How many monitors should be used in order to calculate the dynamic thermal rating of an overhead line?
Weather conditions vary with time and distance. Air temperature and solar heating are reasonably consistent spatially and according to time of day. Wind is highly variable with both distance and time. For sag-based ratings, it is sufficient to monitor at one location per ruling span. For several tandem ruling spans in the same terrain and having the same direction, monitoring of one span may be sufficient.
