Analysis on Temperature Dependency of Effective AC Conductor Resistance of Underground Cables for Dynamic Line Ratings in Smart Grids

As intermittent renewable energy resources increase in smart grids, transmission cable overload is a significant problem. Dynamic line rating is one of the promising technologies and usually involves analysis via a thermal equivalent circuit model. This paper analyzes the temperature dependency of the effective AC conductor resistance of power cables to represent the heat generation more precisely at the conductor for the thermal equivalent circuit model. Next, the insulation layer is partitioned into several subcomponents to represent the heat transfer more precisely from the conductor to the outside surface due to fast and large line-current variation. Finally, this study evaluates various cases of conductor temperature evolutions for a step change in line current due to the N-1 contingency situation.