Power System Analysis

A transmission line has (2 + j4)Ω impedance, 100 MVA, and the base voltage is 10 kV. Find the per unit impedance value of transmission line

• (2 + j4 ) pu

• (1 + j2 ) pu

• (4 + j8 ) pu

• (0.5 + j1 ) pu

In a Delta-connected source feeding a Y-connected load,

• Each phase voltage equals the difference of the corresponding load voltages

• Each phase voltage equals the corresponding load voltage

• Each phase voltage is one-third the corresponding load voltage

• Each phase voltage is 60° out of phase with the corresponding load voltage

A generator has a rating of 10 MVA, 5 kV has a reactance of 0.02 pu. Find the reactance at a new base value of 50 MVA, 10 kV?

• 0.02

• 0.025

• 0.05

• 0.25

The Problem of stability occurs in

• None of these

• D.C lines only

• A.C lines only

• both D.C and A.C Lines

In a three-phase system, the voltages are separated by

• 45°

• 90°

• 120°

• 180°

In a certain three-wire Y-connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages are

• 2,000 V

• 6,000 V

• 666 V

• 3,464 V

Specified quantities of slack bus are

• P and Q

• V and δ

• P and δ

• P and V

The value of the zero-sequence impedance is

• Z 0 = 0

• Z 0 = Z + 3 Zn

• Z 0 = Z + 2 Zn

• Z 0 = Z

The phasor operator which is used to depict the unbalanced phase voltages into three phase quantities, provides a rotation of

• 120o counter clockwise

• 120o clockwise

• 90o counter clockwise

• 90o clockwise

The line current IR flowing into balanced delta connected load is - j5 - 3 A. If the phase sequence is RYB the phase current IYB is

• 5.

• 10.

• 20.

• 55.1