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This set of Switch Gear and Protection Multiple Choice Questions & Answers (MCQs) focuses on Switch Gear And Protection Set 5
Q1 | Oil switches are employed for
- low currents circuits
- low voltages circuits
- high voltages and large currents circuits
- all circuits
Q2 | A switchgear is device used for
- interrupting an electrical circuit
- switching an electrical circuit 111.
- switching and controlling an electrical circuit
- switching, controlling and protecting the electrical circuit and equipment
Q3 | The fuse wire, in D.C. circuits, is inserted in
- negative circuit only
- positive circuit only
- both (a) and (b)
- either (a) or (b)
Q4 | By which of the following methods major portion of the heatgenerated in a H.R.C. fuse is dissipated ?
- Radiation
- Convection
- Conduction
- All of the above
Q5 | A short-circuit is identified by
- no current flow
- heavy current flow
- voltage drop
- voltage rise
Q6 | The information to the circuit breaker under fault conditions isprovided by
- relay
- rewirable fuse
- H.R.C. only
- all of the above
Q7 | To limit short-circuit current in a power system are used.
- earth wires
- isolators
- H.R.C. fuses
- reactors
Q8 | A balanced 3-phase system consists of
- zero sequence currents only
- positive sequence currents only
- negative and zero sequence currents
- zero, negative and positive sequence currents
Q9 | In a single bus-bar system there will be complete shut down when
- fault occurs on the bus itself
- fault occurs on neutral line
- two or more faults occur simultaneously
- fault occurs with respect to earthing
Q10 | Which device is used for protection of equipment from from damagecaused by overload or short circuit?
- CVT
- Circuit Breaker
- Current Transformer
- Lighting Arrester
Q11 | Isolator in substation is open under ------------- condition?
- No load
- Short Circuit
- Full Load
- Any of the above
Q12 | Earthling switch is used for
- measuring of safety voltage
- protection of equipment from ground faults
- discharging residual energies
- all of the above
Q13 | If the time of operating of a relay for unity TMS is 10secs., the time ofoperation for 0.5 TMS will be
- 20 secs.
- 5 secs.
- 10 secs.
- None of the above
Q14 | A fault is more severe from the view point of RRRV if is a
- Short line fault.
- Medium length line fault.
- Long line fault.
- None of these.
Q15 | A reactance relay is
- Voltage restrained directional relay.
- Directional restrained over-current relay.
- Voltage restrained over-current relay.
- None of the above.
Q16 | For measuring positive, negative and zero sequence voltages in asystem, the reference is taken as
- Neutral of the system only.
- Ground only.
- For zero sequence neutral and for positive and negative the ground.
- None of the above.
Q17 | Positive, negative and zero sequence impedances of a solidly grounded system under steady state condition always follow the relations
- Z4>Z2>Z0
- Z2>Z4>Z0
- Z0>Z4>Z2
- None of the above
Q18 | Phase comparators in case of static relays and electro-mechanical relaysnormally are
- Sine and cosine comparators respectively
- Cosine and sine comparators respectively.
- Both are cosine comparators.
- Both are sing comparators.
Q19 | For reducing tower footing resistance it is better to use
- Chemical and ground rods only.
- Chemical and counterpoise only.
- Ground rod and counterpoise only.
- Chemical, ground rods and counterpoise.
Q20 | Rate of rise of restriking voltage depends
- Type of circuit breaker.
- Inductance of the system only.
- Capacitance of the system only.
- Inductance and capacitance of the system
Q21 | What is the purpose of back up protection?
- To increase the speed
- To increase the reach
- To leave no blind spot
- To guard against failure of primary
Q22 | What is the actuating quantity for the relays?
- Magnitude
- Frequency
- Phase angle
- All of these
Q23 | Protective relays can be designed to respond to
- Light intensity, impedance
- Temperature, resistance, reactance
- Voltage and current
- All of these
Q24 | On what factor does the operating speed of the relay depend upon?
- Rate of flux built up
- Armature core air gap
- spring tension
- All of these
Q25 | What does the third part consist of?
- Primary winding of a current CT which is connected in series with the line to be protected.
- Secondary of the CT and the operating coil.
- Tripping circuit.
- All of these.