Recent content by katag

I have the book and took the course. I am on the fence. I am out of school 4 years and I didn't actually study Power in college, I was more e-mag and electronics. When I graduated I just happened to fall into a Power job. Love it. That being said, I was nervous about the test and wanted to take...

I understand that 3 phase faults are balanced faults and that when analyzing you can reduce to single phase. One NCEES 132 we use the equivalent impedance and the phase voltage to find the 3 phase fault current. On NCEES 513 and 530 we are asked for 3 phase short circuit current and use per unit...

I used Voltage Loop to solve this problem. We know that Vab = (R+jX)*IaA + VAB + (R+jX)*-IbB Vab = (5+10i) * 70<-20 + 12500 + (5+10i) *-70<-140 = 12954.6 which is closest to 13.0kV answer C. You just have to remember when you go around the loop that IbB is going the opposite direction of...

Thanks for the help. Makes sense now!

I came across this question in a practice test and don't understand the concept, nor do I have the actual solution, just the answer. What is the equivalent system impedance for a 3-phase fault at the high voltage bus of a 15/7.2kV transformer. The following information about the fault is given...

The phasor is V=(jXs)(Is) + Ei because it states that it is acting as a motor. If it were acting as a generator it would be V=Ei-(jXs)(Is). If you can find a picture of the equivalent circuit for a synchronous generator and motor then I think it will be more clear as it is just using Kirchkoff...

Do you have any of the books that people suggested as good resources? The Wildi book has good information on Autotransformers and a section on Power Electronics that has some info of VFDs. The Chelapati book also has good information on Autotransformers. The Wildi book is full of valuable...

I worked this test out today and got the same answer. I am using the 2011 NEC code and it seems that they may have changed that value from the 2008 NEC code because it is highlighted. This could be the answer with the 2008 version but I don't have it to verify. Either way I agree with your answer.

When using the MVA method for this problem and other problems we always do the calculations in 3 phase, right? I was reworking this problem and hesitated for a second because when trying to calculate the LINE MVA I wasn't sure whether to use V-LL or V-PH voltage because it deals with line...

To add to this, why is the 60kv Utility not included in the calcuation? I realize that there is not enough information given about the utility but I guess I am kind of comparing it to Problem 132 where the system impedance must be included in the calculation. In theory, doesn't the...

This thread is very helpful, I just wanted to bring it back for some clarification if possible. In the above post Flyer_PE you said that if there was another Generator "G2" in parallel with G1 and we wanted to know the contribution of just G1 we would completely ignore G2 and calculate the same...

You are correct! I calculated Zeq wrong and it all makes sense now. Thanks so much!

Just wondering if anyone can clear up some stuff about paralleling transformers. I was working on Complex Imaginary Exam 1 Question 62. The question gives you a total load current and the impedances of 2 paralleled transformers and then asks to solve for one of the transformers contribution to...

Thanks for the replies! Went ahead and got it!

I haven't been using this to study but just did a "look inside" on Amazon and it seems to be pretty comprehensive. To those that have this book, do you use it a lot? I know it is not that expensive I just don't want to overload myself with a lot of the same information in a bunch of different...