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1. UNISAFE PANEL WITH VD4 CIRCUIT BREAKER PRODUCT PRESENTATION
3. 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
4. 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
5. 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
6. 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
7. 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
8. 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
9. BUSBAR COMPARTMENT Spacious busbar compartment for adequate air clearances
Option for busbar insulation available
Option for shrouds on joints available
10. Construction details of Switchgear Cubicle type UNISAFE
11. Construction details of Switchgear Cubicle type UNISAFE
12. 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
13. 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
14. Vacuum Interrupter
15. 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
16. 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.
17. 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.
20. UNISAFE PANEL
21. VD4 CIRCUIT BREAKER