What is the correct method of calculating % overloading of a 3 phase line.
Export Overloads gives the correct overloading of 3 phase line? It just calculates the maximum current in three phases and divides it with normAmps?
Why this calculation is not for three phases i..e., sum of currents in all phases/ normAmps?
Thank you.
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Yes, this is the correct approach for calculating the overload of a 3 phase line.
The reason it does this is because the element that will begin heating up first (and as things progress, sagging more) is the conductor with the most current in it. It's just a single conductor that will be affected, first. The normal amperes is the maximum, normal, current that the conductor can carry as found in books and tables.
Hope this helps.
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Complementing Wes' answer, there is another method for getting a more detailed report regarding overloads, however, it requires your model to comply with some features:
There must be an energy meter at the feeder head of the circuit model.
The Demand Interval reports need to be enabled before starting the simulation using the following commands:
The solution needs to be either daily, yearly and for at least 24 hours since the DI reports are time based, it doesn't matter if you loads have no load shape linked to them. Don't forget to close the DI files. Something like this:
This will generate a sub-folder within your model's folder called "DI_yr_0". Look inside, you'll find a file called "DI_Overloads_1.CSV". This file contains the list of all the overloaded PDE (lines, Xfmrs, ...) and will report the overload level per phase in percentage and actual units. This report is intended to work per hourand will report the hours in which a particular PDE is overloaded.
Best,
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
What is the correct method of calculating % overloading of a 3 phase line.
Export Overloads gives the correct overloading of 3 phase line? It just calculates the maximum current in three phases and divides it with normAmps?
Why this calculation is not for three phases i..e., sum of currents in all phases/ normAmps?
Thank you.
Hi Kirn,
Yes, this is the correct approach for calculating the overload of a 3 phase line.
The reason it does this is because the element that will begin heating up first (and as things progress, sagging more) is the conductor with the most current in it. It's just a single conductor that will be affected, first. The normal amperes is the maximum, normal, current that the conductor can carry as found in books and tables.
Hope this helps.
Hello,
Complementing Wes' answer, there is another method for getting a more detailed report regarding overloads, however, it requires your model to comply with some features:
The Demand Interval reports need to be enabled before starting the simulation using the following commands:
The solution needs to be either daily, yearly and for at least 24 hours since the DI reports are time based, it doesn't matter if you loads have no load shape linked to them. Don't forget to close the DI files. Something like this:
This will generate a sub-folder within your model's folder called "DI_yr_0". Look inside, you'll find a file called "DI_Overloads_1.CSV". This file contains the list of all the overloaded PDE (lines, Xfmrs, ...) and will report the overload level per phase in percentage and actual units. This report is intended to work per hourand will report the hours in which a particular PDE is overloaded.
Best,
very helpful, indeed!
Thank you very much.