Improving protection and control for distribution systems

BY STEVE GREEY, S&C Electric

In 2008, Toronto Hydro completed a study of its worst performing feeders (distribution system feeder lines). This study identified the utility’s distribution feeders with the poorest reliability. The study raised an interesting question: “Why do lateral fuses which, since the 1930s, have been the most effective way of increasing reliability, provide adequate reliability on some of the 27.6-kilovolt distribution feeders and not others?”

In general, lateral fusing has been the most effective way of increasing distribution system reliability for almost 100 years. However, whether or not lateral fuses can meet the reliability expectations of current consumers has become a question.