Electrical Power & Machines Eng. Program
Electrical Testing (EPE 323)
Mid-Term Exam
Model A
Total Marks: 25
Date: Monday 18/04/2022
Time allowed: 50 Minutes
Second Semester 2021/2022
Number of Questions: 25
Number of Pages: 2
Answer the Following Questions:
(1) 
(2)
(3)
(4)
(5)
(6) 
(7) 
(8) 
(9) 
(10) 
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
1
Which of the following is not the feature of a modern control system?
a
Accuracy
2
The input of a controller is:
a
Sensed signal
3
A first order dynamic system with a proportional controller exhibits an offset to a unit step input. The offset can be eliminated by:
a
high the proportional gain
4
Derivative output compensation:
a
Reduction in overshoot value
5
In short overhead transmission line (up to 80 km), we may neglect:
a
Series resistance
6
The transfer function of a P-D controller is:
a
Kp+KdS
7
The output of the feedback control system must be a function of
a
Output and feedback signal
8
A control system is generally met with the time response specifications:
a
Damping factor
9
The transfer function of the system is G(s) =100/s2+2s+100. For a unit step input to the system the approximate settling time for 2%
criterion is
a
100 sec
10
Find the initial and final values of the following function: C(s) = 12(s+1)/(s(s+3) (s+2) ^2)
a
1, ∞
11
The damping ratio and peak overshoot are measures of:
a
Relative stability
12
In a control system proportional error compensation .........steady state error
a
Increases
13
235 km line is considered as:
b
Quick response
c
No oscillation
d
Correct power level
b
Reference signal
c
Desired signal
d
Both (b,c)
b
b
b
b
b
b
b
b
b
b
Adding derivative mode
c
Adding integral mode
d
low the proportional gain
Reduction in steady state
error
c
Increase in settling time
d
Increase in damping constant
c
Shunt capacitance
d
All the above
c
Kd+Ki/S
d
Kp+Ki/S
c
Reference input
d
Reference output
Steady state accuracy
d
All the mentioned
Series inductance
Kp+Kd/S
Input and feedback signal
Setting time
4 sec
0, ∞
Speed of response
Minimizes
c
c
1 sec
d
0.01 sec
c
∞,1
d
0,1
c
Steady state error
d
Absolute stability
d
Any of the above
c
Does not have any effect on
a
a long line
b
14
It is the time taken by the response to change from 0 to 50% of its final value.
a
Peak time
15
Effect of feedback on sensitivity is minimum in:
a
Open loop control system
16
What is the algebraic sum of the reference input and feedback?
a
Error Signal
17
As unity feedback system has a forward path transfer function G(s) = K/s(s+8) where K is the gain of the system. The value of K, for
making this system critically damped should be
a
4
18
For the system, C(s)/R(s) = 16/(s2+16s+16). The nature of the response will be
a
Overdamped
19
A larger phase margin …... the overshoot and ….... The system stability.
a
Increases, Improves
20
For proportional control the steady state error (offset) tends to Zero when Kp is
a
Infinity
21
Which of the following are the constants of the transmission lines?
a
Resistance
22
………… controller is used for obtaining small rise time, small overshoot and has no change in SSE
a
Proportional (P)
23
A 3-phase T.L has resistance of 1.5 ohm and reactance of 4 ohm per phase. The efficiency of the line when supplying the load of 4 MW
at 0.8 lagging power factor at 22kV is
a
85%
24
In MATLAB pidtuner. By default, the algorithm designs for a …. Degree phase margin.
a
0
25
You can access the tuning algorithm directly through a nice graphical user interface (GUI) using
a
pidtune
b
b
b
b
b
b
b
b
b
b
b
b
a medium line
Rise time
Closed loop control system
Error Detector
8
Underdamped
Decreases, Improves
Zero
Inductance
Integral (I)
94%
30
PIDTuner
c
a short line
d
any of the above
c
Delay time
d
Settling time
c
None of the mentioned
d
Both the mentioned
c
Controlled system
d
Controlled output
c
c
c
16
Critically damped
Decreases, Worsen
d
32
d
None of the mentioned
d
Increases, Worsen
c
One
d
0.5
c
Capacitance
d
All the above
d
PID
c
c
c
c
Derivative (D)
99%
60
pidTuner
d
90%
d
90
d
None of the above
Electrical Power & Machines Eng. Program
Electrical Testing (EPE 323)
Mid-Term Exam
Model B
Total Marks: 25
Date: Monday 18/04/2022
Time allowed: 50 Minutes
Second Semester 2021/2022
Number of Questions: 25
Number of Pages: 2
Answer the Following Questions:
(1) 
(2)
(3)
(4)
(5)
(6) 
(7) 
(8) 
(9) 
(10) 
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
1
………… controller is used for obtaining small rise time, small overshoot and has no change in SSE
a
Proportional (P)
2
Which of the following are the constants of the transmission lines?
a
Resistance
3
As unity feedback system has a forward path transfer function G(s) = K/s(s+8) where K is the gain of the system. The value of K, for
making this system critically damped should be
a
4
4
For the system, C(s)/R(s) = 16/(s2+16s+16). The nature of the response will be
a
Overdamped
5
You can access the tuning algorithm directly through a nice graphical user interface (GUI) using
a
pidtune
6
What is the algebraic sum of the reference input and feedback?
a
Error Signal
7
A larger phase margin …... the overshoot and ….... The system stability.
a
Increases, Improves
8
A 3-phase T.L has resistance of 1.5 ohm and reactance of 4 ohm per phase. The efficiency of the line when supplying the load of 4 MW
at 0.8 lagging power factor at 22kV is
a
94%
9
For proportional control the steady state error (offset) tends to Zero when Kp is
a
Infinity
10
The transfer function of the system is G(s) =100/(s2+2s+100). For a unit step input to the system the approximate settling time for 2%
criterion is
a
100 sec
11
Derivative output compensation:
a
Reduction in overshoot value
12
A control system is generally met with the time response specifications:
a
Damping factor
13
The damping ratio and peak overshoot are measures of:
b
b
b
b
b
b
b
b
b
b
b
b
Integral (I)
Inductance
8
Underdamped
PIDTuner
Error Detector
Decreases, Improves
99%
Zero
c
Derivative (D)
d
PID
c
Capacitance
d
All the above
c
c
16
Critically damped
d
32
d
None of the mentioned
c
pidTuner
d
None of the above
c
Controlled system
d
Controlled output
d
Increases, Worsen
c
c
c
Decreases, Worsen
90%
One
d
85%
d
0.5
4 sec
c
1 sec
d
0.01 sec
Reduction in steady state
error
c
Increase in settling time
d
Increase in damping constant
Steady state accuracy
d
All the mentioned
Setting time
c
a
Relative stability
b
14
In MATLAB pidtuner. By default, the algorithm designs for a …. Degree phase margin.
a
0
15
Find the initial and final values of the following function: C(s) = 12(s+1)/(s(s+3) (s+2) ^2)
a
1, ∞
16
In a control system proportional error compensation .........steady state error
a
Increases
17
The output of the feedback control system must be a function of
a
Output and feedback signal
18
In short overhead transmission line (up to 80 km), we may neglect:
a
Series resistance
19
The transfer function of a P-D controller is:
a
Kp+KdS
20
Effect of feedback on sensitivity is minimum in:
a
Open loop control system
21
Which of the following is not the feature of a modern control system?
a
Accuracy
22
235 km line is considered as:
a
a long line
23
It is the time taken by the response to change from 0 to 50% of its final value.
a
Peak time
24
The input of a controller is:
a
Sensed signal
25
A first order dynamic system with a proportional controller exhibits an offset to a unit step input. The offset can be eliminated by:
a
high the proportional gain
b
b
b
b
b
b
b
Speed of response
30
0, ∞
Minimizes
Input and feedback signal
Series inductance
Kp+Kd/S
Closed loop control system
c
c
c
Steady state error
60
∞,1
d
Absolute stability
d
90
d
0,1
c
Does not have any effect on
d
Any of the above
c
Reference input
d
Reference output
c
Shunt capacitance
d
All the above
c
Kd+Ki/S
d
Kp+Ki/S
c
None of the mentioned
d
Both the mentioned
b
Quick response
c
No oscillation
d
Correct power level
b
a medium line
c
a short line
d
any of the above
b
Rise time
c
Delay time
d
Settling time
b
Reference signal
c
Desired signal
d
Both (b,c)
b
Adding derivative mode
c
Adding integral mode
d
low the proportional gain