Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Switchgear and protection
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute
Q1. The most serious consequence of a major uncleared short-circuit fault could be
(a) Blowing of fuse
(c) heavy voltage drop
(d) none of these
Q2. Which of the following result in a symmetrical fault?
(a) single phase to earth
(b) phase to phase
(c) All the three phases to earth
(d) two phase to earth
Q3. Which portion of transmission system is more prone to faults?
(c) Overhead lines
(d) Underground cable
Q4. Which portion of power system is least prone to fault?
(c) Overhead lines
Q5. The most common type of fault is
(a) Single phase to ground
(b)Two phase to ground
(c) Phase to phase
(d) three phase to ground
Q6. The per unit value of a 4 Ω resistance at 100 MVA base and 10 kV base voltage is
(a) 6 pu
Q7. Series reactor are used to
(a) improve the transmission efficiency
(b) improve the power factor of the power system
(c) improve the voltage regulation
(d) Bring down the fault level within the capacity of the switch gear
Q8. Current limiting reactors may be
(a) air cored air cooled
(b) oil immersed magnetically shielded
(c) oil immersed non magnetically shielded
(d) any of above
Q9. Symmetrical components are used in power system for the analysis of
(a) balanced 3 phased faults
(b) unbalanced 3 phase faults
(c) normal power system under steady condition
(d) Stability of system under disturbance
Q10. The positive sequence current of a transmission line is:
(a) always zero
(b) 1/3 of negative sequence current
(c) equal to negative sequence current
(d) 3 times negative sequence current
Sol. Fire is the most serious consequence.
Sol. All the three phases to earth.
Sol. Overhead lines
S5. Ans. (a)
Sol. The most common type of fault is Single phase to ground.
S6. Ans. (c)
Sol. Rpu = R(ohm) ×MVA/(kV)^2
= 4 ×100/10^2 = 4 pu
S7. Ans. (d)
Sol. Bring down the fault level within the capacity of the switch gear.
S8. Ans. (d)
Sol. Any of above
Sol. unbalanced 3 phase faults
S10. Ans. (b)
Sol. 1/3 of negative sequence current