Bolometer detection of line temperature rise

THE LOCATION of high-resistance transmission line joints on circuits long in service has been an almost routine procedure of many utilities for some time past. Considerable effort has been expended by The Hydro-Electric Power Commission of Ontario in making such measurements. Many of the circuits, of aluminum cable steel-reinforced (ACSR) construction, are now over 25 years old. Bearing in mind the limited knowledge of techniques for joining aluminum conductors which existed at that time, it is not surprising that some conductor joints began failing after a useful life of 25 or 30 years. The seriousness of such failures regarding danger to life and interruption of service is apparent.