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MV Air Insulated Switchgear, Model Unisafe MV Indoor Vacuum Circuit Breaker, Model VD4
ABB - a global leader in power and automation technologies

ABB (www.abb.com) is a global leader in power and automation technologies that enable utility and industry customers to improve performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries.

ABB’s Power Technologies Division serves electric, gas and water utilities, as well as industrial and commercial customers with a wide range of products, services and solutions for power transmission and distribution. ABB offers turnkey solutions for substations, utility automation, HVDC and FACTS (Flexible AC Transmission System).
ABB’s power technologies product portfolio includes outdoor and indoor circuit breakers, gas insulated switchgear, power transformers, instrument transformers, disconnectors, capacitor banks and reactive power compensators.

ABB’s medium voltage product offering encompasses a complete range of innovative products, systems and technologies for applications in the 1 to 50 kV class. This includes indoor air insulated and gas insulated panels with vacuum and SF6 gas circuit breakers, outdoor vacuum and SF6 gas circuit breakers, ring main units, auto-reclosers, fuses, switch disconnectors and prefabricated modular solutions for power distribution.

Salient Features : Unisafe Cubicle
� Metal clad construction - all compartments are segregated from each other with metal sheets
� IP4X degree of protection externally & IP5X available as an option
� Internal arc tested
� Independent exhaust vents for all HT compartments
� Internal earthing switch (optional)
� The normal service performances are guaranteed under the following conditions:

Min. Ambient Temp.: -50C

Max. Ambient Temp.: -400C

Max. Rel. Humidity: 95%
� Small width panel - 600mm up to 1250A busbar rating
� Insulation level of 95kVp available on request
� Option of REF 542+, composite unit for protection, measurement, control, signalling, interlock, automation and communication


The Unisafe panel and VD4 circuit breaker are certified as complying with the ABB IndustrialIT architecture. In this architecture the Unisafe panel and VD4 circuit breaker are part of the PowerIT suite. The products complying with the IndustrialIT architecture can be effectively integrated in a system with high added value and a true ‘Plug & Produce’ mode. This product has been tested and certified as IndustrialIT Enabled, Level 0 - Information. All product information is supplied in interactive electronic format, compatible with ABB Aspect ObjectTM technology. The IndustrialIT commitment from ABB ensures that every enterprise building block is equipped with the integral tools necessary to install, operate, and maintain efficiently throughout the product lifecycle.

Air insulated indoor switchgear cubicle type Unisafe

The Unisafe cubicle is designed and type tested to meet requirements of IEC 60694 / IS:3427.

Metering compartment
� Metering compartment with numerical / static / electromagnetic relays, indicating meters, lamps and control switches
� Protection and measuring apparatus customised as per requirement

Busbar compartment
Spacious busbar compartment for adequate air clearances
Option for busbar insulation available
Option for shroud on joints available



Breaker compartment
� Test position of circuit breaker


� Racking in/out of breaker from ‘test’ to ‘service’ position and vice-versa with cubicle door closed
� Mechanical interlock to prevent racking in/out of breaker, when breaker is in closed position
� Live parts covered by automatic metallic shutters when breaker is racked out

PT compartment

Withdrawable line PT provided in the breaker panel

Removable fuses mounted on the PT

Safety shutters between PT and cable compartment close automatically on PT withdrawal

Cable and CT compartment

Spacious compartment to accommodate 1 set of CTs and 2 runs of cable

Option of rear extension to accommodate extra CTs or cables

Adequate height for cable termination


Technical details
Description Unit Rating
Rated Voltage kV 12
Rated Frequency Hz 50
Rated Busbar Current A up to 2000
Short time withstand current (3 sec) kA 26.3
kAp 66
Insulation levels kVrms/kVp 28/75*
Width x Depth x Height
up to 1250A mm 600 x 1550 x 2500
above 1250A mm 750 x 1550 x 2500
Weight with circuit breaker (approx) Kg 1000
Degree of protection
Enclosure IP4X
Between the compartments IP2X
Indoor switchgear – vacuum circuit breaker type VD4
The VD4 type circuit breaker is designed and tested to meet requirements of IEC - 62271-100 / IS: 13118.
Salient Features
� Vacuum used as insulation and arc interruption medium
� Operationally safe and reliable in a wide range of ambient temperatures (-)50 to 400C
� Capable of interrupting small magnetising and capacitive currents
� Features of operating mechanism:
– O-C-O operation without recharging

Closing spring charged by motor in less than 15 seconds

Electrical anti-pumping

Provision for manual charging

Synchronisation and fast auto reclosure duty
Technical details
Description Unit Rating
Type VD4 12.06.13E 12.12.25 12.16.25 12.20.25
Rated Voltage kV 12
Insulation Levels kVrms/kVp 28/75
Normal Current (400C amb.) A 800 1250 1600 2000
Breaking Capacity kA 13.1 26.3 26.3 26.3
Making Capacity kAp 33 66 66 66
Short time withstand current kA(3sec) 13.1 26.3 26.3 26.3
Opening time ms 55 (max)
Arcing time ms 15 (max)
Total Break time ms 70 (max)
Making time ms 75 (max)
Operating Sequence 0 -3min - CO - 3min - CO/
0 - 0.3sec - CO - 3min - CO
Weight (approx.) Kg 110 110 120 250

Quality assurance

All of ABB’s manufacturing facilities in India are ISO 9001 certified which reflects ABB’s commitment to quality. ABB is equally committed to environmental sustainability. The Nashik facility is certified under ISO 14001.

For more details please contact us


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