Tips & News - September 2012

Migrating to USCO ® Center BreakV Switches: Problems and Solutions Technical Support Assists with Customer Switch Transition By Juan Gutierrez, Jr., Senior Engineer Arizona Public Service (APS) Yuma, Arizona

For over 25 years, Arizona Public Service (APS) used Cooper Power Systems (formerly KPF) air break switches on our 69-kV overhead transmission lines. The switches are rated for 900- A, which worked well for us, since APS used 795 all-aluminum conductors on our transmission lines with the average amperage of about 850-A.

In 2009, APS began designing lines that could carry more current. The operation/planners began looking for ways to carry more current over our existing lines; therefore, we started reconductoring existing lines with 795 ACSS conductors, which can carry currents as high as 1500-A. Since the Cooper/ KPF air break switch was rated for 900-A, it was no longer an option. APS’ T&D Engineering and Standards (TDES) began looking at higher-rated air break switches and contacted a Hubbell representative for more information on the USCO® Center Break V Switch. This switch could withstand currents as high as 2000-A, but it was a different kind of switch and our APS construction and maintenance crews had reservations.

www.hubbellpowersystems.com

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