A new probabilistic approach to thermal rating overhead line conductors evaluation in the Netherlands

It is common practice among electric utilities to assess the nominal current ratings of overhead lines for power transmission and distribution by means of the deterministic method. This approach is only applicable to stationary situations, in which a set of fixed values for the worst combination of meteorological parameters and the design maximum conductor temperature have been assumed. However, by means of statistical modelling methods it is possible, on the basis of the expected load distribution, to determine the probabilities of exceeding the critical conductor temperatures. The research carried out so far is aimed at determining the conductor temperature distribution and estimating the possible consequences for the lifespan of the overhead conductor