Voltage equation for Dc shunt generator, Eb = V + Ia*Ra V = Ish*Rsh Ish = 200/100 = 2 A Eb = V + Ia*Ra 20 = Ia*Ra Ia = 20/0.2 = 100 A I = 100 - 2 = 98 A
Buchholz relay is used for protecting transformer against incipient or internal faults. Buchholz relay is a gas-actuated relay installed in oil immersed transformers for protection against all kinds of faults.
The ratio of full load current to short circuit current = 1/6 Xsc = j/(1/6) External reactance required = j*((1/6) - 0.06)) = j*0.106 pu Full load current = (40*1000)/(√3*15) = 1539.6 A Per unit reactance = j*0.106 = (I*Xr)/V j*0.15 = (1539.6*Xb)/((15/√3)*1000)) = 0.60 ohm
EXAMIANS