The circuit shown is meant to supply a resistive load $${R_L}$$ from two separate $$DC$$ voltage sources. The switches $$S1$$ and $$S2$$ are controlled so that only one of them is ON at any instant. $$S1$$ is turned on for $$0.2$$ $$ms$$ and $$S2$$ is turned on for $$0.3$$ $$ms$$ in a $$0.5$$ $$ms$$ switching cycle time period. Assuming continuous conduction of the inductor current and negligible ripple on the capacitor voltage, the output voltage $${V_0}$$ (in Volt) across $${R_L}$$ is __________.

The single-phase full-bridge voltage source inverter $$(VSI),$$ shown in figure, has an output frequency of $$50$$ $$Hz$$. It uses unipolar pulse width modulation with switching frequency of $$50$$ $$kHz$$ and modulation index of $$0.7.$$ For
$${V_{in}} = 100\,V\,\,DC,\,\,L = 9.55\,\,mH,\,C = 63.66\,\,\mu F,$$ and $$R = 5\,\Omega ,$$ the amplitude of

A 50 Hz generating unit has H-constant of 2 MJ/MVA. The machine is initially operating in steady state at synchronous speed, and producing 1 pu of real power. The initial value of the rotor angle $$\delta $$ is $${5^ \circ }$$, when a bolted three phase to ground short circuit fault occurs at the terminal of the generator. Assuming the input mechanical power to remain at 1 pu, the value of $$\delta $$ in degrees, 0.02 second after the fault is _____________

A sustained three phase fault occurs in the power system shown in the figure. The current and voltage phasors during the fault (on a common reference), after the natural transients have died down, are also shown. Where is the fault located?