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#1
Start by
abhishek sharma
12-16-2013 10:23 PM
what is the difference between transient recovery voltage and restriking voltage
what is the difference between transient recovery voltage and restriking voltage
12-17-2013 12:49 AM
Top #2
Alan Maltz
12-17-2013 12:49 AM
Abishek,
Those terms are clearly defined in documents/standards from IEEE, IEC, BS, and probably IS as well. As a student you should have access to them for free. Do your own research/homework and you will not only know their definitions, but their derivation and proper usage. You will become a better student and engineer for your efforts.
Alan
12-17-2013 03:09 AM
Top #3
Raymond Lee
12-17-2013 03:09 AM
In a nut shell; during a fault goes up, voltage go down.
Current interruption occurs at zero crossing. Restrike occurs as the contact separates due presence of restrike voltage on the unfaulted side of the breaker contact as its voltage tries to recovers.
If or when current is successful on the zero crossing you get transient voltage recovery with lots of high frequency component. Voltage peaks are dependent on X/R of the system.
12-17-2013 05:25 AM
Top #4
abhishek sharma
12-17-2013 05:25 AM
thank you alan for your suggestion. restriking voltage occurs at the contacts of CB at instant of arc extinction whereas recovery voltage appears after final oscillation has died out after final interruption so iam confused and thinks that TRV and restriking voltage are same thing please clear that doubt.
12-17-2013 07:35 AM
Top #5
Olivier Bouilliez
12-17-2013 07:35 AM
TRV is the voltage that is created between the contacts of the breaker after the current interruption of short circuits .
As short circuits are mostly inductive (it is the impedance of the circuit that limlits the short circuit current more than its pure resistance) , the zero current apperas close to the maximum voltage on the 50 or 60 Hz wave.
Just after the zero of current, the upstream voltage of the breaker will continue its 50/60Hz wave.
On the other side of the contact, the downstream voltage will very quickly go down to zero , generally with a high frequency oscillation which will be given by the discharge of the downstream capacitances (even a cable or a bar has a capacitance to earth) .
The difference of voltage between the upstream voltage (a 50/60Hz vave) and the downstream voltage (high frequency frequency ) is the TRV (Transient Recovery Voltage) that is applied between contacts.
Now, if the contacts are not separated enough, or if the media between contacts has not enough dielectric withstand, an arc may appear again between contacts due to the TRV, this is called a restrike .
Following the restrike, there are high frequency oscillations (re-charging the downstreams capacitances) with high frequency low ampacity current that may be interrupted again .... and may cause again restrikes, that are named successive restrikes.
This, and many more details and diagrams, on
http://www2.schneider-electric.com/corporate/en/products-services/technical-publications/breaking.page?
I recommand : vacuum switching , or MV breaking techniques.
