Parallel transformers in ETAP

[matt111111]

Hi I am trying to connect two transformers in parallel using the electrical modeling program ETAP but I keep getting an error:

A loop condition has been detected for Panel2 and its downstream elements.

I assume this means there's a ciculating current ?!?

 

[nawao]

Both transformers belong to the same vector group?, in other words the phase shift is the same through each?

 

[matt111111]

Both transformers have the std positive seq, -30 degree secondary phase shift

 

[nawao]

How are controlled the tap changer positions?

 

[matt111111]

I have not modified the tap positions of the transformers. I have left them as there default values of 0 % tap on both the primary and secondary

 

[matt111111]

Is it not possible to supply two tranformers in parrallel from a panel using two different breakers?

My set up works fine when I supply the parallel transformers directly from the utility but when I supply them through the panel I get the error saying a loop condition has been detected

 

[davidbeach]

Maybe you need to have separate secondary busses for the transformers, then have very low impedance connections from those busses to the common secondary bus.

 

[matt111111]

"Maybe you need to have separate secondary busses for the transformers, then have very low impedance connections from those busses to the common secondary bus. "

I tried this out but still seems to give the looped condition

 

[bortix111]

My suggestion is contact ETAP technical support. They should be able to help you resolve the issue. I have been using ETAP for several years. Its tech support engs. are very good resolving my questions.