||Applicable to the conditions of steady-state operation of cables at
all alternating voltages, and direct voltages up to 5 kV, buried
directly in the ground, in ducts, troughs or in steel pipes, both
with and without partial drying-out of the soil, as well as cables
in air. The term "steady state" is intended to mean a continuous
constant current (100 % load factor) just sufficient to produce
asymptotically the maximum conductor temperature, the surrounding
ambient conditions being assumed constant.
Provides formulae for current ratings and losses.
The formulae given are essentially literal and designedly leave open
the selection of certain important parameters. These may be divided
into three groups:
- parameters related to construction of a cable (for example,
thermal resistivity of insulating material) for which representative
values have been selected based on published work;
- parameters related to the surrounding conditions, which may vary
widely, the selection of which depends on the country in which the
cables are used or are to be used;
- parameters which result from an agreement between manufacturer and
user and which involve a margin for security of service (for
example, maximum conductor temperature).
This English-language version is derived from the original bilingual
publication by leaving out all French-language pages. Missing page
numbers correspond to the French-language pages.