Thanks jghrist,
You are exactly correct. The H0 and X0 are internally connected by a removable link. And the utility has already agreed to doing this versus giving us the transformer we want. So this would not be a typical grounded wye-ungrounded wye situation since H0 would be grounded on...
We currently have a 15kVDelta-480VDelta transformer feeding our plant. We ground the "B" phase of our 480V system so there are no fuses in "B" phase throughout the plant. The transformer failed and the utility wants to replace with Wye-Wye transformer. They plan to ground the HV neutral at...
I have an existing 500hp motor drivin through a VFD. There are parallel 500MCM cables. There is also a bypass contactor around the VFD. We plan to upgrade to 600HP motor. I can limit the output of the drive to 600HP. If I use the FLA of the new motor 680 x 1.25 then I need a cable good for...
Does anyone know of the following device. I was told that he saw a utility maintenance person use it. It is a hand-held device that checks for grounds or crossed phases on the secondary side of the transformer without haveing to disconnect the cables or grounds from the transformer.
Thanks all for your replies. Yes the information was from ABB directly and they had mentioned that they could service them, but I was still in need of some spares. Also, the zone interlocking function is required to maintain downstream coordination. Thanks again.
I have an installed base of ground relays with zone interlocking capabilities with no spares. I am trying to find some spares (about 20) to assist on swapping out during routine shutdowns. They are no longer manufactured by ABB. Does anyone know of a company that may sell/repair old relays...
We have a 2300V ungrounded system that we want to convert to a High resistance grounded system. Are there any advantages/disadvantage to using a zig zag transformer with a resistor in the neutral leg verses 3 single phase grounding transformers connected in Wye primay and broken delta secondary...
We have 3 8333kva 44kv-7200V single phase transformers connected in Delta primary and Wye secondary. We had a percentage differential relay operate and a dip on our system voltage. The transformers were broken loose and a TTR test was performed on each. Two nulled the meter at ratio the...
Does anyone have any experience with these companies that survey and evaluate your electrical system. The they make claims they can reduce your electric bill by installing some of their fixes. They range from power conditioners at the motor with P.F. capacitors, surge suppressors, light...
All of the comments stated are valid. We use both types depending on the application. One other item that has not been mentioned is the predective maintenance tests that can be performed on these transformers. The liquid transformer would allow online test (oil samples) and also additional...
