The Difference between Transient & Permanent Faults

Transient Fault

• Transient faults are those that disappear when power is interrupted and then restored.
• Often caused by occurrences like lightning, momentary tree contact, or contact with animals.
• In such cases, the line can be successfully re-closed after it's been tripped.

Source: A.A.Z. Zin, S.P.A. Karim, The application of fault signature analysis in Tenaga Nasional Berhad Malaysia

Permanent Fault

• Permanent faults persist even when power is restored.
• These faults stem from prolonged issues such as tree or crane encroachment, insulation breakdown, tower collapse, or cable damage.
• Reclosing the line fails because the fault persists during the attempt to restore it.

Source: A.A.Z. Zin, S.P.A. Karim, The application of fault signature analysis in Tenaga Nasional Berhad Malaysia