Switchgear: Underground distribution switchgear from S&C

Switchgear design: S&C now offers another choice in metal-enclosed gear, the economical Vista SD Underground Distribution Switchgear. It is the first practical solid-dielectric switchgear with a visible open gap and field-replaceable bushings.

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Power distribution: S&C now offers another choice in metal-enclosed gear. Economical new Vista SD Underground Distribution Switchgear is the first practical solid-dielectric switchgear with a visible open gap and field-replaceable bushings. It features:
• Visi-Gap™ Load-Interrupter Switches. These vacuum load-interrupter switches provide three-pole live switching of 600-amp main feeders. The switches comply with IEEE Standard 1247 and IEC Standard 62271-103.
• Visi-Gap™ Fault Interrupters. These microprocessor-controlled vacuum fault interrupters provide three-pole live switching and protection of 600-ampere main feeders and 200- or 600-ampere taps, laterals, and sub-loops. Fault interrupters comply with both IEEE Standard C37.60 and IEC Standard 62271-111.

The elbow-connected switches and fault interrupters are encapsulated in an environmentally friendly solid-dielectric insulating material.

Vista SD Switchgear can be furnished with up to six “ways” (load-interrupter switches and/or fault interrupters), in ratings through 29 kV and 16 kA symmetrical interrupting. By handling more loads per assembly, fewer Vista SD Switchgear assemblies are required. Each load-interrupter switch and fault interrupter includes a manually operated, two-position isolating disconnect to provide a visible open gap.
• Easy-to-follow mimic bus and indicators on the front of the switchgear convey the position of each switch and fault interrupter and its isolating disconnect — and whether a fault interrupter has tripped in response to a fault.
• Easy-to-operate manual operating mechanism. Operating mechanisms for fault interrupters are “trip-free” . . . the opening spring is charged when the closing spring is charged, and will open the fault interrupter — based on the TCC curve in the overcurrent control — if the fault interrupter is closed into a fault.
• Factory-installed and wired motor operators, to facilitate remote power operation of load-interrupter switches and fault interrupters; are optionally available. The operators can be decoupled to permit testing of the motor and controls.
• Completely submersible and suitable for application in subsurface vaults subject to flooding. It is also available for above-grade application, in pad-mounted style enclosures.
• Considerably smaller than traditional air-insulated gear. So it can be installed exactly where it’s needed without compromising aesthetics. Consumers are happier and you save money through reduced trenching and shorter cable runs.

Simple to Operate
With Vista SD Underground Distribution Switchgear, routine operation, such as isolating a downstream cable for repair, is easy. Just one person, using either the manual handle or a suitable user-furnished universal pole equipped with a standard fitting, merely needs to:
1. Place the load-interrupter switch or fault interrupter operating mechanism in the “open” position, then confirm the open gap of the isolating disconnect through the large viewing window.
2. Test for voltage using the optional potential indication feature.

Vista SD Switchgear is furnished with a ground connection pad on each load-interrupter switch and fault interrupter, for terminating cable concentric neutrals. A continuous ground bus for the entire switchgear assembly is optionally available.

Complete System Coordination
Vista SD Underground Distribution Switchgear is furnished with the same microprocessor-based overcurrent control used in S&C Vista® Underground Distribution Switchgear. This proven reliable device offers 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.

Separate phase- and ground-overcurrent curves coordinate with source-side circuit breakers having ground-trip settings. Both main and tap curves are included 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. There are no knobs or dials to compromise security. The control features an event recorder that captures information on the last twelve operations of each fault interrupter.

External trip provisions are optionally available, permitting the fault interrupters to be tripped remotely by external controls or relays.

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