Hello,

Hoping you may be able to help.

I have two models, (the models need to be kept seperate for confidentiality), lets call them model A and B.

I am currently running arc flash calculations on Model B (have previously completed model A).

Model B is fed from a substation on model A, as such i have taken the fault level at the relevent sub in model A and used as a utility in model B.

i am unsure how to find the X/R ratio for the sub so i can transfer into the utility.

i have tried creating an X/R datablock and imported X/R LL, X/R Neg, X/R Pos, X/R SLG & X/R Zero. however all display 0.

even when i put a utility with an X/R of 8 onto a bus (i.e. no cabling or anything, therefore the X/R at the bus should be 8) it displays 0.

am i missing something? is there an easy way for me to find out the X/R ratio at the switchroom so that i can transfer into the utility of Model B


much appreciated for any info.

It may depend on your software. But for these types of projects, I usually look at the Short Circuit output report to find the X/R. I know it hows up there on both PTW and ETAP.

found it, i was looking at the wrong datablock i needed iec909 XoverR Neg/Pos/Zero