Vista® and Vista® SD

Underground Distribution Switchgear for Utilities

Improves reliability and safety while reducing maintenance costs Vista & Vista SD Underground Distribution Switchgear

Introduction Space constraints. Additionally, utilities that serve sprawling urban areas may face challenges with the physical footprint As the grid becomes more complex, utilities are facing a vari- of their gear. Compact medium-voltage switchgear that can ety of challenges pressuring them to reassess their medium- fit in a tight underground vault is often required to alleviate voltage switchgear. In fact, some switchgear even poses risks the safety concerns public-facing equipment presents. If the that increase operations and maintenance (O&M) expenses switchgear does not have clearly visible breaks, utility crews while reducing reliability. As utilities reevaluate the switch- can find it challenging to confirm the switchgear’s operation gear on their system, they importantly should consider the status while working in a vault. Moreover, if the switchgear scope of the challenges they may face and the breadth of does not have front-facing cable terminations and operators, switchgear products available that can best meet the needs crews may have difficultly installing and navigating around of today’s grid. the switchgear in a vault to effectively deenergize the device. Risks and expenses of oil-insulted switchgear. Oil- Fortunately, S&C’s Vista and Vista SD Underground insulated switchgear is a common utility choice. However, Distribution Switchgear provide a suite of solutions to such switchgear comes with environmental and maintenance address the specific challenges each utility faces. S&C challenges. Utilities must routinely monitor oil switchgear designed these solutions to provide reliable protection, to maintain performance, especially during colder months. regardless of location or environmental conditions, including Additionally, lack of routine maintenance can lead to equip- in areas that experience flooding. Both switchgear offerings ment failure, causing an outage to all customers serviced by are also available in multiple above- or below-grade instal- the affected line. Leaks from oil-insulated switchgear have lation styles and include sustainable insulation technology also had negative environmental impacts, resulting in costly options. With their single-handle operation, visible gaps, and clean-up efforts. Some oil-insulated switchgear also requires flexible cable orientations, Vista or Vista SD switchgear are mandatory testing, meaning more time, effort, and money simple to routinely operate. Vista and Vista SD switchgear can are wasted to routinely inspect the gear. tackle whatever challenges a utility might face. Regulatory pressures. Utilities are also facing greater pressure to limit the use of sulfur hexafluoride (SF6) gas and reduce the carbon footprints of their switchgear, with an increased focus on meeting corporate sustainability goals and adhering to forthcoming federal greenhouse gas regula- tions. As a result, utilities are reconsidering SF6 gas-insulated switchgear because of concerns operations may result in greenhouse gas emissions. Solid-dielectric switchgear can replace SF6 gas-insulated switchgear, but solid-dielectric technology has limitations, such as lower ratings and lack of three-position switching. In addition, solid-dielectric switchgear has a higher carbon footprint because of the type and mass of materials used in their construction and limited recyclability versus alternatives such as air- or gas-insulated switchgear.

2 Application

Vista Underground Distribution UnderCover™ Style. Out of sight, yet easy to operate from ground level, submersible UnderCover Style Vista switchgear Switchgear is ideal where aesthetics are important or where space limitations make it difficult to deploy gear above ground. Vista Underground Distribution Switchgear is designed to simplify operating tasks and enhance safety while Vault-Mounted Style. This style provides a compact minimizing the traditional switchgear footprint. Vista switching-and-protection solution for manholes, electrical switchgear introduces a new level of safety and simplicity by rooms, and sidewalk vaults, where space is very limited. A eliminating the need for cable-handling during routine single unit accommodates up to six load-interrupter switches, operations. Just one person is needed to operate Vista fault interrupters, or a combination of each. switchgear, and there’s no necessary exposure to medium Single-Way Wind-Turbine Style. This slim, single-way three- voltage. phase version fits through a 24-inch (610-mm) wide opening. Vista switchgear is available in manual, remote-supervisory, It provides connection and switching points for the medium- and source-transfer models in ratings through 38 kV and voltage cables from the generator output. Because of its side- 25 kA symmetrical short-circuit. All models are elbow- operation, it can be positioned alongside a wall. connected and enclosed in a submersible, welded steel tank. Mobile Heavy-Duty Style. This unique version of Vista Vista switchgear can accommodate any combination of up to switchgear is suitable for temporary or permanent six bus taps, load-interrupter switches, or fault interrupters. installations. Developed for the U.S. military, this small, Each model features load-interrupter switches and lightweight Vista switchgear style is specially designed to resettable vacuum fault interrupters or arc spinners in withstand the rigors of extended air transport at high altitude. series with disconnect switches. The load-interrupter switches provide three-pole live switching of 600-ampere or Vista Switchgear for Special Applications. Vista switchgear 900-ampere three-phase circuits. can be engineered to suit a variety of “special” applications. For example, if a utility expands a conventional metal- Vista switchgear is available using one of two different gas- enclosed switchgear lineup to accommodate two additional insulation technologies: SF gas or a new CO gas mixture 6 2 feeders—but there was only room for one more bay—a new option. The CO gas mixture has a 97 percent reduced CO e, 2 2 bay externally matching the others can be constructed that or carbon dioxide equivalent. Vista switchgear is available in contains a Vista switchgear unit. six installation styles: Pad-Mounted Style. This style 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.

3 Application

Vista SD Underground Distribution S&C Visi-Gap® Fault Interrupters use a vacuum interrupter in series with a manually operated two-position isolating Switchgear disconnect for three-pole load switching of 200- or S&C Vista SD Underground Distribution Switchgear features 600-ampere circuits and fault interrupting through 16 kA load-interrupter switches for switching 600-ampere main symmetrical at 17.5 kV and through 12.5 kA symmetrical at feeders and microprocessor-controlled fault interrupters for 29 kV. the switching and protection of 600-ampere main feeders Vista SD switchgear is offered in four installation styles: and 200- or 600-ampere taps, laterals, and subloops. These Pad-Mounted Style. Furnished with an optionally available elbow-connected components are encapsulated in an pad-mounted style enclosure for above-grade installations; environmentally friendly solid-dielectric insulating material. available in mild steel or stainless steel Vista SD switchgear is available in ratings through 29 kV and 16 kA symmetrical interrupting. Multi-Way Vault-Mounted Style. Usable in submersible vaults with multiple source ways and/or multiple protected Because Vista SD switchgear is compact, it can be installed ways (taps) exactly where it’s needed. It’s completely submersible and thus suitable for installation in subsurface vaults subject Single-Way Vault-Mounted Style. Ideally suited for use on to flooding. Single-way Vista SD switchgear assemblies are the primary side of network transformers ideally suited for application on the primary side of network PMH and PME Styles. Matches the footprint and phase con- transformers. Multi-way assemblies, from three to six load- figuration of PMH and PME Pad-Mounted Gear interrupter switches or fault interrupters, are also available. S&C Visi-Gap® Load-Interrupter Switches use a vacuum interrupter in series with a manually operated two-position isolating disconnect for three-pole live switching of 600-ampere three-phase circuits.

4 Construction

Vista Underground Distribution Switchgear

A B H

C D E F

Optional VOLTAGE Indicator with Liquid-Crystal Microprocessor-Based Overcurrent Control — A Display —Includes a self-test feature GF Housed in a watertight enclosure (Current transformers provide power and signal inputs.) Compact Welded-Steel Tank —Protects switching B and protection components from the environment Blade-Viewing Window —Located under (Stainless steel construction is standard in G this cover, allows visual confirmation of the blade UnderCover Style.) position

Pressure Gauge—Located under window, Motor Operators—The operators facilitate remote C temperature and altitude compensated H power operation of load-interrupter switches and fault interrupters. The operators can be decoupled Operating Mechanisms —For switches and fault to permit testing of the motor and controls. Factory- D interrupters, padlockable in any position installation is optionally available.

Operation Selector—Prevents operations from EF the Closed position directly to Grounded position and vice versa

5 Construction

Vista SD Underground Distribution Switchgear

C E

A B

Visi-Gap Load-Interrupter Switches —Vacuum Easy-to-Operate Manual Operating A load-interrupter switches that provide three-pole D Mechanism—Allows for “trip-free” operation of live switching of 600-ampere main feeders fault interrupters (The opening spring is charged when the closing spring is charged and will open Visi-Gap Fault Interrupters —Microprocessor- the fault interrupter—based on the time-current B controlled vacuum fault interrupters that provide characteristic (TCC) curve in the overcurrent three-pole live switching and protection of control—if the fault interrupter is closed into a fault.) 600-ampere main feeders and 200-or 600-ampere taps, laterals, and sub-loops Motor Operators—The operators facilitate remote EF power operation of load-interrupter switches and Mimic Bus and Indicators —Convey the position fault interrupters. The operators can be decoupled C of each switch and fault interrupter and its isolating to permit testing of the motor and controls. Factory- disconnect—and whether a fault interrupter has installation is optionally available. tripped in response to a fault

6 Features

Simple, One-Handed Operation. Access and operate the initiates operation of the resettable fault interrupters. This switchgear without cable-handling● or high-voltage expo- proven device offers special, customizable “coordinating” sure for a higher level of safety. speed TCC curves that provide complete coordination with upstream relays and downstream fuses. Separate phase- and No External Grounds. Ground medium-voltage cables using ground-overcurrent curves coordinate with source-side cir- a standard internal ground switch. External grounds are not cuit breakers having ground-trip settings. Both main and tap required.● curves are included for complete coordination between fault Dust, Corrosion, and Leak-Proof. Prevent leaking, rusting, interrupters applied on main feeders and those applied on or contamination to switchgear with a hermetically sealed subloop taps. tank. The overcurrent control is programmed with a personal Submersible. Switchgear is built to operate without being computer, in the shop or in the field. The overcurrent control affected by water hazards, such as storm-surge flooding or records up to a total of 64 of the most recent trip events. tides. Zero Emissions■. Solid-dielectric and vacuum interrupters High degree of protection against the environment. The use materials with zero global-warming potential. hermetically sealed tank protects elements from exposure to Aesthetic Improvement●. The switchgear comes in a com- moisture or wildlife. pact, low-profile design. At 15, 25, and even 34.5 kV, pad- Large viewing windows and visible open gap. This pro- mounted Vista switchgear is 6 to 14 inches (152 to 356 mm) vides a clear indication of the switch position and a clear view shorter than, and its total real-estate requirement is less than of the isolating disconnects, allowing operating personnel to one-third of, the average gas-insulated gear and less than easily confirm the positions of load-interrupter switches and half the real estate of metal-clad switchgear. See the figure fault interrupters. below. Improved Worker Safety. No fuse handling is required, Another innovative installation offering is the UnderCover minimizing access and exposure to medium-voltage Style, which is ideal for areas with stringent real-estate components. restrictions or where aesthetics are important. The Vista Overcurrent Control. Superior coordination, flexibility, and switchgear is installed underground, but all operations are reliability are made possible with a self-powered and user- easily performed by one operator aboveground. friendly control. The overcurrent control detects faults and ● Applies to Vista Underground Distribution Switchgear only. ■ Applies to Vista SD Underground Distribution Switchgear only.

252 inches (6400.8 mm)

Typical 38-kV Metal-Clad Outdoor Switchgear (6 Ways)

113 inches (2870.2 mm) 115.67 inches (2938.02 mm)

Vista Underground Distribution Switchgear 38 kV (6 Ways) 39.31 inches (998.47 mm)

Vista Underground Distribution Switchgear versus typical metal-clad outdoor switchgear size comparison.

7 Options

Vista Underground Distribution phase condition. An optional Overcurrent Lockout feature prevents an automatic transfer operation that would close a Switchgear source load-interrupter switch into a fault. An optional com- munications card lets users rapidly upload event log to their Manual. Manual Vista Underground Distribution Switchgear desktop computer. is engineered to simplify operations, and it provides an intui- tive solution to managing complex medium-voltage power- Portable Motor Operator. Local motor operation of Vista delivery needs. All manual Vista switchgear units are oper- switchgear is also available for users who do not require a ated using a specially designed operating handle. It has been complete automation package. The operator easily attaches designed to prevent switch operators from going directly to to any load-interrupter switch or single-pole or three-pole the Ground position from the Closed position and vice versa. fault interrupter. The hand-held control features OPEN, CLOSE, and GROUND pushbuttons, an ENABLE button to Remote Supervisory. Available in ratings through 38 kV, prevent inadvertent operation, and a READY indicating light. Remote Supervisory Vista Underground Distribution Switchgear provides automated switching and fault protec- External Trip. External trip provisions are optionally avail- tion and—when applied in the High-Speed Fault-Clearing able, permitting the fault interrupters to be tripped remotely System—can also perform auto-sectionalizing without trip- by external controls or relays. ping the main breaker. It incorporates the same outstanding Remote Low-Pressure Alarm. In addition to the gas pres- features as manual Vista switchgear and can be specified sure indication on the gear, users can specify a remote low- with a communication and control equipment group for a pressure alarm. This will allow a SCADA or monitoring system completely integrated, self-powered switching and protec- to engage. S&C can also develop a monitoring solution via its tion package. Users may choose a terminal unit, including a Global Support and Monitoring Center. 6800 Series Automatic Switch Control. These sophisticated controls support S&C’s self-healing, scalable IntelliTeam® SG Auxiliary Contacts. Auxiliary contacts provide an indication Automatic Restoration System— a universal smart grid solu- of switch and interrupter status. They can be ordered and tion offering unmatched interoperability. Users also have a used immediately in a monitoring or remote-supervisory choice of communication device, including a SpeedNet™ application or to provide future opportunities to do so. Radio. 15.5-kV Loadbreak Switches Rated 40 kA Symmetrical Source-Transfer. Available in ratings through 38 kV, Source- Short Time. Vista Underground Distribution Switchgear Transfer Vista Underground Distribution Switchgear provides models with 15-kV loadbreak switches rated 40 kA symmetri- fully automatic primary-selective service and fault protec- cal short time are an ideal fit for sectionalizing underground tion for one, two, or three critical load circuits. It’s available distribution networks. Switchgear in urban areas is frequently in common-bus and split-bus configurations. This smart installed subsurface or in street or sidewalk vaults, so a com- grid solution incorporates the same outstanding features as pact size is generally required along with an ability to with- manual Vista switchgear, plus the Micro-AT® Source-Transfer stand routine flooding. Available fault-current levels also may Control, motor operators, three-phase voltage sensing on be very high and exceed the capabilities of most compact source ways, and voltage transformers for control power. and submersible switchgear. Unlike lower-rated switchgear, it eliminates the need to incorporate current-limiting devices, The Micro-AT Source-Transfer Control offers self-healing which are difficult to coordinate and increase operating response to distribution system problems. It transfers on complexity. loss of source, voltage unbalance, or any source-side open-

8 Options

Vista SD Underground Distribution Switchgear Motor Operators. Factory-installed motor operators are optionally available to facilitate remote power operation of load-interrupter switches and fault interrupters. They can be decoupled from the operating mechanisms to permit testing without changing the positions of the switches or fault interrupters. The motor operators require a user- furnished 100-240 Vac 50/60-Hz control power source. Cable Center-Line Adapters. Adapters facilitate replacement of traditional air insulated pad-mounted gear without having to change cable terminations.

9 Ratings

Vista Underground Distribution Switchgear

Table 1. 50/60-Hz ANSI Ratings—IEC Ratings in Parentheses①

kV Amperes, RMS Fault Interrupter Load-Interrupter Switch 10-Time Duty-Cycle Main Bus Short- Cont., Load 10-Time Cont., Load 10-Time System Fault-Closing, Sym. Mom. and Max BIL Cont. Circuit, Dropping, Duty-Cycle Dropping, Duty-Cycle Class Into Into One-Second, Current Sym. and Load Fault- and Load Fault-Closing, Closed Grounded Sym. Splitting② Interr., Sym. Splitting② Sym.③ Position Position 600 12 500 200 12 500 12 500 12 500 600 12 500 12 500 15.5 15.5 95 (630) (12 500) (200)■ (12 500) (12 500) (12 500) (630)▼ (12 500) (12 500) (12) (15.5) (95) 600 25 000 600 25 000 25 000 600 25 000 ◆ ◆ (630)● (25 000) (630)▲ (25 000) (25 000) (630)□ (25 000) 12 500 200 12 500 12 500 12 500 600 16 000 12 500 27 29 125 600 (12 500) (200)■ (12 500) (12 500) (12 500) (630)▼ (16 000) (12 500) (24) (29) (125) (630)● 25 000 600 25 000 25 000 600 25 000 ◆ ◆ (25 000) (630)▲ (25 000) (25 000) (630)□ (25 000) 12 500 200 12 500 12 500 12 500 600 16 000 12 500 38 38 150 600 (12 500) (200)■ (12 500) (12 500) (12 500) (630)▼ (16 000) (12 500) (36) (38) (150) (630)● 25 000 600 25 000 25 000 600 25 000 ◆ ◆ (25 000) (630)▲ (25 000) (25 000) (630)□ (25 000)

① Refer to the nearest S&C Sales Office for other possible ratings. ▲ 900 (900) amperes when switchgear is furnished with optional ② Parallel or loop switching. Fault interrupters and load-interrupter 900-ampere fault interrupters plus an optional copper bus. switches can switch the magnetizing current of transformers associ- ◆ 25 000 (25 000) amperes symmetrical three-time duty-cycle fault- ated with the load-dropping rating. Unloaded cable switching rating: closing rating; 16 000 (16 000) amperes symmetrical 10-time duty-cycle 10 amperes at 15.5 kV; 20 amperes at 29 kV and 38 kV. fault-closing rating. ③ Applicable to fault closing into closed or grounded position. ▼ 200 (200) amperes when switchgear is furnished with optional ● 1200 (1200) amperes when switchgear is furnished with optional 200-ampere bushing wells at load-interrupter switch terminals. copper bus. □ 900 (900) amperes when switchgear is furnished with optional ■ 600 (630) amperes when switchgear is furnished with optional 900-ampere load-interrupter switches plus an optional copper bus. 600-ampere bushings at fault interrupter terminals.

10 Ratings

Vista SD Underground Distribution Switchgear Table 2. Pad Mount and Vault Configurations 50/60-Hz IEEE Ratings—(IEC ratings in parenthesis)

Voltage, kV Amperes, RMS

Main Bus Visi-Gap® Fault Interrupter Visi-Gap® Load-Interrupter Switch

Continuous, Continuous, Three-Time, System Momentary Max BIL Short- Load Dropping, Short-Circuit Load Duty-Cycle, Class Continuous and Three- Circuit, RMS, and Load Interrupting Dropping, and Fault Closing, Current Second, Symmetrical Splitting Load Splitting Symmetrical Symmetrical ①② ① ③

15 (12) 17.5 (12) 95 (75) 600 (630) 16 000● 600 (630) 16 000● 600 (630) 16 000 16 000 27 (24) 29 (24) 125 (125) 600 (630) 12 500 600 (630) 12 500 600 (630) 12 500 12 500

① Parallel or loop switching. Load-interrupter switches and fault interrupt- ② 200 amperes if fault interrupters are furnished with optional 200-ampere ers can switch the magnetizing current of transformers associated with this bushings. rating. Unloaded cable-switching capability: 10 amperes at 17.5 kV; ③ Applicable to fault closing into Closed position. 20 amperes at 29 kV. Load-interrupter switches and fault interrupters can also switch single capacitor banks through 1800 kvar. ● 12,500 amperes if fault interrupters are furnished with optional 200-ampere bushings.