Hybrid lines comprising overhead line sections and underground cable sections are becoming more common, especially in urban areas. Many faults on overhead sections are transient faults, and automatic reclosing for these faults would have considerable system reliability benefits. However, reclosing for permanent faults in cable sections is counterproductive and would increase the damage and drive up the cost of subsequent repairs. Until now, our industry has not had an economical solution to the challenge of autoreclosing on hybrid lines. Therefore, autoreclosing is typically not applied on hybrid lines, hurting power system reliability and power quality and discouraging utilities from building hybrid lines in the first place.
Double-ended fault locating based on current traveling waves (TWs) is very accurate on hybrid lines. Calculated in hard real time, TW-based accurate fault locating allows you to control your autorecloser, providing a cost-effective autoreclosing control solution for hybrid lines.
Watch Dr. Bogdan Kasztenny, SEL protection engineer, discuss these industry-challenging topics.