The Dynamic Duo

Ultrasound inspection and infrared imaging

Gerdau, based in Brazil, is one of the world’s largest steel producers and trades on the New York Stock Exchange under the symbol GNA. Gerdau Ameristeel is the American branch of Gerdau Brazil and has 19 mills across North America. The majority, if not all, of Gerdau’s mills use various predictive technologies to keep electrical outages to a minimum.

Skip Young, a certified infrared and ultrasound technician at Gerdau Ameristeel in Calvert City, KY, provided a good example of how combined predictive inspections prevented a transformer outage.

Electrical faults usually only generate heat once they’ve reached an advanced stage. Relying solely on Infrared (IR) may result in a missed diagnosis, but not for Skip Young. He brings his ultrasound detector with him to all scheduled IR scans. He understands that acoustic energy is produced at any stage of discharge, and that by combining ultrasonic and infrared scans, he is assured to find virtually all faults.

The insulator shown in Figure 1 was damaged by tracking, and eventually, arcing. With the use of an ultrasound inspection equipment, the problem was discovered early on. In fact, electricity always follows the easiest path to the ground, therefore, dirt, dust, and moisture make it easier for tracking to establish a path to the ground. Tracking indicates the presence of an equipment failure, which may often be repaired with easy maintenance procedures if identified early enough.

All inspectors performing this work must consider the serious safety implications.