Jeffrey E. Shield
Date of this Version
Weyer, Daniel. "Material Evaluation: Self Damping Wire SD/ACSR Conductor Failures." Thesis, University of Nebraska - Lincoln, 2016.
Material Evaluation: Self Damping Wire
SD/ACSR Conductor Failures
Following numerous 954 ACSR SD Wire failures from 2010 to 2012, Nebraska Public Power District (NPPD) implemented an inspection program to determine the extent of condition for this type of widely used conductor. NPPD transmission system includes over 2000 miles of this particular conductor.
Transmission line splices are installed every 15-20 spans, with failures being located in a span containing a splice. NPPD worked with Kinectrics to complete electromagnetic field inspections for three days in 2013, with retesting performed in 2015. Throughout this inspection of 54 spans of conductor, 36 were found to have deterioration and corrosion.
Over 80% of the corrosion noted in the report was found on a conductor span containing a splice; only 45% of the spans tested contain a splice. All of the failures occurred in spans where a compression sleeve or compression dead-end was present. In all cases, only the steel core broke internal to trapezoidal aluminum wire layers. The results of the inspection indicated that there is a notable amount corrosion located in the few hundred feet at the center of the span.
Removal of spans testing “marginal” occurred in April 2015, along with the physical evaluation of the conductor validating the results of the electromagnetic inspection tool. None of the conductors were rated as poor, which would indicate no imminent failures exist. Since none of these localized areas were in poor condition, it could be several years before more frequent findings of broken wire and related problems are observed.
Advisor: Jeffrey E. Shield