The North American Electric Reliability Corporation (NERC) has become aware(2010) of discrepancies between the design and actual field conditions of transmission facilities including transmission conductors. These discrepancies may be both significant and widespread, with the potential to result in discrepancies in line ratings.
NERC has recommended, Not enforced but asked to report the status of actions regarding this recommendation, to all registered entities with generator tie lines, radial transmission lines and interconnection facilities.
In this case, in the pic; conductor ground clearances have been analyzed and improved in compliance with NERC requirements:
-Suspension insulator assemblies have been converted to floating dead-ends.
-Conductors re-tensioning have been performed in other cases.
Other options considered: taller structures installation, vegetation management.
Worst case scenario: Line derating consistent with actual field condition.
