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Yes - the Transformers are solidly earthed, and the 3% difference was between the impedances. I'll give some consideration to not tripping immediately - the VT's should give the system a coupling to earth, though without earthing no earth faults would be detected, and if one were to happen...

I am looking to determine if there are any potential problems with operating two Zn Earthing transformers in Parallel ? They are connected to an 11kV system that is energised from 3 ungrounded 11kV generators. The earthing transformers are to the same design, but have slightly different zero...

Hi Alex Thanks for the post. Its a good way round, and if you use a negative torqe, you can speed up the start up ! I was doing motor starting by using the auto initialisation, with slip set to 100%, and putting in a current source at t=0 to counteract the torque set by the auto init routine...

Apologies for posting this on this site rather than the EEUG forum, but there seems to be more activity here ! Has anyone tried in ATPdraw to use the loadflow (FIX SOURCE) feature while at the same time using the Caged rotor induction machine (UM3) auto inititialize feature ? I'm seeking to...

Hi Alex, The new terminal that appears is to specify the torque device (Type 14 Current source) that the auto-initialization routine will adjust the magnitude of. I've just started modelling UM3 and thats the easiest way I've found. Also found that the Neutral must be connected to Earth...

Can anyone point me in the direction of a good resource on gas turbine modelling. I need to model a 30MW gas turbine in ATP for load shedding studies and am looking for block diagrams (and any TACS examples if I'm lucky !!!!) Thanks Matt

Hi gbk, I would like to get hold of the program that converts induction motor nameplate data to data that can be used by ATPdraw. I checked out the Japanese ATP site but could not find the program. Do you have a link for it ? It would be most helpful. Thanks Matt

I am modelling a 250 kVA diesel generator to estimate the voltage and frequency excursions that occur due to step changes in load. I have a good transfer function (G(s)) for the alternator, avr, exciter and will hopefully be obtaining one for the governor/actuator system. I do not have...

Does anyone know what the typical inrush magnitude and time to decay is for a shunt connected air cored reactor ? I would imagine it can be a maximum of 2 x rating as there will be no remenant flux, and will be over with pretty quick due to no iron to be magnetized. I'm looking at a reactor...