The turbine / generator manufaturer should be able to give you an idea of what amount of power the TG will pull under a reverse power (no steam) situation. On our newer machines we use a dual system that combines a contact from the stop valve with a timer and a reverse power relay with a timer...
We have two 6000 foot runs of 138 KV cable in the US that we put in about 10-12 years ago. The cable ran from a Utility 138KV station into our facility. It was expensive but gave us a way to get though an area that management did not want an overhead line running through for a variety of...
Look at the AB Chance Grounding stud - I've seen this used in US on switchgear at the cable connections for incoming or outgoing cable.
http://www.hubbellpowersystems.com/powertest/catalog_sections/PDF_hotline/3000_Grounding.pdf
Look at page 13 of the .pdf file (pages 3013 and 3014 of the...
As a follow up to Weimer42's comment "EC&M published a book explaining this method in detail entitled "Short Circuit Calculations - The Easy Way" by J.R. Seiver, P.E. and John Paschal, P.E. "
J.R. Seiver works (or worked) for Bechtel in Houston and I have a copy (somewhere)...
Jburn - IS the ground alarm system that you mentioned having on your subs a commercial system? If so, who made it? We have looked at designing our own as I have not found a commercial system. We just use the built in alarms for HRG equipped systems. I agree that an arcing fault can give very...
Comments to various posts:
We have a large number of ungrounded Wye 480 volt subs and a number of HRG equipped subs.
Question:
When you say 900 volts on the grounds - is this RMS volts to ground on the ungrouded phases? I have seen three instances (2 on a HRG Wye and one on a floating Wye)...
Allen Bradley has configuration software available on their web site - my guess is that Cutler Hammer (Eaton), GE, SQ.D, Siemens and others do also.
http://www.ab.com/software/pcp/
http://www.ab.com/software/pcp/downloads.html
ABB also makes a seed (vegetable) oil (BioTemp) transformer oil that competes with Cooper's Envirotemp Fluid. Both would be considered less flammable per the current NEC.
In the 80's and early 90's we put in a lot of VPI and VPE outdoor dry's (13.8 KV primary, 1000-2500KVA AA with Fans). Due...
There are a number of manufacturers of phase converters - one is RONK - www.ronkelectrical.com/pages/home.html. They are often used on farms where only single-phase service is provided.
We have a number of 1000 to 2500 KVA 480 volt subs with high resistance groundings systems on them and have had good luck with the "low range, big jaw" ammeters in finding the ground faults. The ground currents do split up along the many return paths but we have almost always been...
I've used a lot of tape shielded 5 and 15 KV cable in resistance grounded MV systems - they work fine as long as the tape is heavy enough to handle the ground fault current magnitude for the time it takes to clear the fault. Kerite, Okonite, Pirelli etc should all be able to provide their cable...
You might try the ELFT01, ELFT01D document listed on the http://www.pip.org site. It was designed for use in indutrial power systems. I would also look at the NETA forms as proposed by robertb.
"Floating" neutrals is one sense are common in older industrial sites in the US. 480 volt wye systems (powered by something like a 12.47/.48 KV delta wye transformers with no intentional connection of the wye to ground are common where there are three phase motor or transformer loads...
