Three supply points A, B and C are connected to a common busbar M as shown in Figure 4.2. Supply point A is maintained at a nominal 275 kV and is connected to M through two 100 MVA, 275/132 kV, 7.5 % transformers and 132 kV lines of length 150 km, 0.1 Q/km. Supply point B is nominally at 132 kV and is connected to M through a 132 kV line of 100 km length, 0.1 Qkm. Supply point C is nominally at 275 kV and is connected to M by a 100 MVA, 275/132 kV, 7 % transformer and a 132 kV line of 50 km length, 0.1 Okm. The line diagram of the system is shown below. Calculate the magnitude of the VARS injection required at M to re-establish the original voltage if at a particular system load the line voltage at M falls below its nominal value by 5%. {Ans. 199.9 MVAR} 275 kV 132 kV M 100 km 0.1 Ohms/km 132 kV A HB 100 MVA 150 km 50 km 100 MVA 275/132 kV 0.1 Ohms/km 0.1 Ohms/km 275/132 kV X= 7.5% X= 7% 275 kV Figure 4.2. Schematic diagram of the system for Problem 4.2.