3 UNISAFE PANELDesigned and type tested to meet requirements of IEC60298 & / IS:3427Air insulated indoor switchgearMetal clad constructionIndependent exhaust vents for all HT compartmentsInternal arc testedIP4X 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:+40oCQuality System Certification- ISO 9001Environmental Management System- ISO 14001
5 BREAKER COMPARTMENTTest position of circuit breaker behind closed doorRacking in/out of breaker from test to service position and vice-versa with cubicle door closed onlyMechanical interlock to prevent racking in/out of breaker, when breaker is in closed positionLive parts covered by automatic shutters when breaker is racked out
6 METERING COMPARTMENTMetering compartment with numerical /static /electro-magnetic relays, indicating meters, lamp and control switchesProtection and measuring apparatus customized as per requirementOption 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 cablesOption of rear extension to accommodate extra CTs or cablesAdequate height for cable termination
8 PT COMPARTMENT Withdrawable line PT provided in the breaker panel Removable fuses mounted on the PTSafety shutters between PT & Cable compartment close automatically on PT withdrawal
9 BUSBAR COMPARTMENTSpacious busbar compartment for adequate air clearancesOption for busbar insulation availableOption for shrouds on joints available
10 Construction details of Switchgear Cubicle type UNISAFE
11 Construction details of Switchgear Cubicle type UNISAFE
12 VD4 BREAKERThe VD4 type circuit breaker is designed and tested to meet requirements of IEC / IS : 13118Vacuum used as insulation and arc interruption mediumOperationally safe and reliableCapable of interrupting small magnetizing and capacitive currents
13 VD4 BREAKER Features of operating mechanism O-C-O operation without rechargingClosing spring charged by motor in less than 15secsElectrical anti-pumpingProvision for manual chargingSynchronisation and fast auto reclosure duty
15 Interruption principle VACUUM ARCVacuum arc is initiated by the separation of currentcarrying contacts and is maintained till the current zeroTwo types of vacuum arc - Diffuse & ContractedDIFFUSE TYPEIt occurs while interrupting the rated currentSingle melting points form on the entire surfaceof the cathode producing metal vapours whichsupport the arcThe diffuse vacuum arc is characterised byexpansion over the contact surface and by aneven distribution of thermal stress over the contactssurfaces.Negligible contact erosion
16 Interruption principle CONTRACTED TYPEHigher the interruption current, the arc tendsto be transformed from the diffuse into thecontracted type due to the Hall effectThe arc contracts at the anode and as thecurrent increases further it tends to becomesharply defined. In this area there is an increasein temperature with consequent thermal stresson the contact.
17 Interruption principle SPIRAL CONTACTSTo prevent overheating and contacterosion, the arc is kept rotatingThe special geometry of the spiral contactsgenerates a radial magnetic field in all the areasof the arc columnAn electromagnetic force is self generated andacts tangentially causing rapid arc rotation aroundthe contact axis. The arc is forced to rotate and toinvolve a wider surface than that of a fixed controlled arcApart from minimising thermal stress, contact erosionalso is reduced which makes high short circuit currentinterruption possible.Maximum dielectric strength is restored within micro-seconds as the rapid reduction of current charge andrapid condensation of the metal vapours happenssimultaneously along with the current zero.
20 UNISAFE PANEL TECHNICAL DETAILS Description Unit Rating Voltage kV 12 Frequency Hz 50Current A up to 2000Short time withstand kA current (for 3 secs)Peak withstand current kAp 66Insulation level kVrms/kVp 28/75, 95kVp as optionWidthxDepthxHeightup to 1250A b/b current mm 600 x 1550 x 2500above 1250A b/b current mm 750 x 1550 x 2500Weight with breaker (approx.) kgDegree of Protection-Enclosure IP4X, IP5X on request
21 VD4 CIRCUIT BREAKER TECHNICAL DETAILS Description Unit Rating Type VD E EVoltage kV 12Current ABreaking capacity kAShort time withstand kA current (for 3 secs)Peak withstand current kApInsulation level kVrms/kVp 28/75Operating sequence O-3min-CO-3min-CO/ O-0.3secs-CO-3min-COWeight (approx.) kg