I have a substation transformer question and would like to get other people’s opinion or current practice on the subject.
We have several substations with 115kV to 12.47kV transformers that feed a set of switchgear. Some of these stations have 2 transformers, which is where my question comes...
A coworker in our generation engineering department recently experienced this problem so I thought I’d check on here for some ideas for him, I’ll try to be brief, let me know if you need more information.
We had an 11.5kv, 9MW hydro unit out for 2 weeks of scheduled maintenance. During this...
Here is my system data:
V = 12.47kV
Isc = 8.338kA
Ia = 8.12kA
D = 914mm (36")
t = 1.1 seconds
G = 152mm (~6")
Using the IEEE 1584 equation in 70E I get an incident energy of 11.3 cal/sq cm
Using the theoretical equation [D.8.4] in 70E
I get an incident energy of 70 cal/sq cm
How can they be...
I've been reading this forum since I got out of school (about a year ago). I've learned alot from everyone here, hopefully I can start contributing as I become more competent in the power field, for now I have a question I would like advice on. Recently we had a main breaker trip on...
If I have the short time delay on a LV molded case circuit breaker set at .1 seconds, is this the total amount of time it will take the breaker to open? Does the .1 seconds include breaker operating time or is it just a delay before the breaker starts to operate?
