Figure below shows the plot of Fault distance vs voltage sag magnitude with and without a local generator.

Explain the reason for

a) Variation in voltage magnitude with respect to the fault location and

b) Difference in voltage magnitude for a system with a local generator and without a local generator.

30.8 Voltage Sag Magnitude (pu) 0.6 0.4 0.2 5 10 15 20 25 Fault distance (km) 30 35 40 With local generator Without local generator 45 50