Question 1. (a) A short 3-phase 11 kV line delivers a load of 4.1 MW, 2.6 MVAr lag. If the series impedance of the line is (72 + j12.1)Ω/ph, calculate the sending end voltage and load angle.

(b) Develop the receiving end performance chart for the above line and load to a 3-phase power scale. (Use a scale of 10 nun = 1000 V and 30 mm = 4.1 MW)

Question 2. Using the chart you produced in Question 3, determine: (a) the real and reactive power when

(i) the transmission angle remains unaltered and the sending end voltage is increased by 28%

(ii) the original sending-end voltage is reduced by 15% and the transmission angle increased by 9°. (Use the same scale as that for Question 3 (b))

(b) the real power limit for the sending voltage in (ii) above (i.e. when reduced by 15%).