose, it is shown how surge-diverter equations may be combined with those for network nodes to which surge diverters are connected and solved using a Newton-Raphson sequence. As surge-diverter protection is often associated with transformers, the analysis scheme is then extended to include the nonlinearities of transformer magnetisation characteristics. The analysis method developed is a general and comprehensive one. Within a multinode network formulation, it provides for surge-diverter connections to any number of network nodes, and it allows for any number of transformer branches. In these terms, the work of the paper further advances the recently developed forms of electromagnetic transient analysis in power systems based on the z-transform. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Distribution-system planning using mixed-integer programming

    Publication Year: 1981 , Page(s): 70 - 79
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (995 KB)  

    The prime objective of the study was to develop distribution-system planning models which can be used by distribution-system planners to determine optimum expansion patterns or alternatives by selecting: optimum substation locations, i.e. sites; optimum substation expansions; optimum substation transformer sizes; optimum load transfers between substations and demand centres; and optimum feeder routes and sizes to supply the given loads, i.e. demands, subject to a number of constraints, to minimise the present worth of the total costs involved. The results indicate that the developed optimisation models can be very valuable tools in planning distribution systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on ¿Some practical aspects of overvoltages on the CEGB transmission system¿

    Publication Year: 1981 , Page(s): 80 - 88
    Save to Project icon | PDF file iconPDF (1566 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Editorial. Introduction to special section: Effect of changing safety requirements on nuclear powerstation design

    Publication Year: 1981 , Page(s): 90 - 93
    Save to Project icon | PDF file iconPDF (635 KB)  
    Freely Available from IEEE
  • Licensing and design in a changing environment: a European view

    Publication Year: 1981 , Page(s): 94 - 99
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (928 KB)  

    Some of the factors that contribute to the present extended durations for the design and construction of nuclear power plants are reviewed and an attempt is made to place in perspective the causes for increased project durations over those experienced in the 1960s. The following basic causes are identified: expansion and instability of regulatory activities; increased complexity and scope of engineering design and Increased material quantities and field labor manhours as a result of increased plant size. Experience has demonstrated that all the benefits of scale in plant size have not been realised. With an increase in plant size, it should be expected that the engineering per kilowatt (kW) and the material per kW would drop. Actually there has been an increase which can be attributed primarily to escalations in the regulatory requirements applied to the design. Significant engineering and construction rework has resulted from these escalations during the engineering and construction phases. Industry has been unable to standardise or stabiise its own product and procedures to the extent desired because of this instability in the licensing process and requirements. As a result of this atmosphere of changes and delays, and the growth of administrative controls and surveillance, the productivity of technical and craft personnel has suffered. To measure what could be accomplished to shorten project durations, a basic critical path logic was tested against current experience, a hypothetical case in which there is no licensing process, and a second hypothetical case where previously approved designs were accepted so that the licensing process did not impact the duration. As might be expected, the two hypothetical cases result in essentially identical overall durations. A review of projects designed and constructed under current licensing conditions shows that the licensing process adds approximately three years to the schedule during the capital intesive period after awa- d of the reactor contract. If pre-award extensions due to early planning and site reviews are added to this, the licensing process adds approximately four to five years to a project. The steps toward shortening and improving the confidence in predicting the duration for engineering and construction should proceed in the following sequence: first reasonable stabiisation of the licensing process and requirements for design and construction must be established. Utilities can then depend on this firm base to plan and obtain financing with reasonable assurance that they will meet their objective, and the supporting technical and manufacturing industry can then gear up in a commercially competitive manner with a level of standardisation and methods that would lead to a shorter, more predictable duration for its work. Enforcement of measures to stabiise licensing requirements is thus a prerequisite to shortening project durations and to effective standardisation in the industry View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Nuclear Safety Chains

    Publication Year: 1981 , Page(s): 100 - 107
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1106 KB)  

    An original scheme has been developed for expressing the complex interrelationships associated with the engineered safeguards provided for a nuclear power station. This management tool, based upon network diagrams called Nuclear Safety Chains, looks at the function required of a particular item of safety plant, defines all of the vital supplies and support features necessary for successful operation, and expresses them in visual form, to facilitate analysis and optimisation for operations and maintenance staff. The safety chains are confined to manual schemes at present, although they are designed to be compatible with modern computer techniques. Their usefulness with any routine maintenance planning application on high technology plant is already being appreciated View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quality assurance: is it enough?

    Publication Year: 1981 , Page(s): 108 - 109
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (367 KB)  

    Since 1970, every applicant for a construction permit to build a nuclear power station in the US has been obliged by Federal Regulations to adopt a formal system of QA (quality assurance) for all stages from design to commissioning and operation. Most of those countries which have introduced nuclear power have followed the US lead and many of the international codes and standards are based on those developed by the US. The requirements for formal QA have recently been introduced in the UK in the conditions attached to a site licence. It is therefore an appropriate time to take stock of the position and outline some of the aspects of QA which have to be treated with caution and vigilance, especially as the whole fabric of the US nuclear regulatory system is under severe criticism by the Kemeny Commission, which rightly points out that safety is not brought about just by the `the meeting of narrowly prescribed and complex regulations¿¿ View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on ¿Quality assurance: is it enough?¿

    Publication Year: 1981 , Page(s): 110
    Save to Project icon | PDF file iconPDF (70 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Plant improvements in the prototype fast reactor station at Dounreay

    Publication Year: 1981 , Page(s): 111 - 116
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    The principal features of the prototype fast reactor at Dounreay which were to be proved concerned the reactor and heat exchange systems. The conventional plant was not part of the primary objective of the development programme and was therefore designed at minimal capital costs using limited standby plant. Since the reliability of this conventional system has restricted long-term power generation an improvement programme is included as part of the overall development. Tripping incidents subject the conventional steam plant and reactor to rapid transients. This paper describes plant improvements which have been instigated to reduce, and mitigate such effects. Revised protection and interlocks, controlled power setback and improved feed-water control are part of this strategy. Also the implementation of additional steam dump and condensate bypass facilities increase operating flexibility for heat removal from the reactor. Longer-term decay heat is removed from the sodium by cooling loops and guaranteed cooling fans. The paper describes the improved control for the optimisation of cooling systems to satisfy trip and incident conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Influence of nuclear safety requirements for CEGB gas cooled reactors on the design of their electrical auxiliary systems

    Publication Year: 1981 , Page(s): 117 - 121
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (638 KB)  

    The paper outlines the development of the design of the electrical auxiliary systems at the CEGB gas-cooled reactor nuclear power stations, in response to changes in their requirements with regard to nuclear safety. The changes in system design that have taken place are illustrated by comparing the systems at the earlier Magnox stations with the Advanced Gas-cooled Reactor (AGR) station at Hartlepool. The vital importance of protection against fire is noted, and the stringent fire protection requirements laid down for the later AGR stations are outlined. Further developments in the methods used for electrical auxiliary system design and evaluation, using quantitative analysis techniques, are discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on ¿Influence of nuclear safety requirements for CEGB gas cooled reactors on the design of their electrical auxiliary systems¿

    Publication Year: 1981
    Save to Project icon | PDF file iconPDF (173 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electrical system design for future AGR power stations

    Publication Year: 1981 , Page(s): 123 - 128
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (931 KB)  

    The necessity to cool a reactor safely after it is tripped has always made the heaviest safety demands on the electrical system, independent of reactor type. In earlier gas-cooled reactor stations sufficient essential plant was provided to cope with the maximum breach which could credibly occur in the reactor pressure circuit, with a spare plant allowance to cover maintenance and fault outage assuming loss of grid at this time. Now, cooling plant is designed to meet reliability criteria. To make sure it does this, its performance is examined systematically, over the range of possible faults, and its failure modes analysed. These modes include random and common-mode component failure, in combination with hazards such as high winds, earthquakes, fires or turbine disintegration. To safeguard the cooling function in such circumstances it has been necessary to subdivide the essential electrical plant and its associated mechanical drives into functionally independent subsystems, called trains. Because the changed safety requirements have involved more plant, more widely separated, they have increased costs. Such cost increases have been minimised by balancing the risks over the systems, integrating electrical and mechanical plant layout in the reactor buildings, and reducing the size of the essential prime movers. This size reduction has been made possible by interposing frequency converters between them and the largest (gas circulator) drives. Expensive site fitting is reduced and the possibility of fouls, or failures to segregate is avoided by means of a comprehensive (1:20) scale model View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on ¿Electrical system design for future AGR power stations¿

    Publication Year: 1981 , Page(s): 128
    Save to Project icon | PDF file iconPDF (203 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.