I need to model a generator for a load flow and stability study in the SKM software.
The generator (only one generator) is in parallel with the utility.
I plan to assign the utility as a SB source and the generator as a PV source.
I have all the detailed information about the generator.
Is...
The standard for MV General Purpose fuses establishes that the fuse should not oprate on currents that will make. The fuse open in more than one hour. The chalange i have is how to know this minimum allowable current.
The manufacturrer TCC’s plot the general purpose curve up to 300s or up to...
Thanks for the answer.
So that means that there is not an override built (open instantly) in the LVPCB's after the 30 cycles similar to the ICCB's that have a built in override?
Is there any manufacturer literature (from a specific LVPCB) I can read that explains what happens after the 30...
A LVPCB can be set or purchased without INST setting and according to IEEE C37 test, it can hold the short circuit for 30 cycles. What happens after the 30 cycles if the short circuit current is still present? Will the LVPCB open instantaneously, like an override? Or will still remain closed?
Actually not. I am interested in the negative sequence RESISTANCE because that is a parameter I have to enter in the SKM software to model the generator contribution data (ANSI FORMAT).
I am interested to know more about the negative and zero sequence RESISTANCE for small (i.e. 1 MVA) low voltage (i.e. 480V) STANDBY GENERATORS.
Is the negative sequence resistance equal or similar to the positive sequence resistance?
Is the negative sequence resistance typically a percentage...
I think I was not very clear in my question because I am getting good answers but not in the issue in question.
The specific question is the following:
When performing a load flow study (not a short circuit study or arc flash study) in SKM (and I assume isnthe same in all othe software) do you...
In SKM software, the Utility contribution is modeled considering the nominal voltage delivered by the Utility and a Thevinin Impedance.
For load flow calculations, SKM has an option to include or not to include this impedance.
If we include it, the voltage drop from this Utility Thevenin...
I was asked the following simple question that made me evaluate what I always thought a as a given.
When the NEC suggests in the informational notes to keep feeders and branches percent voltage drop below 3% and bus percent voltage drop below 5% is it with respect to the NOMINAL voltage of the...
Thanks so much for all your answers.
I checked the equations that magoo2 sent me. That is exactly what I wanted. Thanks so much.
Just before I opened your response, I read the IEEE Violet Book and also found the equations I needed.
I ended up using the equation 2.3 from the IEEE Violet Book...
I do not think that the x in the second equation (the sine equation) should be replaced by t in seconds. The sine equation is based upon radians.
But I could be wrong. If you have proof, can you send it to me so I can check it out?
Thanks.
I want to plot the DC Decrement curve with an Asymmetrical curve in the same graph.
According to IEEE Std. 141-1993 (Red Book, page 118) the formula for the DC Decrement curve is as follows:
DC Decrement = e^-(R*t/L). Converting the L to X/R with a frequency of 60 Hz, we have the following...
