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TMV,

IND

IA

JULY

200

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UNISAFE PANEL WITH VD4 CIRCUIT BREAKER

PRODUCT PRESENTATION

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Unisafe:Indoor Metal Clad Switchgear Cubicle

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UNISAFE PANEL

Designed and type tested to meet requirements of IEC60298 & 60694 / IS:3427

Air insulated indoor switchgear Metal clad construction Independent exhaust vents for

all HT compartments Internal arc tested IP4X degree of protection

externally - IP5X available as option

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UNISAFE PANEL

Integral Earthing Switch optional

Normal service conditions: Min ambient temp:-5oC Max ambient temp:+40oC

Quality System Certification- ISO 9001

Environmental Management System- ISO 14001

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BREAKER COMPARTMENT

Test position of circuit breaker behind closed door

Racking in/out of breaker from test to service position and vice-versa with cubicle door closed only

Mechanical interlock to prevent racking in/out of breaker, when breaker is in closed position

Live parts covered by automatic shutters when breaker is racked out

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METERING COMPARTMENT

Metering compartment with numerical /static /electro-magnetic relays, indicating meters, lamp and control switches

Protection and measuring apparatus customized as per requirement

Option of REF542 plus, composite unit for protection, measurement, control, signalling, interlock, automation and communication

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CABLE AND CT COMPARTMENT

Spacious construction to accommodate 1 set of CTs and 2 runs of cables

Option of rear extension to accommodate extra CTs or cables

Adequate height for cable termination

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PT COMPARTMENT

Withdrawable line PT provided in the breaker panel

Removable fuses mounted on the PT

Safety shutters between PT & Cable compartment close automatically on PT withdrawal

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BUSBAR COMPARTMENT

Spacious busbar compartment for adequate air clearances

Option for busbar insulation available

Option for shrouds on joints available

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Construction details of Switchgear Cubicle type UNISAFE

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Construction details of Switchgear Cubicle type UNISAFE

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VD4 BREAKER

The VD4 type circuit breaker is designed and tested to meet requirements of IEC 62271-100 / IS : 13118

Vacuum used as insulation and arc interruption medium

Operationally safe and reliable Capable of interrupting small

magnetizing and capacitive currents

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VD4 BREAKER

Features of operating mechanism O-C-O operation without

recharging Closing spring charged by

motor in less than 15secs Electrical anti-pumping Provision for manual charging Synchronisation and fast auto

reclosure duty

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Vacuum Interrupter

1) Stem / Terminal

2) Twist protection

3) Bellows

4) Interrupter lid

5) Shield

6) Ceramic insulator

7) Shield

8) Contacts

9) Terminal

10) Interrupter lid

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Interruption principle

VACUUM ARC Vacuum arc is initiated by the separation of current

carrying contacts and is maintained till the current zero Two types of vacuum arc - Diffuse & Contracted

DIFFUSE TYPE It occurs while interrupting the rated current Single melting points form on the entire surface

of the cathode producing metal vapours which

support the arc The diffuse vacuum arc is characterised by

expansion over the contact surface and by an

even distribution of thermal stress over the contacts

surfaces. Negligible contact erosion

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Interruption principle

CONTRACTED TYPE Higher the interruption current, the arc tends

to be transformed from the diffuse into the

contracted type due to the Hall effect The arc contracts at the anode and as the

current increases further it tends to become

sharply defined. In this area there is an increase

in temperature with consequent thermal stress

on the contact.

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Interruption principle

SPIRAL CONTACTS To prevent overheating and contact erosion, the arc is kept rotating The special geometry of the spiral contacts generates a radial magnetic field in all the areas of the arc column An electromagnetic force is self generated and acts tangentially causing rapid arc rotation around the contact axis. The arc is forced to rotate and to involve a wider surface than that of a fixed controlled arc Apart from minimising thermal stress, contact erosion also is reduced which makes high short circuit current interruption possible. Maximum dielectric strength is restored within micro- seconds as the rapid reduction of current charge and rapid condensation of the metal vapours happens simultaneously along with the current zero.

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UNISAFE CROSS SECTIONAL DWG

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VD4 BREAKER DIMENSIONAL DRAWING

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TECHNICAL DETAILSDescription Unit Rating

Voltage kV 12

Frequency Hz 50

Current A up to 2000

Short time withstand kA 26.3 current (for 3 secs)

Peak withstand current kAp 66

Insulation level kVrms/kVp 28/75, 95kVp as option

WidthxDepthxHeight

up to 1250A b/b current mm 600 x 1550 x 2500

above 1250A b/b current mm 750 x 1550 x 2500

Weight with breaker (approx.) kg 1000

Degree of Protection-Enclosure IP4X, IP5X on request

UNISAFE PANEL

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TECHNICAL DETAILS

Description Unit RatingType VD4 12.0613E 12.06.20E 12.12.25 12.16.25

Voltage kV 12

Current A 800 800 1250 1600

Breaking capacity kA 13.1 20 26.3 26.3

Short time withstand kA 13.1 20 26.3 26.3 current (for 3 secs)

Peak withstand current kAp 33 50 66 66

Insulation level kVrms/kVp 28/75

Operating sequence O-3min-CO-3min-CO/ O-0.3secs-CO-3min-CO

Weight (approx.) kg 110 110 110 120

VD4 CIRCUIT BREAKER