Incorporating weather statistics in determining overhead line ampacity

This paper treats the dependence of overhead line ampacity on weather circumstances. First, the problems associated with too high conductor temperatures (too low conductor clearance to ground, melting of fat causing accelerated aging, and tensile strength reduction) are touched upon. Then the various factors affecting the relation between conductor current on the one hand and conductor temperature on the other is discussed and quantified. Thereafter, a typical conductor used at Essent Netwerk is studied in detail. Using weather statistics for the Netherlands, its ampacity throughout the year is calculated and the derivation of the ampacity value to be used in system planning and operation is discussed. Finally, the relation with system operation and the increase of line ampacity by pinpointing and solving local bottlenecks are discussed.