O/C Relay Settings For Arc Flash
O/C Relay Settings For Arc Flash
(OP)
We have a 4160-480V power transformers feeding 600V switchgears. These transformers are fed from a 4160 switchgear (switchgear #1).
Our Arc Flash levels are very high on the switchgear #2 480V bus. The 480V switchgear #4, the arc flash levels are high on both 'line' and 'bus'.
We have one GE F35 on each 480 switchgear incomer section and one GE MIFII on each 4160 outgoing feeders feeding the 4160-480V transformers.
We are planning to set the group 2 settings to instantaneous and name it as "maintenance settings".
For the 480V Switchgears that have high Arc Flash levels, we are going to run the arc flash with the F35 settings enabled to Group 2 and set O/C to instantaneous.
For the 480V switchgears with high Arc Flash Levels on BOTH 'line' and 'bus', will it help to set both the 4160V feeder and 480V incomer O/C to instantaneous?
If both are acceptable option, can we set the instantaneous P/U delay to 0.01 sec?
For the MIFIIs feeding the 4160-480V transformers, we are setting the P.U. delay to 0.2sec to overrride transformer inrush.
Hoping for your inputs based on experience...thanks
Our Arc Flash levels are very high on the switchgear #2 480V bus. The 480V switchgear #4, the arc flash levels are high on both 'line' and 'bus'.
We have one GE F35 on each 480 switchgear incomer section and one GE MIFII on each 4160 outgoing feeders feeding the 4160-480V transformers.
We are planning to set the group 2 settings to instantaneous and name it as "maintenance settings".
For the 480V Switchgears that have high Arc Flash levels, we are going to run the arc flash with the F35 settings enabled to Group 2 and set O/C to instantaneous.
For the 480V switchgears with high Arc Flash Levels on BOTH 'line' and 'bus', will it help to set both the 4160V feeder and 480V incomer O/C to instantaneous?
If both are acceptable option, can we set the instantaneous P/U delay to 0.01 sec?
For the MIFIIs feeding the 4160-480V transformers, we are setting the P.U. delay to 0.2sec to overrride transformer inrush.
Hoping for your inputs based on experience...thanks






RE: O/C Relay Settings For Arc Flash
"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg
RE: O/C Relay Settings For Arc Flash
Alan
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"It's always fun to do the impossible." - Walt Disney
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
Choose fast circuit-breakers. Their operation time must be taken into account when you calculate the arcing time.
RE: O/C Relay Settings For Arc Flash
The arc flash results in SKM was significantly reduced to Level 2.
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
QT is simply a additional trip setting that is enabled or disabled. If it did fail, the other settings in the trip unit would still apply. So the breaker would trip per the other settings, INST, ST< GF, LT, UB, etc...
Now if the entire system is not properly installed and tested in the first place the breaker may not trip at all.
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash
"Theory is when you know all and nothing works. Practice is when all works and nobody knows why. In this case we have put together theory and practice: nothing works... and nobody knows why! (Albert Einstein)
RE: O/C Relay Settings For Arc Flash
RE: O/C Relay Settings For Arc Flash