(a) Non-linear loads are used more often in modern day electrical power systems and these cause harmonics in the system network. In the aid of diagram, compare the fundamental frequency, the second harmonics and the third harmonics if the fundamental frequency is 50Hz, the frequency of the second harmonic is 100Hz, the third harmonic is 150Hz and the supply voltage is 240V. Based on the diagram, justify the harmonics phenomena. (b) Voltage sags pose a serious power quality issue for the electric power industry. Referring to Figure 1, a single-phase power system supplies a load which is 50km away from the source and the source impedance as well as the line impedance are 0.8? and 0.18?/km respectively. Assume the protection relay will trip at 90% of the supply voltage, determine the voltage sag at the point of common coupling (PCC) when the fault in the transmission line occurs: i. At a point 48 km away from PCC. ii. At a point 10 km away from PCC. (c) Compare the waveform of the voltage, 0.04s before and 0.04s after fault occurs as shown in Figure 2 for the line faults as in b (i). (d) Compare the waveform of the voltage considering 0.04s before and 0.03s after fault occurs for the line faults as in b (ii) and clearly show in the waveform when the protection relay will trip.