Features include:

• 5 kV and 15 kV voltage classes
  

• 600 A and 1,200 A continuous current

• Siemens overcurrent protection relay

• Indoor type 1 enclosure

• Single and duplex switch types

• Large 8” x 18” (203 mm x 457 mm) viewing window

• Hinged, grounded metal barrier in front of switch blades

• 11-gauge doors, covers, and barriers

• Silver-plated copper bust

• Provisions for key interlocking

• Mechanical door and switch interlock

• Upper and lower ventilation louvers

• Glass-polyester bus supports

• Non-corrosive nameplate

• Space heater with thermostat (optional)

• NEMA CC1 hole patterns for cable termination

• Current transformers (CTs) - one per phase.

Modular configurations:

• Surge arresters
  
• Instrument transformers  - current transformers (CTs) or voltage transformers (VTs)
• Control power transformer (CPT)
• Power meter.

Standard outdoor features:

• Long-life space heaters (half-voltage)
  

• Bottom cover plate

• Externally removable filters

• 6” (152 mm) formed steel base.

Optional:

• UL or C-UL Listing
  

• Indoor type 2 drip-proof enclosure

• Indoor type 12 dust-resistant enclosure

• Outdoor non-walk-in type 3R enclosure

• High-track resistance bus supports

• Auxiliary switches (2 NO-2 NC)

• Mimic bus

• Ground studs (ball stud) type

• Screens and filters (indoor)

• Tin-plated copper bus

• Second set of current transformers.

Construction

SIEBREAK-VCB metal-enclosed interrupter switchgear enclosure is of metal-enclosed construction as described in ANSI/IEEE standards. The equipment is tested and factory assembled into convenient shipping groups. It is ruggedly constructed of 11-gauge sheet steel including the doors. The assembly employs bolted construction. SIEBREAK-VCB's modular design is available in many different enclosure types and bus configurations. The switch mechanism is arranged in the upper portion of the enclosure while the fuses or fixed-mounted circuit breaker are located in the lower portion. Switch and fuses or fixed-mounted circuit breaker are arranged for ease of operation and inspection. A large viewing window is standard for observing the position of the switch blades when the door is closed. The front door and switch operating mechanism are interlocked to prohibit access to the switch compartment when the switch is closed and prohibit operating the switch operating mechanism when the door is open.

Standards

SIEBREAK-VCB metal-enclosed switchgear meets or exceeds the requirements of the following standards:

• ANSI/IEEE C37.20.3
• ANSI/IEEE C37.20.4

• ANSI/IEEE C37.04

• ANSI/IEEE C37.09

• ANSI C37.54.

• ANSI C37.57
• ANSI C37.58
• CSA 22.2 No. 31 (for Canada)
• CSA 22.2 No. 58 (for Canada)
• CSA 22.2 No 193 (for Canada).

SIEBREAK-VCB switchgear assemblies can optionally be listed with UL and, for use in Canada, have C-UL listing certifying compliance with Canadian standards and codes.

Single-source application: Single switch and circuit breaker (left in image)

Single vertical section equipped with one 600 A or 1,200 A load-interrupter switch and fixed-mounted vacuum circuit breaker rated up to 15 kV with cable incoming-line termination and load-cable termination. Cable direction for incoming and outgoing cable entry either top or bottom with an option for close-coupled line or load connection to dry or liquid-filled type transformer.

Dual-dource application: Duplex (right in image)

Two close-coupled vertical sections each equipped with one 600 A or 1,200 A load-interrupter interrupter switch and a common bus connection to a fixed-mounted vacuum circuit breaker rated up to 15 kV. Incoming and outgoing cable direction for either top or bottom cable entry with an option for close-coupled load connection to dry- or liquid-filled type transformer.

Arc-flash mitigation is at the forefront today

NFPA 70E Standard for Electrical Safety in the Workplace® has increased the emphasis for greater measures for reducing arc-flash hazards in the secondary bus protection in the substation. Siemens SIEBREAK-VCB with operation and maintenance arc-flash reduction system (OMARS) offers a practical approach to providing both primary and secondary bus protection to reduce the incident energy associated with an arcing fault on the line side of the low-voltage

main circuit breaker, or on the low-voltage main bus if there is no low-voltage main circuit breaker.

The right solution to arc-flash hazard

SIEBREAK-VCB with OMARS solves the arc-flash safety hazard situation present in many existing installed substations in operation today with the traditional fused load-interrupter switch.

The fused primary load-interrupter switch in the existing substations can be replaced with SIEBREAK-VCB with OMARS to reduce the arc-flash hazard.

Configuration

Current transformers or sensors and protective relays can be installed in the low-voltage switchgear or switchboard for

input into SIEBREAK-VCB circuit protection system. In this configuration, the bus protection will be provided on the both the primary and secondary bus to reduce the arc-flash incident energy on the secondary.

Three ways for reducing the arc-fault incident energy

SIEBREAK-VCB is available in three advanced ways for reducing the incident arc-fault energy on the secondary bus of substation:

• Relay maintenance mode setting
• Fiber optics arc-flash detection system
• Short-circuit relay protection on the secondary bus.

Double-ended substation arrangement features and options

SIEBREAK-VCB applied in a double-ended substation arrangement offers several optional features including:

• Short-circuit protection on the secondary side of each transformer (secondary bus in the low-voltage equipment)
• Increased reliability and protection with redundancy between the protective relays located in each SIEBREAK unit
• Power metering with voltage transformer installed in SIEBREAK or the secondary equipment
• Transformer differential relay (87T) protection for enhanced system and transformer protection
• Arc-flash detection fiber for increased the safety against arc flash can be installed throughout the low-voltage equipment.

SIEBREAK-VCB configuration in low-voltage or medium-voltage substations

Reduction of arc-flash incident energy

For the configurations where SIEBREAK-VCB is used as the transformer primary for the low-voltage substation that is

configured with the arc-flash reduction technology, the incident energy can be reduced to as low as 2.1 cal/cm² with an

interrupting time of 60 ms.

By contrast, for the scenario where the traditional fused load-interrupter switch is used as the transformer primary for the low-voltage substation, the incident energy can be as high 38.3 cal/cm² (or even higher) with an interrupting time of 900 ms.

SIEBREAK-VCB is available in four advanced configurations for reducing the incident arc-fault energy on the secondary bus of substation:

Type SBVCB vacuum circuit breaker ratings

• No. 07 - Current transformers - Use of 600 V CTs in metal-clad switchgear
• No. 15 - Expected life of electrical equipment
  
• No. 16 - Bus joint fundamentals
• No. 17 - Main bus continuous current rating
• No. 18 - Bus joint and primary disconnect plating
• No. 19 - Bus joint current density
• No. 26 - Ground bus ratings
  
• No. 30 - Altitude correction factors
  
• No. 31 - Solar radiation correction factors
• No. 33 - Clearance requirements in switchgear and control equipment
• No. 44 - Anatomy of a short circuit
• No. 56 - Switchgear outdoor enclosure type - Why isn’t it NEMA 3?
• No. 57 - Arc-flash hazard labels
  
• No. 59 - Control power sources for switchgear
• No. 60 - Use of cable for connections in medium-voltage switchgear
• No. 66 - Clearances
• No. 75 - Ferroresonance in ungrounded systems with voltage transformers connected line-to-ground
• No. 79 - Working space required around electrical equipment
  
• No. 81 - Arc-flash incident energy mitigation
• No. 82 - Continuous current capability in ambient temperatures other than 40 °C
• No. 84 - Space heater - sizing and application principles
  
• No. 85 - Temperature limitations for user’s power cables
• No. 86 - Use of unshielded cables for connections in medium-voltage switchgear and motor controllers
• No. 88 - Application of maintenance grounds in switchgear
• No. 90 - Temperature ratings for external cables
• No. 91 - Current transformer relaying accuracies - IEEE compared to IEC
• No. 96 - Phase sequence versus phase arrangement
• No. 100 - Third-party listing - UL, C-UL and CSA
  
• No. 102 - Tapered bus
• No. 110 - Corrosion prevention effects on electrical equipment life
• No. 115 - Third-party listing/labeling and recognition
  
• No. 118 - Bolted construction vs. welded construction
  
• No. 119 - Momentary ratings – peak or rms?
  
• No. 120 - High-potential testing – current doesn’t matter!
  
• No. 122 - Current transformer thermal-rating factor
  
• No. 126 - Testing of vacuum interrupters with dc test sets
• No. 127 - High-voltage fuses - expulsion (power) and current-limiting types
• No. 128 - Arc-fault mitigation in unit substations with type SIEBREAK-VCB primary switchgear
• No. 131 - Heat generation estimation for SIEBREAK™ metal-enclosed interrupter switchgear
• Entire TechTopics catalog