Case Study

Identifying Manufacturing Issues with Factory Grade® Technology

Manufacturing Molding Issue Identified with IMCORP Factory Grade® Technology

OVERVIEW
Manufacturing molding issues and workmanship issues are identified with the Factory Grade® technology.
CHALLENGE
Identifying root cause of substandard performance of premolded dead-front Tbodies in an efficient and effective manner.
RESULTS
Utility client partners with IMCORP to ensure quality and educate installers on how to identify manufacturing defects with immediate, evidencebased feedback before failure

After days of unproductive effort, a utility could not locate the failures caused by a destructive VLF (Very Low Frequency) test and the energization window was closing for the new cable system feeding a critical industrial customer. The utility asked IMCORP to help. The initial assessment with our Factory Grade® technology pinpointed three pre-molded 750kcmil T-body style terminations in two different locations which showed evidence of insulation ruptures. The T-bodies were installed in a ‘hammerhead’ configuration with two 750kcmil T-bodies connected to either end of a 1000kcmil T-body. In additional to locating the multiple fault locations, the IMCORP Factory Grade® assessment also identified multiple 1000kcmil hammerheaded Tbodies that were failing to meet the manufacturer’s minimum performance standards. With agreement from the utility and the manufacturer, the three faulted 750kcmil and 1000kcmil T-body sets and an additional 1000kcmil Tbody exhibiting substandard performance were sent to IMCORP’s lab for dissection and root cause analysis.  
 
Based on the evidence received, all the 750kcmil T-bodies showed anomalies in the inner surface in line with the top mold fill ports. The substandard performance for the 1000kcmil T-bodies was likely due to workmanship issues at the cable cutbacks (non-radial and jagged cutbacks, knife cuts/gouges) in the cable insulation. The molding issue was later verified by the manufacturer, who took the appropriate corrective actions. Our Factory Grade® technology then verified the entire cable system met the manufacturer’s performance standards. The case is yet another example of IMCORP partnering with utility clients to ensure quality and educate installers on how to identify defects with immediate evidence-based feedback before failure.
Figure 1: Anomaly found inside surface at the mold injection port one of the unfaulted 750kcmil T-bodies (left picture, yellow circle).  The anomaly appeared to be  a U-shape crack completely penetrating the semiconducting material (Faraday cage). Note the damage/crack continued into the insulation material but had not failed yet.

 

LEADERSHIP

THE STANDARD IN POWER CABLE RELIABILITY