Ralph Donati ABB Electrification Installation Products Memphis, USA ralph.donati@us.abb.com
Elastimold™ switchgear proved to be exactly what Greystone needed.
GreyStone Power Corporation, a large electrical cooperative near Atlanta, Georgia, was seeking an “oil-less” retrofit solution for its oil-insulated switchgear installed base to alleviate concerns of potential leaks, maintenance costs, and downtime inherent to owning oil-insulated pad-mounted switchgear. In addition, GreyStone was looking for a switchgear solution that would be easy to retrofit in the field with a minimum amount of labor. To accommodate this, the retrofit solution needed to fit onto the existing pad, have matching phase rotation, and eliminate the need to splice or pull in new cable.
Elastimold™ switchgear, which is available from ABB, proved to be exactly what GreyStone needed. A completely solid dielectric line of switchgear, Elastimold has two main components that are the core of its product offering – a molded vacuum switch (MVS) and a molded vacuum interrupter (MVI). Both devices are available with user-specified IEEE 386 underground interfaces such as 200A load break bushing wells and/or 600A dead break bushings.
Switchgear configurations typically use MVSs with 600A on the source side for load switching. MVIs are more common on the load ways for fault interrupting and sectionalizing. Using the modularity and operational flexibility of MVSs and MVIs, ABB’s engineers were able to develop a custom retrofit switchgear for GreyStone. Due to the small and compact nature of its MVSs and MVIs, Elastimold switchgear typically has a smaller overall footprint compared to other switchgear with different insulation technologies. However, for this project, the Elastimold design used a larger than standard cabinet to match the same dimensions as the original switchgear, allowing it to be placed onto the existing pad. Using a cable bus, the Elastimold™ retrofit switchgear was able to replicate the original switchgear’s phase rotation of ABC-CBA.
Elastimold solid-dielectric molded vacuum switches, interrupters and switchgear are now available with the Tru-Break™ switchgear module that makes it easy for linemen to switch the handle to the open position and visually verify the isolating gap in the conducting path. The small window in its design has contributed to safer installation. Knowing with certainty that the circuit is open, linemen can safely ground a line and perform maintenance on a de-energized, isolated and grounded circuit.
The product’s modular design offers the important advantage of enabling an economical retrofit of the Tru-Break switchgear module to previously installed Elastimold single-phase and three-phase switchgear. It took GreyStone approximately 2 hours for a complete retrofit rather than an estimated 8 hours from their experience with a non-custom “oil-less” solution.
