IEEE 422-2012 pdf free download – IEEE Guide for the Design and Installation of Cable Systems in Power Generating Stations.
3.1.1 Ambient Temperature. This factor is an important design parameter because it helps determine the continuous current-carrying ca- pability (ampacity) of a cable of a given size in a particular type of installation. In areas where temperatures exceed stated ambient, cables may require ampacity derating and special types of insulation and jacket material.
3.1.2 Current Loading. Power cables should be capable of carrying normal and emergency load currents. IEEE $135 [16] provides cable ampacity tables for various cable constructions and methods of installation. These tables are based on 40 “C ambient air and 20 “C ambient earth and include data for various conductor temperatures. Appropriate factors for cable and conduit grouping are also given, as well as an adjustment formula for change in parameters. Note that the ampacities for cables in under- ground duct banks are based on all power cable ducts being peripherally located and single-con- ductor, nontriplexed, medium-voltage cable shields grounded at one point. (For ampacity derating due to shield currents of medium-volt- age cables with shields grounded at more than one point, refer to 6.1.5.) Ampacities for nonspaced cables in open top trays should be determined from ICEA P-54- 440/NEMA WC51 [ll] rather than from IEEE S135 [16]. Where cables are routed through several types of installation conditions (buried, sun exposure, exposed conduit, covered cable trays, wireways, near hot steam lines, etc), conductor size should be selected for the most severe thermal condi- tion. The application of fire-retardant coverings, penetration fire stops, etc, may affect cable am- pacities and should be considered.
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3.13 Syate.. Fault LeveL Fault cunrnt co pebilitle. of insulated conductor, are given in
ICEA P-32-32 (10).
31.4 Voltage Drop. Voltage regulation requirements should be considered when selecting conductor size Motor f€.d.r voltage drop under starting and running conditions should be urn. tied to allow the motor to operate within its de.ign spedflcaboni
3.1.1 System Nominal Voltage and Groud1ng. Them factors determine the cable voltag, rating and insulation level. ICEA and ARIC standard, see re(erenc.e(1). (2). (10). (13). (121. [13). (141. (15). and 1161) provide guideline. for the proper selection of cabl, rating and inaulation level as well as the overvoltage cop.bilitie. aaeoriated with cable voltage ratings
4. ElectrIcal Segregation of Cable
Systems
flin section provIde. guidance for the electrical segregation of cable systems according to voltage level., signal levels. and vuLnerability to electrical ,iola. pickup.
4.1 Cable Cland&atlons. Medium-voltage power cable, are deeigned to supply power to utilization device. of the plant auxthary systems rated 601-16000 V.
Low voltage power cable, arc designed to supply power to utilization device, of the plant suxiLiary systems rated 600 V or lou.
Control cable, are applied at relatne,ly low current levels or used for intermittent operation to change the operating status of a utilization device of the plant auxiliary system.
Instrumentation cable, are used for trans. mitting variable current or voltage signals (anakgl or Lhcee used for transmitting coded information (digital).
4.2 Segregation Cable. matatled in stacked cm. ble trays generally should be arranged by descending voltage levels with the higher voltage. at the top
4.2.1 Medium-voltage Power Cable.IEEE 422 pdf download.