Introduction: Three windfarms are to be connected at 33kV to East Kilbride South 275/33kV substation in an area where there is significant windfarm activity. In order to minimise costs the three cable connections will share a common trench for the initial 10.7km length from the substation. This shared cable route has been influenced by the need to ensure thermal independence from an existing adjacent 275kV cable that supplies Whitelee Windfarm. Each windfarm cable connection is made up of three single core cables laid up in trefoil. Given the close proximity of the three 33kV windfarm cable circuits each has been de-rated to 32.2MW.

Two of the three windfarm developers have subsequently asked about the prospect of increasing their generation capacity in the future and if any spare head room capacity might be available.

The installation offers a rare opportunity to consider the dynamic ratings for three parallel adjacent cable circuits and the prospect for a future trial of active network management for Distributed Generation (DG), with a view to accommodating further renewable generation without network reinforcement.

Objectives: The project aims to establish dynamic cable ratings for three cable circuits (3 - 33kV) and assess the impact the renewable generation from the three windfarms will have on these circuits. From this analysis the prospect of further network capacity being available will be determined.

This project will help inform future cable rating calculations for other projects which could negate or postpone the requirement for upgrading or reinforcing the distribution system.