Electrical faults in the power system

Electrical faults in the power system • Transmission lines 85% • Busbar 12% • Transformer/ Generator 3% Classification of Faults: Transient faults: A transient fault is a fault that is no longer present if power is disconnected for a short time. – are common on transmission lines, approximately 80-85% – lightnings are the most common reason – can also be caused by birds, falling trees, swinging lines etc. Persistent faults: A persistent fault does not disappear when power is disconnected. – can be caused by a broken conductor fallen down – can be a tree falling on a line – must be located and repaired before normal service