- #1
Brad B
- 1
- 0
Hello everyone,
I'm no engineer, just a guy that works in the electrical industry. Today I was doing some substation switching on a 138kv shunt capacitor bank, which consists of 11 capacitors connected in parallel forming a group, then four of those groups connected in series per phase, making 44 total caps per phase. The three phases are then wye connected.
We were called out to repair said capacitor bank due to an imbalance lockout. Generally when this happens we find a single fuse has blown, we replace the capacitor and the fuse and away we go. Today we found that an entire group of 11 capacitors on one phase had blown their fuses, but the other groups on that phase were normal. We tested each capacitor, and they all seemed "normal", as in not shorted and capacitance matching nameplate values.
We refused all 11 and reenergized the capacitor bank and, yep, all 11 fuses blew. So, me being as green as I am, am not sure what would cause a single group to blow while leaving the rest of the phase untouched.
Anyone with any experience care to offer any insight? Anything would be appreciated.
Thanks very much.
I'm no engineer, just a guy that works in the electrical industry. Today I was doing some substation switching on a 138kv shunt capacitor bank, which consists of 11 capacitors connected in parallel forming a group, then four of those groups connected in series per phase, making 44 total caps per phase. The three phases are then wye connected.
We were called out to repair said capacitor bank due to an imbalance lockout. Generally when this happens we find a single fuse has blown, we replace the capacitor and the fuse and away we go. Today we found that an entire group of 11 capacitors on one phase had blown their fuses, but the other groups on that phase were normal. We tested each capacitor, and they all seemed "normal", as in not shorted and capacitance matching nameplate values.
We refused all 11 and reenergized the capacitor bank and, yep, all 11 fuses blew. So, me being as green as I am, am not sure what would cause a single group to blow while leaving the rest of the phase untouched.
Anyone with any experience care to offer any insight? Anything would be appreciated.
Thanks very much.