Hello ALL,
This question is succession to my earlier question regarding reclosing. I appreciate the input.
On my 27 kV system, station bus has a fault 3 ph fault of 631 MVA, approx. 13000 A. The feede is a mix of O/H and U/G, run of 6000 m. Fault at customer main incoming primary 27 kV...
Hi All,
I am programming a GE relay for a new feeder in a 27 kV station. feeder length is approx. 7 miles. Approx. 3 miles of feeder length is underground cable and rest is overhead line.
Is there a thumb rule that can advise for this feeder not to have reclosing because approx. 50% of...
After reading replies to these posts, I wonder how come my utility has a 115 kV/27.6 kV system grounding with a 1.5 ohm resistor on the secondary side and then coming out of staton 27.6 kV, an O/H 27.6 kV feeder supplies pole top distribution transformers and I think may be they are single phase...
Hello,
"I aplogize for not being very much specific in the information here."
I need some input into understanding my responsibility as an engineer and vendors responsibility who is supplying the equipment.
I am planning to buy a arc rated switchgear for a "X kV" voltage. For testing...
Hello All,
I am buying a 4.16 KV swgr fed by two incoming XFRM's rated 5 MVA, 27.6 kV/4.16 kV. Both will operate in parallel with no tie.
Voltage= 4.16 kV
TR1= 5 MVA %Z1= 5
TR2= 5 MVA %Z2=5
Short Circuit Contribution MVA(TR1)= 20 P.U.=13895 A
Short Circuit Contribution MVA(TR2)=...
ohagan...
I have used WinIGS and there are few things this software interprets Neutral and Ground.. in a different fashion...
u can send ur model to Sakis and analyze this on the phone with him... I have done it few times and he was very helpful....
besides that there are grounding gurus...
Hello,
I have done my homework well before asking this questions and also read posts here as well. Because, I am not an expert so need your final opinion,
Q#1 Why in most of the cases, we d'nt consider DC offset value of current in to calculation when the whole point of calculating...
Thanks Alehman. I just have to pick up pieces of some body who did not do a diligent job picking up the XFRM size in the past. I am sure, studying trip units again will give me a better handle on the situation. I was probably cutting corner by asking trip question. I have done a quite a bit of...
Thanks Alehman. I apologize for lacking clarity in my question. Yes there are two sources, which will feed same panel in case of transfer.
1. Use of Molded Case CB- Eaton has MCCB up to 2500 A, Based on your experince a Power circuit breaker should be a the way to go. Would that not be more...
Hello,
I truly beleive in" If you dont use it you loose it".
For the last one year, I have started working for a utility and working on 27.6 kV and onwards, I completely forgot how to set a molded case circuit breaker, which I used to know everything about. 120/208 V panels are the last thing...
Auslee,
Sorry for jumping in your post.
Thanks for your response Jghrist and EddyWirbelstrom.
1. In Stations those have a Delta secondary or a floating star connected secondary leaving the station and then a fault occurs down the line, and if there is no ground return, Line breaks and hands...
I have a questions for the experts here. Suppose the primary is 115 kV Delta and Secondary is 44 kV with solidly grounded star connection.
Three O/H line leave the station with a ground underneath the three wires and no neutral. Dont you think in that case if a fault occurs 1 KM down the line...
Bravo RCWilson,
You had me for a sec. while I was reading this post and I said to my self How you can come to 37.5 kV but you infact were alluding to the misnomer.
I actually myself learned grounding from this post. You and Jghrist had contribution towards it. I recall reading your posts...
Hi,
I had posted a similar post in the past as well. Unfortunately, I have not been able to find proper litrature issue on this subject. I am sure, some of you have come across this and will be able to advise me some useful input.
1. Partial discharge or Corona test= Is this traditionally a...
