Capacitor bank requirement
Capacitor bank requirement
(OP)
Hi everyone,
I am Raja, i have some technical doubts ,i am working in 33/11 KV substation with 3 20 MVA(33/11.5KV) transformer
1) 11KV SWG SEC-A,SEC-B & SEC-C (three incomer & 2 Bus section scheme)
2) 5 MVAR capacitor bank for each 11KV SWG( SEC-A,SEC-B & SEC-C)
My doubt when incomer-1 in off condition bussection-1 closed and incomer-2 feeding the load of SEC-A & SEC-B ,so in this condition for power factor correction capacitor bank -2 is enough to connect in the bus or capacitor bank-1 also need to be connected to the bus?
please clarify the above issues
Thanks & Regards
Raja.P
I am Raja, i have some technical doubts ,i am working in 33/11 KV substation with 3 20 MVA(33/11.5KV) transformer
1) 11KV SWG SEC-A,SEC-B & SEC-C (three incomer & 2 Bus section scheme)
2) 5 MVAR capacitor bank for each 11KV SWG( SEC-A,SEC-B & SEC-C)
My doubt when incomer-1 in off condition bussection-1 closed and incomer-2 feeding the load of SEC-A & SEC-B ,so in this condition for power factor correction capacitor bank -2 is enough to connect in the bus or capacitor bank-1 also need to be connected to the bus?
please clarify the above issues
Thanks & Regards
Raja.P






RE: Capacitor bank requirement
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Capacitor bank requirement
Make sure your switchgear has been type tested and assigned a rating for back to back capacitor bank switching. Not all manufacturers type test for that duty.
Regards
Marmite
RE: Capacitor bank requirement
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Capacitor bank requirement
As noted by Marmite, there may be problems when one bank of capacitors is switched on when the other is already on (back-to-back switching). Energizing the second bank will create a switching surge that may exceed the capabilities of the switch (or tie breaker - whatever is energizing the second bank).
You also may be creating a resonant harmonic condition by putting both banks on one transformer.
These things need to be investigated.
RE: Capacitor bank requirement
Capacitor bank Auto Power Factor Controller CT input selection
1) Capacitor bank-1
a) If I/C-1 CB closed R-phase of the CT will come to summation CT of APFC
b) If I/C-1,B/S-1 & I/C-2 closed R-phase of I/C-1 & I/C-2 will come to summation CT of APFC
c) If I/C-1 open and B/S-1 & I/C-2 closed R-phase I/C-2 will come to summation CT of APFC
d) If I/C-1 & 2 open B/S-1 ,B/S-2 & I/C-3 closed R-phase I/C-3 will come to summation CT of APFC
e) If I/C-1,2,3,B/S-1 &B/S-2 closed R-phase CT I/C-1,2 &3 will come to summation CT of APFC
RE: Capacitor bank requirement
I need your attention on the drawing which i sent u in the above attachment
Incomer-1 ,Incomer-2 & Incomer-3 R phase CT they connected to the capacitor bank-1 Auto Power Factor Controller through auxiliary contact multiplication with the condition of Bus section & incomer combination.
Incomer-1 ,Incomer-2 & Incomer-3 Y phase CT they connected to the capacitor bank-2 Auto Power Factor Controller through auxiliary contact multiplication with the condition of Bus section & incomer combination.
Incomer-1 ,Incomer-2 & Incomer-3 B phase CT they connected to the capacitor bank-3 Auto Power Factor Controller through auxiliary contact multiplication with the condition of Bus section & incomer combination.
Please comment your advice regarding the above scheme is reliable or not?
RE: Capacitor bank requirement
RE: Capacitor bank requirement
the following are the details i have in the drawing
Rated output =5MVAR
No.Of Stages =5
Stepsize =1
Rated voltage =11500V
Insulation level =28KVrms
Each capcitor stage contains the following
Air cor damping reactor 250uH,53A
6 no's 201.7KVAR,7303volt internally fused capacitors connected in UN-grounded double star