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I am using these formulas . Is it right to use these ones or do you have other way to calculate these resistance and reactance values? Zb=(Ub*Ub)/Sb where Ub:154 kV Sb:110 MVA R1: (Psc*Un*Un)/(2.Sn*Sn) ohms R2=R3=2R1 R1_2= R1+R2 R1_3= R1+R3 R2_3= R2+R3 R1_2(Per Unit)= R1_2/Zb Thanks...

Hello everybody, I need to calculate %R+ resistance and %X+ reactance values of primary-secondary, primary-tertiary and secondary-tertiary windings. Transformer information : 120/60/60 MVA 154/11/11 kV Uk: 16%/16%/16% Po: 40 kW Pk: 400 kW Io: %0.25 Please send your calculation results...

Hi Raghun, I plan to use zigzag grounding at D side of main transformer and hybrid grounding at generators. What do you mean by "It is also important to ensure that only one earth connection is in service at any given point of time in the MV system.". ?f i only ground generator neutrals then...

Thanks Slava

Hi Slava, 1. I have 154/11 kV YNd TR and a generator connected at 11 kV side. And other set of TR and generator is coupled in 11 kV side with a bus coupler. 2. Generator side is 11 kV 3. Conditions: a. Two transformer and two gen parallel b. One TR and one gen parallel with coupling open...

We have 2*62.5 MVA Transformer, 2*12 MW Generator and lots of big motors and loads in our power plant. Transformers are YNd,generators are connected to D side and we are discussing about grounding of generators. Should we use hybrid, solid or high resistance ground for generators? Or should we...

Thanks Scotty

Hello everybody, What is the rule and limitations of chosing TR vector group. For example i will use a YNd transformer %6 Uk 33/0.4 kV but i don't know which vector group to choose. YND11 or 1 0r 5 ? Thanking you in advance

Hello everybody, I have 132/6.6 kV 40 MVA YNd11 main transformer and 250 kVA ZNyn1 Auxilary Earthing transformer connected to main transformer at 6.6 kV side. I'm trying to calculate the earth fault current values but i calculate only 3 amps.But when i use a zigzag grounding instead of ZNyn1...