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1.0.0
MCQ
2341. Fault level means-
fault current
fault MVA
voltage at the point of fault
none
2342. In aluminium conductors, steel core is provided to-
compensate for skin effect
neutralise proximity effect
reduce line inductance
increases the tensile strength
ব্যাখ্যা: Aluminium is light in weight and is having good conductivity. But it is having very low tensile strengst To make it suitable to be used as a conductor for the transmission line, we need to increase its tensile strength. To increase the tensile strength steel is used as a core of conductor.
2343. A fuse is a--
protective device
current limiting device
current controling device
none of the above
ব্যাখ্যাঃ in electronic and electrical engineering, a fuse is an electrical safety or protective device, that operates provide overcurrent protection of an electrical circuit
2344. Differential relay is used for protection of--
Transmission line
Equipment having windings
Distribution line
None
2345. Breaking current is a value.
RMS
Maximum
Average
Any of the above
2346. IDMT relays are used to protect the power transformers against-
External short-circuit
Overloads
Internal short-circuits
Both (a) and (b)
2347. In sheet metal blanking, shear is provided on punches and dies so that--
press load is reduced
good cut edge in obtained
warping of sheet is minimized
cut blanks are straight
2348. The most severe fault on the power system is-
there phase short circuit
line to line fault
double line to ground fault
single line to ground fault
2349. The relay operation coil is supplied through-
fuse
power transformer
current transformer
none
ব্যাখ্যা: The relay operating coil is supplied through current treansformer. Current transformer is used to measure the current as the indication for relay.
2350. In SF6 circuit breakers, the SF, gas-
has insulating properties
is non-inflammable
is non-poisonous
all of the above
2351. SF6 gas is used as it has-
High-boiling point
Electronegativity
Good conductivity
None
2352. Most faults occurring in the field are in-
CTs and PTS
switchgears
overhead lines
cables
ব্যাখ্যা: Most faults occuring overhead lines. Because in raining day, there is more probability to occur fault. Leakage current and short circuit current frequently occured an raining day
2353. Inverse time current relays are used for the protection of-
Feeders
Transformers
Alternators
Both A and B
ব্যাখ্যা: Inverse time current relays, operating time is inversely changed with current So, hich current will operate over current relay faster than lower ones. It is used feeders and transformers
2354. A thermal protection switch can protect against-
Short-circuit
Overload
Temperature
Over voltage
2355. বাংলাদেশে কয়টি ন্যাশনাল গ্রিড লাইন আছে?
1 টি
3টি
2টি
4টি
2356. The operating speed of a relay depends upon the-
Rate of flux built up
Armature core air gap
Spring tension
All of these
2357. A circuit breaker is essentially-
an automatic switch
a manual switch
a high-lightning arrester
none of the above
ব্যাখ্যা: A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit.
2358. An isolator is designed to open a circuit--
full load
normal condition
no load
all of the above
ব্যাখ্যা : An isolator is designed to open a circuit under no load Its main purpose is to isolate one portion of the circsil from the other and is not intended to be opened while current is flowing in the line
2359. Under normal operating conditions, the contacts of the circuit breaker remain-
closed
semiclosed
open
none of the above
ব্যাখ্যা: Under normal operating conditions, the contacts the circuit breaker remain closed. When any fault occart the contact is opened.
2360. 8A generator supplies 100 MVA at 0.5 power factor. What is in MW?
100
90
200
None