Thermal capacity of collector system feeders in wind farms

The thermal capacity of a collector system feeder in a wind farm is determined by the maximum temperature allowed by the cable insulation. There are locations within the collector system where the cable ampacity is lower due to a higher thermal stress. Based on the latest edition of the NFPA70 and CSA22.1, these locations could become the driving factor in the selection of the cable size during the design of the collector system. Hence, the design efforts can be substantially reduced by concentrating the analysis on those specific locations. Furthermore, by decreasing the thermal stress in those areas, it is possible to reduce the size of the feeders for the entire collector system. This study presents the analysis of the thermal stress in collector system feeders, showing with examples, how the ampacity of the cable is substantially reduced when the limits specified by the codes are considered.