How to choose surge capacitor? 1

[jyj982001]

I notice that there are surge capacitors eqiupped in ABB GCB(generator circuit breaker) cabinet.Could anyone tell me how to choose surge capacitor? Such as how much value of the surge capacitor shoud be chosed based on the circumstances.
Thanks in advance!
For the basic information of surge capacitor,we can find from ABB webite.

 

[odlanor]

See Westinghouse-Electrical Transmission and Distribution Reference Book chapter 18- VII surge protection for rotating machines.

See

http://www.lake-shore-electric.com/catalog files/04720 Generator Surge Protector.pdf

Some manufacture of generator circuit breaker(as ABB) include generator surge protection in the CB cubicle.
Capacitors are applied for surge protection and to improve perfomance of CB during Transient Recovery Voltage.

 

[jyj982001]

Thanks you.
I download the pdf file. I find that the selection of the capacitor only relates to the voltage in thi file.
But I find there are different values for the surge capacitor with same rated vlotage in ABB relative documents.
Then how to choose the value for those with the same voltage?

 

[odlanor]

See attached Protection_of_rotating_machines.pdf.
Remember:
1- generator effectively grounded must has neutral resistance of 50 ohms or less.
2- In table 3-I lightning arrester rating , when applied to OZn lightning arrester, refers to MCOV.
For instance , a lightning arrester of 15kV rating refers to a OZn surge arrester of 18kV rated(duty cycle) with 15kV MCOV.

 

[edison123]

If you're asking about their capacitance, it is usually same as the generator stator windng capacitance per phase.

Muthu

http://www.edison.co.in

 

[edison123]

Nice links odlanor. Thanks.

Muthu

http://www.edison.co.in

 

[jyj982001]

odlanor ,it's so nice of you to give this help!