IEC 61892-4:2019 pdf download

IEC 61892-4:2019 pdf download.Mobile and fixed offshore units – Electrical installations – Part 4: Cables
1 Scope
This part of IEC 61 892 is applicable to the selection of electrical cables intended for fixed electrical systems in mobile and fixed offshore units, including pipeline, pumping or “pigging” stations, compressor stations and single buoy moorings, used in the offshore petroleum industry for drilling, production, accommodation, processing, storage and offloading purposes. This document specifies requirements such as those concerning – types of cables, – voltage rating of cables, – cables and wiring for interconnection of equipment, – current-carrying capacities for continuous service, – correction factors for different ambient temperature and for short time duty, and – short-circuit withstand capacity. This document also gives information on the jet fire test for hydrocarbon (HCF) fire resistant cables. The reference to fixed electrical systems includes those subjected to vibration due to the movement of the unit, for example, cables installed on a drag chain, and not those intended for repeated flexing. This document does not cover flexible cables, for example, those used on drilling decks for top-drive, or cables for portable equipment. This document is applicable for cables with a rated voltage up to and including 1 8/30 kV AC and makes reference to cable standards developed by SC 1 8A. For higher voltages, relevant standards developed by TC 20 are applicable. This document does not apply to – optical fibre cables, – sub-sea and umbilical cables;, – cables supplying downhole pumps, and – data, telecommunication and radio frequency cables.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61 892-1 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 braid armour covering formed from braided metal wires used to protect a cable from external mechanical effects [SOURCE: IEC 60092-350:201 4, 3.3, modified – The notes to entry have been deleted.] 3.2 armour covering consisting of metal tape(s) or wires, generally used to protect the cable from external mechanical effects [SOURCE: IEC 60050-461 :2008, 461 -05-06] 3.3 screen conducting layer or assembly of conducting layers having the function of control of the electric field within the insulation Note 1 to entry: It may also provide smooth surfaces at the boundaries of the insulation and assist in the elimination of spaces at these boundaries [SOURCE: IEC 60050-461 :2008, 461 -03-01 ]
4 Types and operating conditions of cables
4.1 Types of cables Cables constructed in accordance with IEC 60092-353, IEC 60092-354, and IEC 60092-376 shall be used on mobile and fixed offshore units. All cables shall be low smoke and halogen free, using materials according to IEC 60092-360. For voltages higher than 30 kV (nominal), standards from IEC TC 20 shall be used. NOTE 1 Relevant standard from TC 20 is IEC 60840. When cables according to standards from TC 20 are used, the cables shall meet the minimum requirements in IEC 60092-354:201 4, Table 3 “Flame spread tests” and Table 4. In the case of single-core cables for AC systems or cables for circuits with a high content of harmonics, such as SCR circuits, non-magnetic braid armour or armour shall be used. Test requirements for cables exposed to drilling fluid are given in IEC 60092-360:201 4, Annex D. NOTE 2 IEC 60092-350, IEC 60092-353, IEC 60092-354 and IEC 60092-376 specify braid armour only. However, in some countries, cables with armour are also used for offshore applications.U m is chosen to be equal to or greater than the highest voltage of the three-phase system. Where cables are permitted for use on circuits where the nominal system voltage exceeds the rated voltage of the cables, the nominal system voltage shall not exceed the highest system voltage (U m ) of the cable. Careful consideration shall be given to cables subjected to voltage surges associated with highly inductive circuits to ensure that they are of a suitable voltage rating. The choice of standard cables of appropriate voltage designations for particular systems depends upon the system voltage and the system earthing arrangements. The rated voltage of any cable shall not be lower than the nominal voltage of the circuit for which it is used. To facilitate the choice of the cable, the values of U recommended for cables to be used in three-phase systems are listed in Table 1 in which systems are divided into the following three categories.