01.A relay used on short transmission lines is
Reactance relay.
02.The main advantage of AC transmission system over DC transmission system is
less losses in transmission over long distances.
03.For the transmission of same power
AC line requires more copper than a DC line.
04.If the length of a cable is double , its capacitance
becomes double.
05.HT cables are generally used upto
11 kV.
06.In a transmission line insulators are used
suspension type.
07.Porcelain insulators are glazed because
to prevent absorption of gases and water vapour.
08.The function of circuit breaker is
to safe guard the circuit.
09.The type of insulator used for holding the HT overhead ocnductor on straight running of poles ?
Pin-type insulators.
10.A 11 kV underground cable is layed at a depth of
0.9 m.
11.Rewirable fuse is also known as
kit-kat fuse.
12.The fusing factor of HRC fuse is
1.1
13.Time delay relay is used in which relay type
thermal relay.
14.Single bare copper wire having voltage of
230 V.
15.The symmetrical components are used in the fault analysis because
the sequence networks do not have mutual couplings.
16.In a star-connected system without neutral grounding, zero-sequence currents are
zero.
17.A balanced 3-phase system consists of
positive-sequence currents only.
18.The positive sequence current of a transmission line is :
equal to negative current.
19.Negative-sequence reactance of a transformer is
equal to the positive-sequence reactance.
20.The material used in liquid fuses is
carbon tetra chloride.
21.HRC fuses have the advantage(s) of
high speed operation,
high rupturing capacity,
no ageing effect,
all of the above.
22.In HRC fuse the time between cut-off and final current zero is called the
arcing time.
23.For a circuit breaker 'break time' is
opening time + arc duration + resistor current duration.
24.When a fault occurs in a high voltage transmission line, first the
relay operates, then successively the isolator and the circuit breaker.
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