Dear All.
Im so sorry, Im open new thread with more or less same name.
Zigzag grounding transformer make me crazy .
Data of zagzag transformer (about 20 years old).
Data from transformer ( sent me by mobile, from site )
S=2078kVA
I rated= 150A
I rated for 3 hours=181A
Short circuit in neutral 1500A for 5sec.
Impedance per phase in Ohm 27.8.
Rated voltage 24kV
according to my understading, max ZS current is
24/1.73/27.8=499A, same calculation as for NGR.
2078/24/1.73=150A it's neutral rated current
But what is 1500A for 5 sec, simple 3-ph symetrical short circuit to ground 3x500A??
Thanks in advance
Im so sorry, Im open new thread with more or less same name.
Zigzag grounding transformer make me crazy .
Data of zagzag transformer (about 20 years old).
Data from transformer ( sent me by mobile, from site )
S=2078kVA
I rated= 150A
I rated for 3 hours=181A
Short circuit in neutral 1500A for 5sec.
Impedance per phase in Ohm 27.8.
Rated voltage 24kV
according to my understading, max ZS current is
24/1.73/27.8=499A, same calculation as for NGR.
2078/24/1.73=150A it's neutral rated current
But what is 1500A for 5 sec, simple 3-ph symetrical short circuit to ground 3x500A??
Thanks in advance