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Vacuum circuit breakers

Vacuum circuit breakers. Characteristics of vacuum circuits brakers: Up to 10 000 switching operation does not need maitenace High longevity and operational safety Non-burnable Without gas and flames emission Silent operation Low wear out Low hub of contacts

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Vacuum circuit breakers

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  1. Vacuum circuit breakers

  2. Characteristics of vacuum circuits brakers: • Up to 10 000 switching operation does not need maitenace • High longevity and operational safety • Non-burnable • Without gas and flames emission • Silent operation • Low wear out • Low hub of contacts • Very low arc voltage and extinguishing energy More at http://www.mikeholt.com/mojonewsarchive/EES-HTML/HTML/ElectricalCircuitBreakers~20030621.htm And : http://www.google.cz/images?hl=cs&gbv=2&rlz=1R2GGLJ_enCZ411&gs_sm=s&gs_upl=2891l2891l0l5031l1l1l0l0l0l0l172l172l0.1l1l0&q=Vacuum+circuit+breakers&spell=1&sa=X&oi=image_result_group&sa=X

  3. Application areas: • Short circuits currents disconnecting • Cables and out-door lines switching • Transformers switching • Generators switching • Motors switching • Switching of arc furnaces • Switching of trolley lines Transformer substation Transformátorová stanice Arc furnace Oblouková pec Trolley line And subsstation Podružná trakční stanice

  4. Principles of vacuum extinguishing chamber • Extinguishing of electric arc in vacuum • At contacts disconnecting arise electric arc created by metallic vapours separated from contact material. • Arc in vacuum has cone shape with top on cathode. Anode contact shape of the arc is big and enable temperature good spreading without overheating of anode surface. anode arc Magnetic pressure cathode Cathode spot Cone shape of arc in vacuum

  5. Under nominal current diffusion type of arc is established over all shape of electric contact. • When disconnecting current arises over nominal current, arc is by magnetic forces contracted on anode and cathode. Difussion arc Contaction on anode Contaction on anode and cathode Diagram of arc crossing from difussion to contractor type in vacuum chamber

  6. To increase breaker disconnecting ability anode spot must be eliminated. It is possible by means: • Contact material property • Contacts shape arrangement • By means of electro-dynamic forces rotate the arc bottom round the anode • Contact dimensions increasing • External magnetic field excitation Electrodynamic force Contact with rotating arc

  7. Contacts with radial magnetic field Spiral petal contacts

  8. To restrict over-voltage at low inductive currents disconnecting, chopped current must be minimised. • Low arc voltage, short time of arc relates to minimum arc energy and small contacts erosion => extinguishing system is maintenance free. Short circuit current Arc voltage Mains voltage Instant of current disconnection Time Contacts separation Restore voltage HF Transient recovery voltage Voltage and current time curve during one phase disconnection in vacuum chamber

  9. Vacuum extinguishing chamber Contacting ring Insulator valve Fixed contact Moving contact Shilding valve Corrugated sheet Linear bearing Electrical input and mechanical drive of movabvle contact

  10. Input terminal Vacuum chamber Output terminal Electric drive Insulating rod lever Operational principle of vacuum circuit breaker driving mechanism

  11. Construction of modern vacuum contactors Terminals of fix contact Drive of moving contacts Terminal of moving contacts

  12. Vacuum circuit breaker Siemens 3AH 1 Type 3AH1 maintenance fre • Durability: 10 000 switching operations • Applicaton area: from 7,2 kV up to 24 kV.

  13. Typ 3AH1– with lever drive of moving contacts Legend: 1) Upper holder of extinguishing chamber 2) Upper lead, 3) External brace 4) Vacuum switching chamber 5) Movable contact of switching chamber 6) Flexible conductor 7) Down holder of vacuum switching chamber 8) Down lead 9) Disconnecting spring 10) Pushing spring of contact 11) Třmen-Stirrup 12) Upper 13) Internal brace-Vnitřní vzpěra 14) Down supporting insulator - podpěrný izolátor 15) Páka –lever 16) Switching rod -Spínací táhlo

  14. Type 3AH3– Circuit breaker for high power applications Nevyžaduje údržbu, je extrémně výkonný a je schopen zvládnout až 10 000 spínacích operací. Typ 3AH3 se používá při velkých zkratových proudech do 63 kA a pro jmenovitá napětí do 36 kV. Vzhledem k vysoké výkonnosti je to ideální vypínač pro generátory a pro použití v průmyslu. Maintenance-free, powerful circuits breaker, ability 10 000 switching operations. Type 3AH3 usable up to 63 kA of short circuit currents and voltage 36 kV. With respect to high efficiency is determined for generator switching and industrial application

  15. Drives of vacuum circuit breakers Switching by means of spring energy accumulator

  16. Vacuum switch ABB VD4 • VD4 type switching poll creates complete fix maintenance-free switching unit • Extinguishing chamber is immersed into the peroxides-resin. • All system is pollution and dust resistant 1- Top terminal 2- Vacuum extinguishing chamber 3- Insulation cover 4- Moving contact pin 5- Bottom terminal 6- Flexible outlet 7- Moving contact compression spring 8- Insulating pull-rod 9- Fixing pole hole with thread 10- Connecting rod with hole for contact drive

  17. Typ 3AH3– varianta pohonu 3 driving mechanism No3 • Pohyb při spínání se přenáší přes spínací tyč (16) a páku (15) na pohonný dřík. Movement tranmission to the contacts over switching rod (16) and swipe (15) on driving shaft • Upper holder of switching chamber • Upper terminal • External spur • Vacuum switching chamber • Driving shaft of vacuum chamber • Flexible conductor • Upper holder of switching chamber • Lower terminal • Disconnectin spring • Contact pressure spring • Lug • Upper insulator • Internal spur • Lower insulator • Swipe • Switching rod Legenda k obrázku: 1) Horní držák spínací komory, 2) Horní přívod, 3) Vnější vzpěra 4) Vakuová spínací komora 5) Dřík pohonu vakuové spínací komory 6) Pružný vodič 7) Dolní držák spínací komory 8) Dolní přívod 9) Vypínací pružina,příp. přítlačná pružina kontaktu 10) Přítlačná pružina kontaktu 11) Třmen 12) Horní podpěrný izolátor 13) Vnitřní vzpěra 14) Dolní podpěrný izolátor 15) Páka 16) Spínací táhlo

  18. Table 1.Characteristics of the SF6 and vacuum current interrupting technologies.

  19. https://www.youtube.com/watch?v=XKzcrckw9Dk http://www.csanyigroup.com/comparison-between-vacuum-and-sf6-circuit-breaker http://www.ewh.ieee.org/soc/pes/switchgear/Presentations/DufMont.pdf

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