MSc Competitive Exam
Q.1
When a line-to-ground fault occurs, the current in a faulted phase is 100 A. calculate
the zero sequence current.
Q.2 The following sequence currents were recorded in a power system under a fault
condition Ipositive=j1.753 pu, Inegative=-j0.6 pu, Izero=-j1.153pu. Prove the fault is line
to line ground.
tan 𝑥
Q.3 Find the following limit 𝑙𝑖𝑚 𝑥→0 𝑥
Q.4 A negative feedback closed loop system is supplied an input of 5 volt. The
system has a forward gain (1) and feedback gain (1). What is the output voltage?
Q.5 For flat voltage profile system, find the voltage regulation
Q.6 A transmission line has a reactance of 1 Pu is operating at Vs = Vr = 1 Pu. The
generator is connected at source end which is delivering 0.5 Pu of active power. Find
the load angle?
Q.7 In a type A chopper, source voltage is (100V dc). On-period is (100 𝜇𝑠𝑒𝑐), off-
period is (150 𝜇𝑠𝑒𝑐)and load RLE consist of R =2Ω, L =5mH, and E =10V. For
continues conduction what are the average output voltage and current?
Q.8 In a 3-phase half wave rectifier, if per phase input voltage is 200V, Determine the
average output voltage?
Q.9 A 4-pole, long-shunt lap-wound generator supplies 25 kW at a terminal voltage of 500 V.
The armature resistance is (0.03 ohm), series field resistance is (0.04 ohm) and shunt field
resistance is (200 ohm). The brush drop may be taken as (1.0 V). Determine the e.m.f.
generated. Calculate also the No. of conductors if the speed is (1200 r.p.m.) and flux per pole
is (0.02 weber). Neglect armature reaction.
Q.10 A 4-pole, 3-phase induction motor operates from a supply whose frequency is 50Hz.
Calculate:
(i) the speed at which the magnetic field of the stator is rotating?
(ii) the speed of the rotor when the slip is 0.04?
,(iii) the frequency of the rotor currents when the slip is 0.03?
(iv) the frequency of the rotor currents at standstill?
N.B. ANSWER ALL QUESTIONS
, Electrical Engineering Electrical Power
Technical College Engineering Techniques
Department of Electrical Power Time: 90 minutes
Engineering Techniques Jun 2019
MSc Competitive Exam
1. Transients in electric circuits normally disappears within a time equal to
A. 4 x time constant
B. 8 x time constant
C. Time constant
2. Which one of the following is correct?
A. Xd''= Xd' = Xd
B. Xd''< Xd' < Xd
C. Xd''> Xd' > Xd
3. Fault level means
A. Voltage at the point of fault
B. Fault current
C. Fault MVA
4. Fault calculations using computer are usually done by
A. Ybus method
B. Zbus method
C. Any of the above
5. the most frequently occurring fault in the power system is
A. Single line to ground fault
B. Double line to ground fault
C. Symmetrical fault ( 3- ϕ fault)
𝑑
1. (cot 𝑥) equals:
𝑑𝑥
A. csc2x
B. -sec2x
C. sec2 (-x)
D. –csc2x
2. 𝑙𝑛(𝑥 + 𝑖𝑦) =
A. 𝑐𝑜𝑠(𝑥) 𝑐𝑜𝑠ℎ(𝑦) − 𝑖 𝑠𝑖𝑛(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
B. 𝑠𝑖𝑛(𝑥) 𝑐𝑜𝑠ℎ(𝑦) + 𝑖 𝑐𝑜𝑠(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
C. 𝑐𝑜𝑠(𝑥) 𝑐𝑜𝑠ℎ(𝑦) + 𝑖 𝑠𝑖𝑛(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
D. 𝑠𝑖𝑛(𝑥) 𝑐𝑜𝑠ℎ(𝑦) − 𝑖 𝑐𝑜𝑠(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
3- cos(-ϴ) equals:
A. -cos ϴ
B. cos ϴ
C. -sin ϴ
D. 0
Q.1
When a line-to-ground fault occurs, the current in a faulted phase is 100 A. calculate
the zero sequence current.
Q.2 The following sequence currents were recorded in a power system under a fault
condition Ipositive=j1.753 pu, Inegative=-j0.6 pu, Izero=-j1.153pu. Prove the fault is line
to line ground.
tan 𝑥
Q.3 Find the following limit 𝑙𝑖𝑚 𝑥→0 𝑥
Q.4 A negative feedback closed loop system is supplied an input of 5 volt. The
system has a forward gain (1) and feedback gain (1). What is the output voltage?
Q.5 For flat voltage profile system, find the voltage regulation
Q.6 A transmission line has a reactance of 1 Pu is operating at Vs = Vr = 1 Pu. The
generator is connected at source end which is delivering 0.5 Pu of active power. Find
the load angle?
Q.7 In a type A chopper, source voltage is (100V dc). On-period is (100 𝜇𝑠𝑒𝑐), off-
period is (150 𝜇𝑠𝑒𝑐)and load RLE consist of R =2Ω, L =5mH, and E =10V. For
continues conduction what are the average output voltage and current?
Q.8 In a 3-phase half wave rectifier, if per phase input voltage is 200V, Determine the
average output voltage?
Q.9 A 4-pole, long-shunt lap-wound generator supplies 25 kW at a terminal voltage of 500 V.
The armature resistance is (0.03 ohm), series field resistance is (0.04 ohm) and shunt field
resistance is (200 ohm). The brush drop may be taken as (1.0 V). Determine the e.m.f.
generated. Calculate also the No. of conductors if the speed is (1200 r.p.m.) and flux per pole
is (0.02 weber). Neglect armature reaction.
Q.10 A 4-pole, 3-phase induction motor operates from a supply whose frequency is 50Hz.
Calculate:
(i) the speed at which the magnetic field of the stator is rotating?
(ii) the speed of the rotor when the slip is 0.04?
,(iii) the frequency of the rotor currents when the slip is 0.03?
(iv) the frequency of the rotor currents at standstill?
N.B. ANSWER ALL QUESTIONS
, Electrical Engineering Electrical Power
Technical College Engineering Techniques
Department of Electrical Power Time: 90 minutes
Engineering Techniques Jun 2019
MSc Competitive Exam
1. Transients in electric circuits normally disappears within a time equal to
A. 4 x time constant
B. 8 x time constant
C. Time constant
2. Which one of the following is correct?
A. Xd''= Xd' = Xd
B. Xd''< Xd' < Xd
C. Xd''> Xd' > Xd
3. Fault level means
A. Voltage at the point of fault
B. Fault current
C. Fault MVA
4. Fault calculations using computer are usually done by
A. Ybus method
B. Zbus method
C. Any of the above
5. the most frequently occurring fault in the power system is
A. Single line to ground fault
B. Double line to ground fault
C. Symmetrical fault ( 3- ϕ fault)
𝑑
1. (cot 𝑥) equals:
𝑑𝑥
A. csc2x
B. -sec2x
C. sec2 (-x)
D. –csc2x
2. 𝑙𝑛(𝑥 + 𝑖𝑦) =
A. 𝑐𝑜𝑠(𝑥) 𝑐𝑜𝑠ℎ(𝑦) − 𝑖 𝑠𝑖𝑛(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
B. 𝑠𝑖𝑛(𝑥) 𝑐𝑜𝑠ℎ(𝑦) + 𝑖 𝑐𝑜𝑠(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
C. 𝑐𝑜𝑠(𝑥) 𝑐𝑜𝑠ℎ(𝑦) + 𝑖 𝑠𝑖𝑛(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
D. 𝑠𝑖𝑛(𝑥) 𝑐𝑜𝑠ℎ(𝑦) − 𝑖 𝑐𝑜𝑠(𝑥) 𝑠𝑖𝑛ℎ(𝑦)
3- cos(-ϴ) equals:
A. -cos ϴ
B. cos ϴ
C. -sin ϴ
D. 0
