SF6 and vacum breakers
SF6 and vacum breakers
(OP)
what is the differnce in costs ,operation and maintenance ?
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RE: SF6 and vacum breakers
advantages of SF6:
Softer switching than vacuum breakers, meaning that less pronounced voltage peaks are caused when interrupting large currents.
Suitable for voltages up to 66kV for metal-clad switchgear and 800kV for GIS
SF6 gas pressure can be easily monitored
Insulating medium present no fire/explosion hazard.
disadvantages of SF6
Depositories formed during switching limit the number of achievable operations before maintenance/refurbishment is required
More expensive than other types of switchgear.
Not environment friendly
May pose a health risk to human beings in that it may cause suffocation to unaware workers (if it leaks)
advantages of vacuum:
Due to virtually no depositories being formed during the breaking operation, vacuum support a large number of operations
More compact than other breakers
Vacuum bottles are relatively inexpensive and easy to replace.
disadvantages of vacuum:
Tendency to cause voltage spikes when interrupting large currents.
No practical method available at this stage to monitor the vacuum inside the bottle
Generally limited to voltages of up to 36kV.
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RE: SF6 and vacum breakers
In HV application above 38 kV, SF6 virtually dominating the interrupting technology today.
Here is more about comparison between SF6 and vacuum interrupters.
http://www.panickker.net/article6.htm
RE: SF6 and vacum breakers
RE: SF6 and vacum breakers
How often the breaker is operated?
Based on several CB performance reports, the number of Closed-Open operations favors the VCB over the SF6 counterpart.
Probably the concern of vacuum monitor referred in your post is magnified from previous reports in old VCB designed in early 60’s. Appears this is not longer a problem since the failure rate of today's VCB is so low that loss of vacuum made difficult to justify its development.
RE: SF6 and vacum breakers
RE: SF6 and vacum breakers
Did you check with the manufacturer to verify this operation mode?