On-load tap changer diagnosis-an off-line method for detecting degradation and defects: part 2

The following conclusions may be drawn from the material presented above: 1. Dynamic resistance measurements on OLTCs provide early warning of developing faults. They may be used to assign condition indices based on dynamic resistance boundary values. 2. The boundary values can be derived from field measurements, laboratory experiments, and failure investigations. 3. Using a flowchart in conjunction with the dynamic resistance data greatly simplifies the condition index assignment.