In the circuit of Figure 7.1, \(\mathrm{V}=277\) volts, \(\mathrm{L}=2 \mathrm{mH}, \mathrm{R}=0.4 \Omega\), and \(\omega=2 \pi 60 \mathrm{rad} / \mathrm{s}\). Determine 

(a) the rms symmetrical fault current; 

(b) the rms asymmetrical fault current at the instant the switch closes, assuming maximum dc offset; 

(c) the rms asymmetrical fault current five cycles after the switch closes, assuming maximum dc offset; 

(d) the dc offset as a function of time if the switch closes when the instantaneous source voltage is 300 volts.

Figure 7.1

Transcribed Image Text:

Generator 10 0 -10 20 10 0 0 -10 Eg Xg Transmission Line X R ww 0.05 0.1 (b) ac component 0.02 (a) Equivalent diagram of symmetrical fault 0.04 Isc 0 Fault -10 0 www 0.06 0.08 (d) Fault current Grid 0.05 0.1 (c) dc component 0.1 Vgrid 0.12