Switching of 11 kV capacitor banks through long length cables

[krisys]

We have to re-locate the existing two (2) nos. of 11 kV capacitor banks. Each capacitor bank has four (4) units (sub-banks) of 1.25 MVAR, thus totaling 5 MVAR. In order to regulate the power factor, these four sub-banks will be switched in steps. Each Sub-Bank will be switched through vacuum circuit breaker.

The present location of the capacitor bank is very close to the location of switchboard, from where it is switched. The distance between the switchboard and capacitor bank is about 25 mtr.

Now due to some reasons, it is required to relocate the capacitor banks away from the switchboard. The new location of the capacitor banks is about 800 mtr from the switchboard. Do you see any problem in re-locating the capacitor banks to far away location?

Will there be any resonance/over voltage/surge problems due to cable capacitance? What kind of evaluations would be required before clearing the decision to relocate the capacitor banks to 800 mtrs away from the switchboard?

Your valuable feedback is appreciated.

 

[davidbeach]

Are they presently switched in steps? If not you need to consider the implications of back-to-back switching. Your cables may help, or maybe not. Using purpose built cap switchers may give better results than use of a general purpose breaker.

 

[krisys]

Yes, presently they are switched in steps.