Is there a correlation between compression connectors — a two-stage full-tension compression joint, or splice, and a two-stage compression dead-end — and corrosion in aluminum conductor steel-reinforced self-damping conductors? Nebraska Public Power District (NPPD) asked this question a few years ago after discovering some steel core wire breaks during annual line patrols.

Between September 2010 and June 2012, NPPD found six steel core failures on conductors that had been in service for 30 to 40 years; another failure occurred in April 2015. All instances involved a 954-kcmil aluminum conductor steel-reinforced self-damping (ACSR/SD) Type 7 conductor on different long spans in high-voltage transmission lines. All failures occurred in spans where either a splice or a dead-end was present and only the steel core was broken.

These failures indicated a possible relationship between splices/dead-ends and corrosion. It was unknown whether other factors such as the relationship of the corrosion with conductor motion, atmospheric condition, topography and geographical location could have contributed to the failures.

NPPD, conductor corrosion
When all corrosion locations are plotted for non-dead-end spans, 30 of 33 locations (91%) are within 150 ft of the low point of the span.