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I am selling the following books and reference materials. All items' condition is like-new. 1. Electrical Machines, Drives and Power Systems (6th Edition) 6th Edition [Theodore Wildi] - $104 2. Power System Analysis and Design, Fifth Edition 5th Edition [J. Duncan Glover, Mulukutla S. Sarma...

I understand that the "average power consumption" is just the area under the curve (graph). 1 square = 25 kW Time interval 1: 25kW Time interval 2: 25kW + 25kW (0.5) = 37.5 kW Time interval 3: 25kW + 25kW + 25kW (0.5) = 62.5 kW Time interval 4: 25kW + 25kW = 50kW But for " "Max Demand at...

I read the solution but I don't understand how to get the "Max Demand at Start of Interval (kW). Please advise. Thanks,

I also need help on this one. Could you confirm my diagram (attachment) is correct? Thanks!

1) Could you confirm my calculation (attachment) is correct? 2) I understand that the question doesn't ask about the angle. But if I set Van at angle 0 deg, should the In (neutral current) at angle -86.57 deg? Notes: a) I also think that current conjugate should be considered (for single...

@Zach Stone, P.E. Thanks for the help!

@Zach Stone, P.E. I am working on Fault Current Analysis quiz question 9 at electricalpereview.com. And I am trying to use PU method to solve it. Set Vb=4160V, Sb=1.5MVA Zg, pu (Zpu at generator) = 0.079 pu * (1.5MVA/50MVA)=0.00237pu Zx, pu (Zpu at transformer) = 0.075pu Since Zg, pu is...

@Zach Stone, P.E. Could you help me with this one? + In your website electricalpereview.com Video Example 8 - Generator and Transformer Per Unit Method, it seems like you also ignore the whole "voltage base old and voltage base new" term. Zg,new = 5.6% (20MVA/55MVA) = 0.0206 pu Are the...

@Zach Stone, P.E. Thanks!

Question: Does the transformer contribute to the fault current in this case? If yes, why and how? Thanks!

This is from Fault Current Analysis quiz at http://www.electricalpereview.com. @Zach Stone, P.E. The fault is between the generator and the transformer. Does the transformer to the fault current? If yes, why? My solution: Since the fault happens at the upstream of the transformer, only the...

I am trying to use the MVA method. Sg = 200MVA/.25 = 800MVA Stx1 = 200MVA/.12 = 1666.7 MVA Since they are in series, treat them as resisters in parallel circuit. S=((1/800MVA) + (1/1666.7))^-1 = 540.5MVA Isc = S / sqrt(3) * V = 540.5 MVA / sqrt (3) * 230kV = 1356.8 A Graffeo's answer is I...

Sorry to hi-jack your question. I also have other questions now. 1) For transformer#2 new pu impedance ZT2, should the Vbase-old be "115KV" instead of "28KV"? So the equation should be ZT2= 0.09 (100MVA/105MVA)(115KV/28KV)^2. 2) The Zbase for the transmission line. Zbase=0.18(vbase^2/sbase3p)...

I think I understand. Since the given line voltage Vab doesn't have an angle, I can set the phase voltage Van at angle 0 deg. Then, the line voltage Vab will be 480 V at angle +30 deg. Ia (phase current) = S (single phase) / Van (phase voltage) 25KVA / 277 V = 90.2A And since this is wye...

"I am talking about voltage phase shift with Wye connection and current phase shift with Delta connection. Not the angle between voltage and current. If you compare Vline with V phase in star than V line is sqrt3 times Vphase and is 30 degrees ahead of Vphase. ( Drwa the vectors to find pout)...

 Maybe I should be more clear. I am talking about voltage phase shift with Wye connection and current phase shift with Delta connection. Not the angle between voltage and current. My understanding: (the followings are vectosr (magnitude with angle)) For Wye connection, V (line-line) = V...