Vista® Underground Distribution Switchgear

S&C Vista Underground Distribution Switchgear, available in ratings through 38 kV, features elbow-connected components enclosed in a compact, submersible, SF6-insulated, welded-steel tank, completely protected from the environment.

Vista gear is offered in four styles—the innovative UnderCoverTM style, as well as pad-mounted, vault-mounted, and manhole styles. Manual, source-transfer, and remote supervisory versions are available. All models use the same basic components, cutting your operator-training and inventory costs.

Construction details of source-transfer and remote supervisory models are shown on pages 20 and 21.

Handles More Loads Per Unit

Vista gear is furnished with up to six “ways” per unit, each consisting of:

• Bus terminals;
• A load-interrupter switch for switching 900-A main feeders; or
• A microprocessor-controlled, resettable arc-spinner or vacuum fault interrupter for switching and protecting 900-A main feeders and 600-A or 200-A taps, laterals, and subloops.
  By handling more loads per unit, you need fewer units, saving you money.

Place Gear Just Where It’s Needed

Vista gear is submersible and considerably smaller than traditional air-insulated gear. So it can be installed exactly where needed—even subsurface—without compromising aesthetics. Your customers are happier and you save money through reduced trenching and shorter cable runs.

Safer to Operate

Ordinary elbow gear does isolate operating personnel from medium-voltage components—that is, until you need to operate it! Consider a routine operation such as isolating a downstream cable for repair. With conventional gear, two or more specially trained operators need to:

1. Remove the elbows from their bushings using shotgun clamp sticks . . . a tedious, awkward task.
2. Test the cables using an ungainly clamp-stick-mounted voltage tester.
3. Move the elbows to parking stands, along with grounding bushings or elbows . . . also an unwieldy task.
   
   But with Vista gear, just one person, using a simple operating handle, merely needs to:

• Rotate the switch operating shaft to the “open” position, then confirm the open gap through the large viewing window. Since the hinge end of the switch is connected to the bushings, the bushings—and hence the cables—are isolated from other medium-voltage components in the gear.
• Test for voltage simply using the push-button voltage indicator that’s capacitively coupled to the bushings.
• Rotate the switch operating shaft to the integral “grounded” position. Then confirm grounding through the viewing window.
  
  Vista gear is certified arc-resistant per IEC 298 Appendix AA for arcs occurring internal to the gear.

Complete System Coordination

Vista gear’s unique microprocessor-based overcurrent control features special, customizable “coordinating” speed time-current characteristic curves that provide complete coordination with upstream relays and downstream fuses. Conventional “E” and “K” speed curves are available too. See page 47.

Separate phase- and ground-overcurrent curves coordinate with source-side breakers having ground-trip settings. Both main and tap curves are provided, for complete coordination between fault interrupters applied on main feeders and those applied on subloop taps.

The overcurrent control is programmed with a PC, in the shop or in the field . . . no knobs or dials to compromise security. It features a handy event recorder that captures information on the last twelve operations of each fault interrupter.

Fault interrupters can also be tripped remotely by external relays.