“Hy-therm” copper — An improved conductor

THE SIZE of conductors for overhead lines generally has been selected on the basis of obtaining the required voltage regulation and most economical power loss. Usually, these criteria result in a larger size than would be necessary from a thermal limitation. However, there have been many instances, such as in short tie lines, where it has been necessary or desirable to load the conductors to their thermal limit. For this reason there has been a continuing interest in the determination of both the maximum continuous and short-time emergency overload capabilities of the conductors. Insufficient data on the annealing characteristic of copper prevented the establishment of uniformly acceptable limits.