Power System Analysis, Stability & Computer Technique Test Questions - Set 9

1)   What information does the swing curve provide?

a. Stability of the system.
b. Performance of the machine
c. The rotor performance
d. All of these
e. None of these
Answer  Explanation 

ANSWER: Stability of the system.

Explanation:
No explanation is available for this question!


2)   What are the main applications of the swing curves?

a. Designing the rotor field windings
b. Designing the protective devices
c. Used to limit the size of the machine
d. All of these
e. None of these
Answer  Explanation 

ANSWER: Designing the protective devices

Explanation:
No explanation is available for this question!


3)   What will be the inertia constant H, for a water wheel generator having a speed less than 200 rpm?

a. 2 - 4
b. 2 - 3
c. 1 - 2
d. 5 - 6
Answer  Explanation 

ANSWER: 2 - 3

Explanation:
No explanation is available for this question!


4)   What is power angle equation of synchronous machines?

a. An equation between electrical power generated to the angular displacement of the rotor
b. An equation between mechanical power generated to the angular displacement of the rotor
c. An equation between electrical power generated to the angular displacement of stator windings
d. An equation between mechanical power generated to the angular displacement of stator windings
Answer  Explanation 

ANSWER: An equation between electrical power generated to the angular displacement of the rotor

Explanation:
No explanation is available for this question!


5)   At what value of ‘δ’ the maximum power transfer takes place?

a. 45 °
b. 90 °
c. 120 °
d. 180 °
Answer  Explanation 

ANSWER: 90 °

Explanation:
No explanation is available for this question!


6)   What is the range of ‘δ’ for stable operation?

a. 0° < δ < 45°
b. 45° < δ < 90°
c. 0° < δ < 90°
d. 0° < δ < 120°
Answer  Explanation 

ANSWER: 0° < δ < 90°

Explanation:
No explanation is available for this question!


7)   Which among the following methods are used to improve steady state stability?

a. Reducing the reactance between the transmission and receiving points.
b. By using bundled conductors.
c. By increasing the excitation of generator or motor or both.
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!


8)   Why are the series capacitors used?

a. Improve the voltage
b. Reduce the fault level
c. Compensate for line inductive reactance and improve the stability of the power system.
d. Improves the power factor
Answer  Explanation 

ANSWER: Compensate for line inductive reactance and improve the stability of the power system.

Explanation:
No explanation is available for this question!


9)   Which stability information is obtained from the equal area criterion?

a. Absolute stability
b. Transient stability
c. Steady state stability
d. Both (b) and (c)
e. All of these
Answer  Explanation 

ANSWER: Absolute stability

Explanation:
No explanation is available for this question!


10)   For which among the following cases is the equal area criterion of stability used?

a. One machine and infinite bus bar
b. No load on bus bar
c. Many machines and infinite bus bar
d. All of these
e. None of these
Answer  Explanation 

ANSWER: One machine and infinite bus bar

Explanation:
No explanation is available for this question!


11)   What are the common assumptions made for the equal area criterion?

a. The transmission line and machine resistances are neglected.
b. Rotor speed of the machine is constant
c. Mechanical input remains constant.
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!


12)   Which among these cannot be determined from equal area criterion?

a. Critical clearing angle
b. Critical clearing time
c. Transient stability limit
d. Both (a) and (b)
e. All of these
Answer  Explanation 

ANSWER: Critical clearing time

Explanation:
No explanation is available for this question!


13)   Which among these is related to the critical clearing time of a fault in a power system?

a. Transient stability limit
b. Steady state stability limit
c. Frequency limit
d. All of these
e. None of these
Answer  Explanation 

ANSWER: Transient stability limit

Explanation:
No explanation is available for this question!


14)   With the use of high speed circuit breakers, which among the following stability is increased?

a. Steady state stability
b. Transient stability
c. Frequency stability
d. All of these
e. None of these
Answer  Explanation 

ANSWER: Transient stability

Explanation:
No explanation is available for this question!


15)   What will be the penalty factor for a unit, if the generating station is located very close to load centre?

a. Zero
b. Almost equal to unity
c. The penalty factor is negative
d. The value is very high
Answer  Explanation 

ANSWER: Almost equal to unity

Explanation:
No explanation is available for this question!


16)   How is the voltage and frequency controlled in automatic generation control?

a. By controlling the excitation
b. By controlling the turbine action
c. Turbine speed control for voltage and excitation control for frequency
d. Excitation control for voltage and turbine speed control for voltage.
Answer  Explanation 

ANSWER: Turbine speed control for voltage and excitation control for frequency

Explanation:
No explanation is available for this question!