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| Utility Modeling for arc Flash study https://brainfiller.com/arcflashforum/viewtopic.php?f=13&t=99 |
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| Author: | Sujit [ Wed Mar 26, 2008 9:46 pm ] |
| Post subject: | Utility Modeling for arc Flash study |
hi friends, i am on the job of Arc Flash study of 1 industrial setup. The given fault values contains max & min values & cooorosponding X/R ratio as mentioned below: Utility Fault levels are given with following details: Supply voltage : 440V Freq:50 hz Utility Fault level : 3 phase :- Max : 13kA , Min : 8.6kA 1 phase :- Max : 8.8kA , Min :1.9kA X/R Ratio : 3 phase :- Max : 3.62 , Min : 0.329 1 phase :- Max : 3.31 , Min : 0.22 So, my questions is, how to model the utility for Arc Flash studies? Is it required to model two utilities with 1 with max fault level & 1 with min fault level & corrosponding X/R ratio ; one is operating at a time. Please advise? |
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| Author: | Homerjs78 [ Fri Mar 28, 2008 3:19 pm ] |
| Post subject: | |
Your software may allow you to model the system for both scenarios without requiring you to model the system twice. If you use the IEEE 1584 equations, there is a built in (reduced fault current) check that will evaluate 100% and 85% of fault current. If you model both the high and low estimate at both 100% and 85%, you will have a sufficient analysis. I don’t know if this is an option in all available software packages but this is an option in the Easy Power software. |
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