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Let me rephrase the original post in electromagnetic terms: Suppose we impress Vab (3 ph source) to both H1-H2 terminals of the above 1ph tx and 3ph tx so that they are in parallel. The X1-X0 will be in phase with H2-H1 phasors on both transformers so that both X0 terminals can be grounded at...

rbulsara (Electrical) Jan 21, 2005 wrote: I a bit unclear what you are saying. I did u actually replace the single phase tx or just grounded one of the leg of 208V secondary? ****** *Replaced with a grounded leg ********** If it is a 2 winding 13.8kV/208V single phase Tx, it really does not...

Thanks Busbar. I don't have information on the replaced 40 years old transformer because I wasn't involved with the installation. But based on conditions at the other sites, it looked like a 3-wire 208V, 1ph secondary. The center tap was not grounded nor used as a neutral. The user load is a...

I was asked to look into a grounding issue inside a substation because of circulating ground currents. The incoming service is 13.8kV 3 phase, 3 wire. There are 4 step down delta-wye transformers with neutrals grounded to station ground. The problem is with a single phase 13.8kV-208V step down...

My company has the same problem. We replaced an oil filled transformer 5 years ago with a cast-coil type: 34.5kV Class 27.6-4.16kV step down, 750kVA, 150kV BIL outdoor environment- -20C when it failed. replacement cast coil flashed over to ground last spring, replaced core/coil assy and arced...

SidiropoulosM, I think it is unfortunate that an authority will only mandate reactive power margins after the collapse of the power system. Let us hope that NERC and N-E council(?) will follow and include reactive power margins to designate their system as stable. My utility, which also...

I toil for the building services sector and I have never worked for any utility. But back in the 80's we were doing studies on the steady stability of power systems and we were able to look at the '65 and '77 outages as voltage collapse in the steady state sense. Most of the discussions above...