Vista® SD Underground Distribution Switchgear
For outdoor distribution, 17.5 kV and 29 kV
Introducing the industry’s first practical solid-dielectric switchgear with a visible open gap and field-replaceable bushings
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.
Features
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:
- 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.
- 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.
Installation Styles
Pad-Mounted Style Vista SD Underground Distribution Switchgear
Vista SD can be furnished with an optionally available pad-mounted style enclosure for above-grade installations. Pad-mounted enclosure meets IEEE C57.12.28 and C57.12.29. Available in mild steel or stainless steel.
Multi-Way Vault-Mounted Style Vista SD Underground Distribution Switchgear
Multi-way Vista SD switchgear can be used in submersible vaults with multiple source ways and/or multiple protected ways (taps).
Single-Way Vault-Mounted Style Vista SD Underground Distribution Switchgear
Single-way Vista SD switchgear is ideally suited for use on the primary side of network transformers. Model 101 (fault interrupter) shown.
Ratings & Current Configurations
| kV | Amperes, RMS | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| System Class | Max | BIL | Main Bus Continuous Current | Short-Circuit, RMS,Sym. | Fault Interrupter | Load-Interrupter Switch | |||
| Continuous, Load Dropping, and Load Splitting | Short-Circuit Interrupting | Continuous, Load Dropping, and Load Splitting | Momentary and One-Second, Sym. | Three-Time Duty-Cycle, Fault Closing, Sym. | |||||
| 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) |
16 000 | 16 000 |
Parallel or loop switching. Load-interrupter switches and fault interrupters can switch the magnetizing current of transformers associated with this rating. Unloaded cable switching capability: 10 amperes at 17.5 kV, 20 amperes at 29 kV. Load-interrupter switches and fault interrupters can also switch single capacitor banks through 1800 kVAR.
200 amperes if fault interrupters are furnished with optional 200-ampere bushing wells.
Applicable to fault closing into closed position.
12 500 amperes if fault interrupters are furnished with optional 200-ampere bushing wells.
Circuit Configurations
Model number indicates the total number of ways, as well as the number of load-interrupter switch ways and fault-interrupter ways. For example, Model 431 has “4” ways—“3” load-interrupter switch ways and “1” fault-interrupter way.
Overcurrent Control
Vista SD Underground Distribution Switchgear furnished with fault-interrupter ways includes a unique microprocessor-based overcurrent control that detects faults and initiates operation of the resettable fault interrupters. The control is readily programmed in the shop or the field using your personal computer. It offers exceptional flexibility and reliability, and includes features unavailable in other manufacturers’ devices—or only available at substantial extra cost.
- Four families of curves. Standard “E” and “K” speed curves plus special, customizable “coordinating-speed” tap and main curves.
- Superior coordination with upstream protective devices and downstream power fuses. Minimum total clearing time, from initiation of a fault to total clearing, is 40 milliseconds (2.5 cycles). Coordinating-speed curves provide optimal coordination on underground distribution systems.
- Custom curve attributes. Coordinating-speed curves can be easily modified to include instantaneous pickup levels and definite time delays.
- Separate phase and ground curves are standard — allowing better coordination with source-side breaker trip settings.
- No extra “wake-up” time. If a fault-interrupter way is closed into a fault, the fault interrupter will trip and clear the fault per the selected TCC, with no additional delay.
- Self-powered. Current transformers on fault-interrupter ways provide sensing and power.
- Event recorder captures information on the last twelve operations of each fault interrupter.
- Optional external trip provisions offer additional functionality. Input from external sources such as transformer sudden-pressure relays can also trip the fault interrupters.
Terminal Emulator Programs for Vista® UDS Overcurrent Control
A terminal emulator program such as “HyperTerminal” is required to program the Vista Overcurrent Control and download event log data from it. Newer versions of the Microsoft® Windows® operating system no longer include HyperTerminal. If you are using such a newer version, you’ll need to obtain an appropriate terminal emulator program and install it on your personal computer.
Schweitzer Engineering Laboratories AcSELerator QuickSet
This emulator program can be used to program the Vista Overcurrent Control and download event log data from it. It cannot be used to install firmware upgrades. A download of AcSELerator QuickSet is available at no charge from SEL’s website.
If you do not have administrative rights, you’ll need to contact your IT department to install the software on your computer.
Hilgraeve HyperTerminal Private Edition
This emulator program can be used to program the Vista Overcurrent Control, download event log data from it, and install firmware upgrades. A download of HyperTerminal Private Edition can be purchased from Hilgraeve’s website.
If you do not have administrative rights, you’ll need to contact your IT department to install the software on your computer.
Additional Information
Please refer to S&C Instruction Sheet 695-515, “Instructions for Programming S&C Overcurrent Control,” and S&C Instruction Sheet 695-515A, “Instructions for Connecting Personal Computer to S&C Overcurrent Control” for additional details.
Coordinaide™ — The S&C Protection and Coordination Assistant
Coordinaide™ lets you quickly and easily select the optimal protective device (e.g., fuses, TripSaver® II Cutout-Mounted Reclosers, Vista® Underground Distribution Switchgear, or IntelliRupter® PulseCloser® Fault Interrupters) to:
- Protect transformers against damaging overcurrents and coordinate with primary- and secondary-side protective devices. See how S&C's novel Transformer Protection Index (TPI) can be used to determine if the primary fuse will protect against certain types of secondary-side faults, including arcing phase-to-ground secondary-side faults.
- Protect capacitor units against case rupture.
- Protect underground cables from insulation damage due to excessive temperatures.
- Protect overhead conductors from damage due to annealing.
- Confirm the proper operation of protective devices against incident-arc energy curves for various Personal Protective Equipment (PPE) levels.
- Selectively coordinate two or more devices in series to minimize service interruptions.
Coordinaide Help
