Medium Voltage Products VD4 Medium voltage vacuum …

1 VD4 Medium Voltage vacuum circuit-breaker12 kV - A - 63 kA36 kV - A - kAMedium Voltage Products312345515384147 DESCRIPTIONCIRCUIT-BREAKER SELECTION AND ORDERINGSPECIFIC PRODUCT CHARACTERISTICSOVERALL DIMENSIONSELECTRICAL CIRCUIT DIAGRAM451 General6 Quenching principle of ABB interrupters8 Versions available8 Fields of application8 Standards and approvals8 Service safety9 Accessories12 Operating mechanism12 Technical documentation14 Quality System14 Test laboratory14 Environmental Management System14 Health and Safety Management System14 DESCRIPTION6 DESCRIPTIONG eneralThe VD4 are a synthesis of the renownedtechnology in designing and constructing vacuuminterrupters embedded in resin poles, and ofexcellency in design, engineering and productionof Medium Voltage the interrupter in resin makes thecircuit-breaker poles particularly sturdy andprotects the interrupter against shocks, accumula-tion of dust and vacuum interrupter houses the contacts andmakes up the interrupting interruption in vacuumThe vacuum circuit-breaker does not require aninterrupting and insulating Medium .

2 In fact, theinterrupters do not contain ionisable any case, on separation of the contacts anelectric arc is generated made up exclusively ofmelted and vaporised contact electric arc remains supported by the externalenergy until the current is cancelled in the vicinityof natural zero. At that instant, the rapid reductionin the load density carried and the rapid conden-sation of the metallic vapour, leads to extremelyrapid recovery of the dielectric vacuum interrupter therefore recovers theinsulating capacity and the capacity to withstandthe transient recovery Voltage , definitively extin-guishing the high dielectric strength can be reached inthe vacuum , even with minimum distances.

3 Interruption of the circuit is also guaranteed whenseparation of the contacts takes place a fewmilliseconds before passage of the currentthrough natural interruption techniqueVacuum contacts protected against oxidationand contaminationVacuum interrupter embedded in the resinpolesInterrupter protected against shocks, dustand humidityOperation under different climatic conditionsLimited switching energyStored energy operating mechanism withanti-pumping device supplied as standardSimple customisation with a complete rangeof accessoriesFixed and withdrawable versionCompact dimensionsSealed-for-life polesSturdiness and reliabilityLimited maintenanceCircuit-breaker racking in and racking outwith door closedIncorrect and hazardous operations areprevented thanks to special locks in theoperating mechanism and in the truckHigh environmental compatibilityVacuum interrupter embedded in resin pole1

4 Upper terminal2 vacuum interrupter3 Resin housing4 Stem of movingcontact5 Lower terminal6 Flexible connection7 Tie-rod spring fork8 Tie-rod9 Pole fixing10 Connection tooperatingmechanism1 The structureThe operating mechanism and the poles are fixedto a metal frame which is also the support for thefixed version of the circuit-breaker. The compactstructure ensures sturdiness and from the isolating contacts and the cord withplug for connection of the auxiliary circuits, thewithdrawable version is completed with the truckfor racking it into and out of the switchgear orenclosure with the door special geometry of the contacts and thematerial used, as well as the limited duration andlow Voltage of the arc, guarantee minimum contactwear and long life.

5 Furthermore, the vacuumprevents their oxidation and mechanismThe low speed of the contacts, together with thereduced run and low mass, limit the energyrequired for the operation and therefore guaranteeextremely limited wear of the system. The circuit-breaker therefore only requires VD4 circuit-breakers use a mechanicaloperating mechanism, with stored energy and freetrip. These characteristics allow opening andclosing operations independent of the principle of ABB interrupters12345789106In a vacuum interrupter, the electric arc starts at the moment of contact separation and ismaintained until zero current and can be influenced by magnetic arc diffuse or contractedFollowing contact separation, single melting points form over the entire surface of the cathode.

6 Producing metal vapours which support the diffuse vacuum arc is characterised by expansion over the contact surface and by an evendistribution of thermal stress on the contact the rated current of the vacuum interrupter, the electric arc is always of the diffuse erosion is very limited and the number of current interruptions very the interrupted current value increases (above the rated value), the electric arc tends to betransformed from the diffuse into the contracted type, due to the Hall at the anode, the arc contracts and as the current rises further it tends to becomesharply defined.

7 Near the area involved there is an increase in temperature with consequentthermal stress on the prevent overheating and erosion of the contacts, the arc is kept rotating. With arc rotation itbecomes similar to a moving conductor which the current passes throughThe spiral geometry of ABB vacuum interrupter contactsThe special geometry of the spiral contacts generates a radial magnetic field in all areas ofthe arc column, concentrated over the contact electromagnetic force is self-generated and this acts tangentially, causing rapid arcrotation around the contact means the arc is forced to rotate and to involve a wider surface than that of a fixedcontracted from minimising thermal stress on the contacts.

8 All this makes contact erosionnegligible and, above all, allows the interruption process to be controlled even with very vacuum interrupters are zero-current interrupters and are free of any reduction in the current charge and rapid condensation of the metal vapourssimultaneously with the zero current, allows maximum dielectric strength to be restoredbetween the interrupter contacts within protection3 Bellows4 Interrupter housing5 Shield6 Ceramic insulator7 Shield8 Contacts9 Terminal10 Interrupter housingVacuum interrupterStandards and approvalsThe VD4 circuit-breakers comply with the IEC 62271-100, VDE 0671 part 100, CEI 17-1 file 1375 Standards and with those of the major VD4 circuit-breakers have undergone the testsindicated below and guarantee the safety andreliability of the apparatus in service in anyinstallation.

9 Type tests: temperature rise, withstand insulationat power frequency, withstand insulation at lightningimpulse, short-time and peak withstand current,mechanical life, short-circuit current making andbreaking capacity, and no-load cable availableThe VD4 circuit-breakers are available in the fixedand withdrawable version with front withdrawable version is available for UniGearZS1 and type switchgear,PowerCube and Powerbloc of applicationThe VD4 circuit-breakers are used in powerdistribution for control and protection of cables,overhead lines, transformer and distributionsubstations, motors, transformers, generators andcapacitor diagram of the transition from a diffuse arc to a contractedarc in a vacuum of current and Voltage trends during a single phasevacuum interruption magnetic field contact arrange-ment with a rotating vacuum overanode , VoltageArc voltageShort-circuit currentinterruptionContactseparationReco very Voltage (system frequency)TimeTransient recovery Voltage (TRV) (high frequency) Individual tests.

10 Insulation of the main circuitswith Voltage at power frequency, auxiliary circuitand operating mechanism insulation, measure-ment of the main circuit resistance, mechanicaland electrical safetyThanks to the complete range of mechanical andelectrical locks, it is possible to construct safedistribution switchgear with the VD4 circuit-breakersThe locking devices have been studied to preventincorrect operations and to inspect the installationswhilst guaranteeing maximum operator Voltage1) kV 12 Rated frequency Hz 50 - 60 Rated normal current A 630.