November 18, 2002

Manhole Style S&C Vista^® UDS . . . Just What the Doctor Ordered.

Finding functional switchgear that can squeeze through a manhole opening is an arduous task. Such was the case for one utility in a southern U.S. city. They needed to replace some outdated switchgear and were anxious to avoid the gas leaks they had experienced with SF6-insulated equipment in the past. The new gear was to serve a hospital in a heavily loaded area of the utility’s 15-kV downtown network.

Utility representatives were quite impressed with the Manhole Style Vista Underground Distribution Switchgear they saw at a trade show. This gear features a 630-ampere, three-pole load-interrupter switch or vacuum fault interrupter that’s completely sealed in a rugged stainless-steel tank insulated with SF6. Cable entrance and exit is via 600-ampere bushings or optional 200-ampere bushing wells. The switch operating mechanism has three positions—open, closed, and grounded.

At 15 kV, the tank of Manhole Style Vista UDS is only 29½ inches in diameter . . . fitting easily through the utility’s manhole opening. S&C’s extensive testing of all SF6 gas seals, together with Vista’s field-proven seal integrity, convinced the utility that this switchgear would provide the long service life they sought.

What did they do?

S&C furnished a Manhole Style 15.5-kV Manual Model 110 Vista UDS unit with a load-interrupter switch and 600-ampere bushings.

The Manhole Style Vista UDS is fully submersible. Of three mounting choices — floor, stand, or wall — the utility specified the floor mounted style along with a removable protective lifting frame.

Results

Installation and startup of the switchgear proceeded smoothly, without a lengthy interruption of service to the hospital and other utility customers. The Vista UDS unit continues to function well in its rigorous application.

Contact your local S&C sales office for further details about Manhole Style Vista UDS.