Electrical engineering Important Questions for HPCL | ISRO | GATE | BARC |ESE | UPPSC

Electrical engineering Important Questions for HPCL | ISRO | GATE | BARC |ESE | UPPSC

Q1. A synchronous generator connected to an infinite bus is overexcited. Consider the only reactive power, from the point of view of the system, the machine acts as
  • a) a capacitor
  • b) an inductor
  • C) a resistor
  • d) none of these

Q2. The voltage stress will be maximum in an underground cable at
  • a) The surface of the sheath
  • b) The surface of the conductor
  • c) The surface o the insulation.
  • d) The surface of the armour.

Q3. The dielectric strength of air at a barometric pressure of 76cm and 25
degree centigrade is
  • a) 30kv/ metre.
  • b) 21.1kv rms/ cm.
  • c) 21.1kv rms/ mm.
  • d) 110kv / metre.

Q4. The positive sequence current of a transmission line is
  • a) always zero
  • b) one-third of negative sequence current
  • c) three times the negative sequence current
  • d) equal to negative sequence current

Q5. For the fault at the terminals of a synchronous generator, the fault current is maximum for a
  • a) 3-phase fault
  • b) 3-phase to ground fault
  • c) Line-to-ground fault
  • d) Line-to-line fault

Q6. The earth transformer is used to
  • a) Avoid the harmonics in the transformers
  • b) Provide artificial neutral earthing where neutral point is not accessible
  • c)Improve stability of the system
  • d) Measure the voltage

Q7. For differential protection of power transformer (delta-delta) the current transformers will have
  • a) Delta-delta connection
  • b) Star-delta connection
  • c) Star-star connection
  • d) Delta-star connection

Q8. For the protection of a very long extra high voltage line, the protective relay used is
  • a) Over current with extremely inverse characteristics
  • b) Percentage differential relay
  • c) Reactance type distance relay
  • d) Mho type distance relay

Q9. Resistance switching is normally employed in
  • a) All breakers
  • b) Bulk oil breaker
  • c) Minimum oil breaker
  • d) Air-blast circuit breaker

Q10. Symmetrical breaking capacity of ACB is
  • a) Greater than asymmetrical breaking capacity
  • b) Less than asymmetrical breaking capacity
  • c) Equal to asymmetrical breaking capacity
  • d) not related to asymmetrical breaking capacity

Q11. By which material the fuse element is generally made
  • a) Copper
  • b) Nickel
  • c) Iron alloy
  • d) Silver

Q12. Grounding is generally done in transmission line at
  • a) The supply end
  • b) The receiving end
  • c) Middle of the line
  • d) Anywhere

Q13. What is the approximate value of the surge impedance loading of a 400kV, 3-phase 50Hz overhead single circuit transmission line
  • a) 230 MW
  • b) 400 MW
  • c) 1000 MW
  • d) 1600 MW

Q14. When two identical first order systems have been cascaded non-
interactively the unit step response of the system will be
  • a) Over damped
  • b) Under damped
  • c) Un-damped
  • d) Critically damped

Q15. Which of the following methods is most strong tool to determine the stability and the transient response of the system ?
  • a) Routh-Hurwitz criterion.
  • b) Bode plot.
  • c) Nyquist plot.
  • d) Root locus.

Q16. If the gain of a critically damped system is increased, it will become
  • a) Under damped system
  • b) Over damped system
  • c) Oscillatory system
  • d) Critically damped system

Q17. Phase margin of a system is used to specify
  • a) Relative stability
  • b) Absolute stability
  • c) Time response
  • d) Frequency response

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