Operating capability of ac EHV mixed lines with overhead and cables links

A previous paper has been devoted to the operating capability and constraints involved in power transmission of long AC cable links. In this paper the approach has been extended in order to show the transmission performance of some typical mixed configurations with overhead lines (OHL) and cable lines (UGC). These new capability charts are enhanced with other informative parameters, which allow having a wider knowledge of the regimes of a given mixed line. The necessity of limiting the switching overvoltages during composite line energization, by means of shunt reactive compensation, is investigated and criteria for choosing the compensation degree are also presented.