page 6 | Power Systems Multiple Choice Questions

Q61. In a 3 - phase system, the area of cross section of the neutral is generally

same as that of the outer conductors

Half of the outer conductors

Quarter of the outer conductors

Double of the outer conductors

Q62. Distribution transformers star-point (neutral) grounding is

solid grounding

resistance grounding

reactance grounding

insulated grounding

Q63. A single line diagram of a power system is shown in Fig. The elements of the \(Z_{bus}\) matrix are

\(Z_{bus}=\begin{bmatrix}j0.3&j0.2 \\j0.2&j0.3\end{bmatrix}\)

\(Z_{bus}=\begin{bmatrix}j0.3&j0.5 \\j0.5&j0.75\end{bmatrix}\)

\(Z_{bus}=\begin{bmatrix}j0.3&j0.2 \\j0.2&j0.5\end{bmatrix}\)

\(Z_{bus}=\begin{bmatrix}j0.3&j0.5 \\j0.5&j1.25\end{bmatrix}\)

Q64. The bus admittance matrix of a power system is not symmetrical when

shunt is connected

phase shifting transformer is connected

line is not modeled properly

can't say

Q65. A load bus with voltage support/control can be treated as ________

PQ bus

PV bus

Slack bus

None

Q66. For a load flow solution the quantities specified at the load bus are

P and Q

P and δ

Q and |V|

P and |V|

Q67. For stability reasons we operate the transmission line with power angle in the range

\(10^{\circ}- \: 25^{\circ}\)

\(30^{\circ}- \: 45^{\circ}\)

\(60^{\circ}- \: 75^{\circ}\)

\(65^{\circ}- \: 80^{\circ}\)

Q68. Steady state stability limit of unit occurs when power angle is …….degree.

30

45

90

0

Q69. If \(n_1\) is the refractive index of the core and \(n_2\) is the refractive index of the cladding, then the critical angle is given by

\(\sin^{-1}(\frac{n_1}{n_2})\)

\(\cos^{-1}(\frac{n_2}{n_1})\)

\(\cos^{-1}(\frac{n_1}{n_2})\)

\(\sin^{-1}(\frac{n_2}{n_1})\)

Q70. For the transient stability of a power system

\(\frac{d \delta}{dt}>0, \frac{dP}{d \delta}>0\)

\(\frac{d \delta}{dt}=0, \frac{dP}{d \delta}>0\)

\(\frac{d \delta}{dt}<0, \frac{dP}{d \delta}<0\)

\(\frac{d \delta}{dt}<0, \frac{dP}{d \delta}=0\)

MCQ

POWER SYSTEM