Expanding upon an existing program to externally inspect the condition of their pad-mounted switchgear, a large investor-owned electric utility in the southeastern United States outsourced the comprehensive internal and external inspection of its entire installed base of 1800 pad-mounted gear units to S&C. Performed with the gear energized, the objective of the inspection program was to develop a prioritized approach to maintenance, which would ultimately extend the life of the gear, reduce outages, and increase system reliability.
S&C’s Power Systems Services personnel worked with the utility to create a customized, detailed inspection list that included the switchgear manufacturer’s inspection procedures, supplemented by the utility’s own practices.
A two-person team of expert S&C field technicians was dedicated to the inspection of all pad-mounted gear on the utility’s distribution system. They coordinated their efforts with the utility’s load dispatchers daily. The crew used the inspection list to record observations and maintenance recommendations for each unit of gear, including conformance with the manufacturer’s installation instructions. Of particular concern were:
- Insufficient terminator-barrier clearance.
- Damaged terminators.
- Gear improperly positioned on its concrete pad.
- Gear with access limited by vegetation
- Missing padlocks.
The crew also developed a prioritization report to identify the switchgear units requiring greatest attention. Gear needing urgent attention was immediately reported to the utility.
In less than a year, S&C inspected all 1800 pad-mounted gear units. While the vast majority of the equipment was manufactured by S&C, the inspection program included an assessment of gear manufactured by other suppliers too. The utility is pleased with the information collected and has expanded the maintenance program to other equipment. They have contracted with S&C for the inspection of 850 pad-mounted transformers serving critical loads. The next round of pad-mounted gear inspections has been scheduled for 2008.