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Limitations of the Ruling Span Method for Overhead Line Conductors at High Operatring Temperatures
(1998)
Аннотация
This report summarises the work by the Task Force
to review the accuracy of the ruling span method for
conductors operated at high temperatures, The basics of the
ruling span approximation method have been examined, The
traditional ruling span approach can be used with little or no
error for a typical overhead line crossing a rolling terrain to
predict sags in suspension spans for conductor operating
temperatures in the range of 50°C to 70°C. It was confirmed
that the ruling span method is the most practical way to string
conductors in multi-span line sections. Sensitivity studies were
Merformed using conductors "Lapwing" and "Tern" in order to
91uantify such ruling span assumptions as the effect of the
longitudinal swing of suspension and line post insulators on
conductor sags at high temperatures, and the effect of the
suspension insulator string length on the equalization of
conductor tensions in adjacent spans. Significant errors in
estimating the sag at conductor temperature above 100°C may
occur if the tension differences are not taken into consideration
in line sections consisting of a series of spans of non-equal
lengths.
