The calculation of cyclic rating factors for cables laid direct or in ducts

Goldenberg, Harry

doi:10.1049/pi-c.1957.0018

Cited by 7 publications

(9 citation statements)

References 6 publications

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“…A point to note is that, by neglecting the effect of the thermal capacity of the cable, the conductor temperature is somewhat overestimated, 12 and hence the corresponding overloads or cyclic rating factors are somewhat underestimated or on the safe side. Eqn.…”

Section: )mentioning

confidence: 99%

“…This procedure for ducts is on the safe side. Tabulated values of k have been published 12 for certain standard British cables 24 for which the dielectric loss is negligible. Alternatively, 12 k may be directly related to the cable losses per unit length.…”

Section: )mentioning

confidence: 99%

“…If the simpler load is a step function, the square of the applied cyclic current is approximated by an equivalent curve of rectangular steps with approximately the same mean. 12 If the simpler load is sinusoidal, Fourier analysis is used. 25 " 27 The difficulty with the direct application of either of these methods is the amount of calculation involved.…”

Section: Cyclic Loadingmentioning

confidence: 99%

“…A limitation with the use of the method was that the tabular values related to fixed thermal diffusivities of 0 01 and 0 02cm 2 /s, and to a fixed depth of burial of 36 in, and it was generally not a simple matter to deal with other values for these parameters. This limitation has subsequently been overcome by the use of a computer program, 34 permitting the calculation of new tables for any values of the parameters concerned. The cable-surface attainment factor may be specified by either the WhiteheadHutchings formula or the exponential-integral formula, for use in this program.…”

Section: Cyclic Loadingmentioning

confidence: 99%

“…Tables have been given for this method, with the same restriction on parameters as for the previous method. This limitation has been removed by the use of a second computer program, 34 for which the parameters may be chosen at will and for which the cable-surface-attainment-factor formula may be specified as either the Whitehead-Hutchings formula or the exponential-integral formula.…”

Section: Cyclic Loadingmentioning

confidence: 99%

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Transient heating of buried power cables

Goldenberg

1967

Proc. Inst. Electr. Eng. UK

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SynopsisAn account is given of past work in the field of thermal transients in buried cables. From the publications of Morello and Van Wormer, it follows that the earliest simplified theoretical formulas for the conductor transient, produced for application to small-diameter cables, can be correct only for times sufficiently large for the effect of the thermal capacity of the cable to be negligible. For such large times, the simple exponentialintegral formula is shown to give a cable-surface attainment factor that is closer to the solution of the proposed model of Whitehead and Hutchings than is the more complicated Whitehead-Hutchings formula itself, although the difference is generally negligible. A comparison is given between the cable-surface attainment factor based on a constant rate of heat flow from the cable to the soil, and the corresponding exponential-integral formula.

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Section: )mentioning

confidence: 99%

Section: )mentioning

confidence: 99%

Section: Cyclic Loadingmentioning

confidence: 99%

Section: Cyclic Loadingmentioning

confidence: 99%

Section: Cyclic Loadingmentioning

confidence: 99%

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Transient heating of buried power cables

Goldenberg

1967

Proc. Inst. Electr. Eng. UK

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Optimal placement of underground cables to maximise total ampacity considering cable lifetime

Zarchi

Vahidi

2016

IET Generation, Transmission & Distribution

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Natural and forced-cooling of HV underground cables: UK practice

Williams

1982

IEE Proc. A Phys. Sci. Meas. Instrum. Manage. Educ. Rev. UK

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The paper reviews the progress of the various forms of cable cooling systems that have been developed for the UK CEGB's major high-voltage transmission network. The generation and transmission system in the UK prior to the establishment of the 132kV grid is discussed, together with the reasons for building the higher-voltage network. The statutory duties of the CEGB and its transmission responsibilities are outlined, special reference being made to the undergrounding of part of the network for amenity reasons. The investigations of soil properties, their effect on cable ratings and the subsequent adoption of standardised thermal resistivity and temperature values are considered, together with the development of special backfill materials. The different types of forced cooling system are discussed: separate water-pipe, trough and weir, air, integrally and internally cooled methods being covered comprehensively. Rating limitations caused by cable joints, and the methods used to overcome them, are included. Cooling stations and the plant and control equipment installed therein are described, reference being made to the different sources of coolant, e.g. air, borehole water, river or lake water etc. A brief description of the computer methods of solving the complex equations derived for forced cooling installations, using thermal image, finite difference, finite element and analytical techniques, is given. The Appendix comprises three Tables, giving the essential design details of naturally cooled, separate-pipe water-cooled and tunnel systems installed on the CEGB's transmission system.

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The calculation of cyclic rating factors for cables laid direct or in ducts

Cited by 7 publications

References 6 publications

Transient heating of buried power cables

Transient heating of buried power cables

Optimal placement of underground cables to maximise total ampacity considering cable lifetime

Natural and forced-cooling of HV underground cables: UK practice

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