Solved Examples
Example 2.1
Example 2.2 Draw the per unit reactance diagram for the power system shown fig below. Neglect the
resistance and use a base of 100 MVA, 220 kV in a 50 Ω line. The ratings of the generator, motor and
transformers are as follows:
Figure Single line diagram of Example 2.2.
Figure: Reactance diagram of power system of
Example 2.2.
Example 2.3
Draw the reactance diagram for the power system shown fig below. Neglect the resistance and use a base of
50 MVA and 13.8 kV on generator G1
Figure: Single line diagram of Example 2.3.
Example 2.4 A simple power system is shown in Figure bellow. Redraw this system where the per unit
reactance of the components is represented on a common 5000 VA base and common system base voltage of
250 V.
Example 2.5 The single line diagram of a threephase power system is shown in Figure below.
Select a common base of 100 MVA and 13.8 kV
on the generator side. Draw the per unit impedance
diagram with new values per unit reactance’s.
Figure: Single line diagram of power system of
Example 2.5.
Reactance diagram