Home>IEC standards>IEC 60183-2015 pdf free

IEC 60183-2015 pdf free

IEC 60183-2015 pdf free.Guidance for the selection of high-voltage A.C. cable systems.
4 Service conditions
4.1 General
To determine the appropriate design of cable system for a particular project, the following information with regard to service conditions is required. Reference should be made to the relevant IEC publications which deal with many of the following service conditions.
4.2 Operating conditions
The following operation conditions apply:
a) Nominal voltage of the system.
b) Highest voltage of the three-phase system.
c) Lightning overvoltage and switching overvoltage for higher (Urn 300 kV) voltage systems (see Table 1).
d) System frequency.
e) Type of earthing and, where the neutral is not effectively earthed, the maximum permitted duration of earth fault conditions on any one occasion and the total duration per year.
f) Screen bonding.
For single-core cables, the current-carrying capability depends largely on the screen bonding technique.
Special bonding (single point bonding or cross-bonding) is generally used where bulk transmission has to be achieved, since the amount of losses in metal screens is significantly reduced, compared to solid bonding (see 2.3 of lEO 60287-1-1:2006). However they require special equipments such as surge voltage limiters (to protect cable sheaths and accessories from transient overvoltages) or earth continuity conductor to be laid along the cable route.
g) Where terminals are specified, the environmental conditions shall be given, for example:
— the altitude above sea level, if above 1 000 m;
— indoor or outdoor installation:
— whether excessive atmospheric pollution is expected: according to IEC TS 60815-1;
— termination in SF6 switchgear; transformer or metal-clad system. with orientation; following IEC 6227 1-209;
— design clearance and insulation used in the method for connecting cable to equipment, for example transformers, switchgear, motors, etc. For example, clearance and surrounding insulation should be specified.
h) Maximum rated current:
— for continuous operation:
— for cyclic operation;
— for emergency or overload operation, if any. without exceeding maximum allowed cable temperature.
A load curve is essential if cyclic loading or emergency or overload operation is considered when determining conductor size.
I) The expected symmetrical and asymmetrical short-circuit currents which may flow In case of short-circuits, both between phases and to earth.
j) Maximum time for which short-circuit currents may flow.
k) Possible operation with forced cooling.
4.3 InstallatIon data
4.3.1 General
The following details apply:
a) Length and profile of route.
b) Details of laying arrangements (e.g. flat or trefoil arrangement) and how the metallic coverings are connected to each other and to earth.
c) Special laying conditions, for example cables in water. Individual installations require special consideration.
4.3.2 Underground cables The following details apply:
a) Typical ambient temperatures over the year (see IEC 60287-3-1).
b) Details of installation conditions (e.g. direct burial, in ducts, mechanical laying, etc.) to enable decisions to be taken on composition of metallic screen or sheath, type of armour (if required) and type of serving, for example anti-corrosion or anti-termite.
c) Depth of laying.
d) Thermal resistivities and kinds of soil along the route (e.g. sand, clay, made-up ground, special backfill). and whether this information is based on measurement and inspection or only assumed. Meteorological data to evaluate risk of soil drying (see IEC 60287 series).
e) Minimum, maximum and average ground temperature at the depth of burial.
f) Proximity of other load-carrying cables (especially where the link involves several parallel circuits) or of other heat sources, with details.
g) Lengths of troughs, ducts or pipe lines, with spacing of manholes, if any.
h) Details of ductbanks, if any: number of ducts or pipes. Internal diameter of ducts and pipes. Spacing between individual ducts and pipes, if more than one. Material of ducts or pipes.
i) Risk for water ingress and corrosion (the right cable design shall be chosen).IEC 60183 pdf download.

Related PowerPoint Templates

Template Categories