Surge Arresters and Surge Capacitors

[Kiribanda]

Hi all,

In most generator installations, we can see that both surge arresters and surge capacitors had been installed. Could any body throw some light about the application of these two different equipment in generator installations? (Any text book or IEEE technical paper to read?)

Thanks in advance

Kiri

 

[slavag]

Dear Kiri.
Please see attached link.
thread238-192962
Regards.
Slava

 

[power2020]

Surge Arrestor: Reduces the amplitude of the surge
Surge capacitor: Increase the slope (dv/dt)and frequency of the switching surge. Causes less surge impact on end connections of winding.

 

[cuky2000]

A sample of the IEEE surge withstand capability of a rotating machinery is represented in the enclosed link.

http://cuky2000.250free.com/Rotating_Machine_Impulse_Voltage_Envelope_IEEE.jpg

A simplify criteria to provide Surge protection is suggested as follow:
_ For any surges of either magnitude or rise time above the curve, wave-sloping capacitor should be provided.
_ If transient voltage above 1/3 level will be present, surge arrester should be provided.

Beware that for small unit the cost of surge arrester and capacitor will be difficult to justified.

 

[prc]

Surge capacitors have one more function.When it is connected to tertiaries of transformer windings, it helps in reducing the magnitude of the transferred surges from primary and secondary due to the extra capacitance .This way transferred surges can be limited below the BIL of tertiary circuit.