Medium-voltage switching and protection equipment doesn’t need to be complicated. Manual Vista Underground Distribution Switchgear is purpose-built to simplify operations while providing an intuitive solution to managing complex medium-voltage power-delivery needs.

S&C Remote Supervisory Vista Underground Distribution Switchgear provides automated switching and fault protection and — when applied in S&C’s High-Speed Fault-Clearing System — can also perform auto-sectionalizing without tripping the main breaker. It incorporates the same outstanding features as Manual Vista Switchgear and can be specified with a communication and control equipment group, for a completely integrated, self-powered switching and protection package.

• Your choice of remote terminal unit, including S&C’s 6800 Series Automatic Switch Controls. These sophisticated controls support S&C’s self-healing, scalable IntelliTeam® SG Automatic Restoration System — a universal Smart Grid solution offering unmatched interoperability.
• Your choice of communication platform or device, including fiber optics or S&C’s SpeedNet™ Radio.
• Motor operators provide three-second operation of load-interrupter switch ways and three-pole group-operated fault interrupter ways. They’re easily moved between ways . . . no reconfiguration necessary.
• Three-phase current sensing and line-to-ground voltage sensing for every motor-operated way.

Each S&C Source-Transfer Vista Underground Distribution Switchgear unit provides fully automatic primary-selective service and fault protection for one, two, or three critical load circuits. This Smart Grid solution incorporates the same outstanding features as Manual Vista Switchgear, plus S&C’s Micro-AT^® Source-Transfer Control, motor operators, three-phase voltage sensing on source ways, and voltage transformers for control power. It's available in common-bus and split-bus configurations. Furnished in ratings through 38 kV, Source-Transfer Vista Underground Distribution Switchgear features carefully integrated components that ensure compatibility — all factory-assembled and checked-out.

For larger or more complex source transfer systems, multiple Source-Transfer Vista Underground Distribution Switchgear units equipped with Micro-AT Source Transfer Control or 6802 Automatic Switch Control can handle any number of sources and critical loads.

• Micro-AT Source-Transfer Control offers self-healing response to distribution system problems. Transfers on loss of source, voltage unbalance, or any source-side open-phase condition. It’s easy to set up . . . all settings are keypad-programmable, calibration is automatic. Optional overcurrent-lockout feature prevents automatic transfer operation that would close a source load-interrupter switch into a fault. Optional communications card lets you rapidly upload event log to your PC, download standard settings.
• Motor operators on load-interrupter switch ways provide automatic switching between the sources. Also provide automatic operation of bus-tie switch in split-bus configuration gear.
• Three-phase voltage sensing for each source. Three-phase current sensing furnished too when optional overcurrent-lockout feature is specified.
• Self-powered by voltage transformers.
• Exceptionally rugged enclosure construction and the industry’s finest finish. Provides extraordinary resistance to the elements, keep high-voltage components securely isolated from unauthorized access.

S&C Vista Underground Distribution Switchgear models with 15-kV loadbreak switches rated 40 kA symmetrical short time are an ideal fit for sectionalizing underground distribution networks. Switchgear in urban areas is frequently installed subsurface or in street or sidewalk vaults, so a compact size is generally required along with an ability to withstand routine flooding. Available fault-current levels also may be very high and exceed the capabilities of most compact and submersible switchgear. Few switchgear products offer all the capabilities needed to perform reliably under such difficult conditions.

S&C’s Vista Underground Distribution Switchgear offers a superior solution for adding switching points to urban distribution networks. Our 15.5-kV Vista Switchgear models incorporating loadbreak switches with a momentary rating of 40 kA symmetrical provide all the features needed for vault and subsurface switching applications, including a fully submersible design that offers reliable performance even in vaults prone to flooding. Vista Underground Distribution Switchgear is gas-insulated, eliminating the maintenance and safety concerns associated with oil-insulated switchgear. And, unlike lower-rated switchgear, it eliminates the need to incorporate current-limiting devices, which are difficult to coordinate and increase operating complexity.

Compact Pad-Mounted Style Vista Switchgear improves aesthetics and reduces real-estate requirements — especially at 34.5 kV, where air-insulated gear is too large to be practical in many applications.

• Compact footprint and low profile — Pad-mounted enclosures feature hinged roofs and removable panels, providing convenient access to both the operating and termination components
• All cable terminations are located on one side of the gear. Minimizes operating clearances, reduces space requirements. A typical 15-kV Vista installation requires just 1/3 the space of conventional pad-mounted gear
• A single Vista unit accommodates up to six load-interrupter switches, fault interrupters, or combination of each. So more loads can be served from a single unit. Eliminates need for redundant switches and extra cabling, trenching, and box pads — and additional operating clearances needed between multiple units
• Operating controls are isolated from the cable compartment. Thanks to Vista’s innovative features, operating personnel are never exposed to medium-voltage during routine operations.
• Certified arc resistant per IEC 60298 Annex AA for fault currents up to 25kA symmetrical for 15 cycles . . . adds another level of safety for operating personnel.

Underground and out of sight — yet easy to operate from ground level — unique submersible UnderCover Style Vista Switchgear is ideal where aesthetics are extremely important, or where space limitations make it difficult to site gear above ground.

• Gear can be installed exactly where it’s needed, reducing the costs associated with trenching and unnecessarily long cable runs
• All operating controls are located on top of the gear, easily accessible from ground level — and isolated from medium-voltage cables
• Integral “closed-open-grounded” positions on every switch and fault interrupter allow easy isolation and grounding of cables with no exposure to medium voltage
• One person, standing above grade, can easily perform all routine operations without handling cables or entering the underground vault
• Eliminates added time and complication of entering a confined space
• Certified arc resistant per IEC 60298 Annex AA for fault currents up to 25kA symmetrical for 15 cycles . . . adds another level of safety for operating personnel.

Vista Switchgear in the Vault Mounted Style provides a compact switching and protection solution for manholes, electrical rooms, and sidewalk vaults, where space is extremely limited. A single unit accommodates up to six load-interrupter switches, fault interrupters, or combination of each.

• Wet-vault-mounted style features a stainless-steel tank and fully submersible wiring, perfect for manholes and other harsh environments
• Dry-vault-mounted style is ideal for electrical rooms and vaults that aren't subject to flooding
• Optional portable motor operator with 50-foot cord and remote control lets you perform switching outside the vault or in an adjacent room
• Operating controls are located away from cables. Personnel are never exposed to medium voltage during routine operations. Cable handling — particularly awkward in vaults — isn't necessary

Wind Turbine Style Vista Switchgear is a slim, single-way three-phase version that’s typically applied in wind turbine towers. It can fit through the typical 24-inch wide opening of the turbine door, and provides connection and switching points for the medium-voltage cables from the generator output. It’s generally specified with resettable fault interrupters, but can also accommodate load-interrupter switches.

Wind-Turbine Style Vista Switchgear can be positioned along the inside wall of the tower, providing more space for personnel and equipment.

Manhole Style Vista Switchgear is a round, single-way, three-phase version that’s typically installed through the manhole access opening of an underground vault. It features either a load-interrupter switch or vacuum fault interrupter, sealed in a rugged, stainless-steel SF6-insulated tank. Cable entrance and exit is via 600-ampere bushings or, optionally, 200-ampere bushing wells.

An optional voltage indicator lifts to expose a large viewing window, allowing a clear view of the switch, open gap, and gas pressure indicator. Manhole Style Vista Switchgear is fully submersible, and can be mounted on the floor, stand, or wall.

Developed for the U.S. military, small, lightweight Mobile Heavy-Duty Style Vista Switchgear is specially designed to withstand the rigors of extended air transport at high altitude. Gear stacked two-high (to conserve space aboard an airplane) has passed the MIL Spec E-810 20-hour shaker-table vibration test, verifying that it can withstand 10,000 miles of air travel, and that performance is not affected by the low atmospheric pressure experienced during transport at an altitude of 40,000 feet.

This unique version of Vista gear is suitable for temporary or permanent installations. Comprised of two load-interrupter switch ways and four fault-interrupter ways, it features an enclosure frame and integral skid constructed from heavy-duty I-beams and channels. Eyebolts and alignment pins on the top facilitate lifting and stacking. Turnbuckles, attached to eyebolts on the front and rear sides of the skid, hold the stacked units together during transport. Channels on the bottom allow forklift handling. Reinforced tabs on the skid allow the gear to be dragged along the ground. Plates, attached to the floor of the enclosure, protect the switchgear during transport and storage and can be removed to facilitate cable entry.

Vista Switchgear is suitable for a variety of “special” applications. For example, when an existing conventional metal-enclosed switchgear lineup needed to be expanded to accommodate two additional feeders — but there was only room for one more bay — a new special bay was constructed externally matching the others, containing a unit of Vista gear.

SF6-insulated Vista gear is much smaller than conventional air-insulated metal-enclosed gear. A typical 25-kV conventional metal-enclosed switchgear feeder bay is about 52 inches wide; the two bays required for this application thus would be 104 inches wide. But the three-way Vista UDS unit housed inside the special bay is only 58 inches wide, reducing the space requirement by almost half.

The Vista gear is operated from a control panel that’s completely isolated from medium-voltage components. The position of each fault-interrupter disconnect — open, closed, or grounded — is easily seen through large viewing windows. With the disconnect in full view, operating personnel can verify the open gap and ground cables without having to remove elbows or T-bodies. And by using the optional push-button voltage indicator furnished, they can check voltage without moving cables. A door at the rear of the bay allows access to the elbow connectors.

Refer to Specification Bulletins 681-31, 681-32, 682-31 and 683-31 for more details.

Refer to Specification Bulletin 695-33 for more details.