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The underground transmission and distribution of power is better than the corresponding overhead transmission and distribution in respect of _________
d Explanation: All the points are advantageous with respect to overhead transmission line in an underground power transmission system
d
See lessExplanation: All the points are advantageous with respect to overhead transmission line
in an underground power transmission system
A 240 kV 2μs rectangular pulse surge on a transmission line has surge impedance of 350 ohms. It approaches a generating station with capacitance of 3000 pF. The transmitted voltage will be ____________
a Explanation: Vt = 2Vi(1-e(-t/Zc)) = 2*240*1000(1-e-2*10-6 /3*350*10-9)
a
See lessExplanation: Vt = 2Vi(1-e(-t/Zc)) = 2*240*1000(1-e-2*10-6
/3*350*10-9)
A rectangular voltage wave is impressed on a long overhead line, with the far end of the line being open circuited. After reaching line end, the current is _______
b Explanation: For open circuited end, ρ(v) = 1; ρ(i) = -1
b
See lessExplanation: For open circuited end, ρ(v) = 1; ρ(i) = -1
The larger power can be transmitted over a line with fixed voltage profile when ____
d Explanation: Compensators allow the flow of a large power through the TL by feeding positive VAR into the system
d
See lessExplanation: Compensators allow the flow of a large power through the TL by feeding
positive VAR into the system
With 100% series compensation of the transmission lines, which of the following effects are not observed? (i) Low transient voltage (ii) High transient current (iii) The current is series resonant at power frequency
b Explanation: 100% compensation of the line results in high transient current at power frequency.
b
See lessExplanation: 100% compensation of the line results in high transient current at power
frequency.
Which of the parameters of a long transmission line and medium transmission lines are same?
a Explanation: A and D parameters of LTL and MTL are almost same.
a
See lessExplanation: A and D parameters of LTL and MTL are almost same.
For the lines more than 250 km, the parameters of a line are considered not ______ but ____
a Explanation: For long transmission lines, the parameters are considered uniformly distributed
a
See lessExplanation: For long transmission lines, the parameters are considered uniformly
distributed
For a medium transmission line system if the sending end line voltage is 143 kV with the line impedance as 101.24∠74° Ω and shunt admittance of 7.38*10-4∠90° Ω-1 delivering 25 MVA at 0.8 power factor lagging in nature to the load at 132 kV. The voltage regulation is ___________
a
a
See lessFor a medium transmission line system if the sending end line voltage is 143 kV with the line impedance as 101.24∠74° Ω and shunt admittance of 7.38*10-4∠90° Ω-1.Then the no load line voltage at the receiving end would be
a
a
See lessA single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the receiving end current at this operation mode will be ____________
a Explanation: VR = (11.68-10)*100/10 VR = 16.8 % Half the VR = 16.8/2 % Half the VR = 8.4% (10.84-10)*1000 = |I|*(RcosФr + XsinФr) …(1) I = 5000/(cosФr*10) …(2) Solving above equation Фr = 18.04°, lagging I = 526 A
a
See lessExplanation: VR = (11.68-10)*100/10
VR = 16.8 %
Half the VR = 16.8/2 %
Half the VR = 8.4%
(10.84-10)*1000 = |I|*(RcosФr + XsinФr) …(1)
I = 5000/(cosФr*10) …(2)
Solving above equation
Фr = 18.04°, lagging
I = 526 A