A 115 kV three-phase transposed transmission line is composed of 2-ACSR 336,400 cmil, 30/7 Oriole conductors per phase with horizontal configuration: \(D_{12}\) = 7 ft, \(D_{23}\) = 7 ft and \(D_{13}\) = 14 ft. The line spacing is measured from the center of the bundled conductors. The distance between the conductors of the bundle is 6 inches. The conductors have a diameter of 0.741 inch and GMR of 0.02255 ft. Find the capacitance per phase for 20 km of the line in μF.
A0.13
B0.27189
C0.2889
D0.2609
#22📜 EE Pre-Board March 2013📘 PowerhouseMedium
A 15MW, 132 kV, 80%power factor three phase load is to be served by a transmission line having conductors whose resistance is 0.5 ohm/km. If the losses on the line shall not exceed 4.5%, how long must this line be?
A66 km
B68 km
C70 km
D75 km
#23📜 EE Pre-Board March 2013📘 PowerhouseHard
It is desired to deliver 4,000 kW, three-phase at a distance of 25 miles. The load voltage being 33 kV, 60 Hz and the power factor of the load being 85% lagging. The reactance of the line per phase is 0.692 ohm per mile. The line loss is 10% of the power delivered. What is the voltage regulation of the line?
A11.2%
B12.3%
C13.2%
D14.8%
#24📜 EE Pre-Board March 2013📘 PowerhouseHard
A three-phase, 60 Hz, transmission line has its conductors arranged in a triangular configuration so that the two distances between conductors are 7.62 m and the third is 12.8 m. The conductors are Dove with GMR of 0.0314 ft. If the line is 60km long, what is the inductive reactance of the line?
A38.73 Ω
B37.18 Ω
C30.98 Ω
D33.57 Ω
#25📜 EE Pre-Board March 2013📘 PowerhouseEasy
What is the equivalent of the constant C in the ABCD constants for the nominal-T circuit of a transmission line for which R = 10 Ω, \(X_L\) = 20 Ω and Y = 400 μS for each phase?
A\(0.996\angle 0.115^\circ\)
B\(22.25\angle 63.45^\circ\)
C10 + j20
D\(4 \times 10^{-4}\angle 90^\circ\)
#26📜 EE Pre-Board March 2013📘 PowerhouseMedium
A certain station in Luzon has 36 kV, 3-phase, is to supply 12 MW load at 30 kV and 0.8 p.f. lagging over a 3-phase transmission line. Find the resistance of the line if the length of the transmission line is 4,000 meters and the efficiency is 90%.
A6.31 Ω
B3.56 Ω
C4.45 Ω
D5.33 Ω
#27📜 EE Pre-Board August 2013📘 PowerhouseHard
An unconventional conductor consists of three strands arranged vertically. Find the GMR in terms of the radius r of an individual strand.
A1.564 r
B1.764 r
C1.704 r
D1.89 r
#28📜 EE Pre-Board August 2013📘 PowerhouseEasy
A string insulator has 4 units. The voltage across the bottom most unit is 30% of the total voltage. What is the string efficiency?
A30%
B60%
C75%
D83.33%
#29📜 EE Pre-Board August 2013📘 PowerhouseMedium
A transmission line has a total series impedance of 40 + j125 ohms and a total shunt admittance of \(10^{-3}\) mho. Determine the constant D of the line.
Aj0.001
B0.9376 + j0.0196
C1 + j0.0656
D0.001 + j0.0656
#30📜 EE Pre-Board August 2013📘 PowerhouseMedium
The capacitance between any two conductors of a three-phase, three-conductor cable is 2 μF. The cable operates at 11 kV line voltage and 50 Hz. What is the charging current through the cable capacitance?
A7.98 A
B3.99 A
C6.91 A
D13.82 A
#31📜 EE Pre-Board August 2013📘 PowerhouseHard
A 40 mile, 60 cycle single-phase line consists of two 000 conductors spaced 5 ft apart. Determine the charging current if the voltage between wires is 33 kV. The diameter of 000 conductors is 410 mils.
A3.92 A
B2.92 A
C1.92 A
D4.92 A
#32📜 EE Pre-Board August 2013📘 PowerhouseHard
A 170-mile, 230-kV, 60-HZ, three-phase single-circuit transmission line uses, a triangular arrangement with 20 ft. 20 ft, and 36 ft spacing respectively. If the line conductors have a GMR of 0.0217 ft, determine the capacitive susceptance to neutral per mile.
A\(4.81 \times 10^{-6}\) mho per mile
B\(12.74 \times 10^{-6}\) mho per mile
C\(7.92 \times 10^{-5}\) mho per mile
D\(2.47 \times 10^{-6}\) mho per mile
#33📜 EE Pre-Board August 2013📘 PowerhouseHard
A short 3-phase, 3-wire transmission line has an impedance of 3 + j4 ohms per wire. At the receiving end are connected a 3-phase inductive load drawing 3,500 kW at 0.8 power factor and line to line voltage of 13,200-volt and a capacitor bank drawing 150 amperes line current. Calculate the voltage at the sending end.
A13,808 V
B13,718 V
C13,758 V
D13,658 V
#34📜 EE Pre-Board March 2014📘 PowerhouseMedium
A single-circuit three-phase line operated at 60 Hz is arranged in a triangular configuration with distances of 20 ft., 20ft. and 38 ft. between conductors, the conductors are ACSR Drake with GMR of 0.0373 ft. Find the inductive reactance per mile per phase.
A0.478 Ω
B0.578 Ω
C0.788 Ω
D0.678 Ω
#35📜 EE Pre-Board March 2014📘 PowerhouseHard
The terminal voltage of a Y-connected load consisting of three equal impedances of \(20\angle 30^\circ\ \Omega\) is 4.4 kV line to line. The impedance in each of the three lines connecting the load to a bus at a substation is \(Z_L = 1.4\angle 75^\circ\ \Omega\). Find the line to line voltage at the substation bus.
A4.52 kV
B4.62 kV
C4.48 kV
D4.58
#36📜 EE Pre-Board March 2014📘 PowerhouseHard
A 170-mile, 230 kV, 60 Hz, three-phase single-circuit transmission line uses a triangular arrangement with 20 ft, 20 ft and 36 ft spacing, respectively. If the line conductors have a GMR of 0.0217 ft, determine the capacitive susceptance to neutral per mile.
A\(4.81 \times 10^{-6}\) mho per mile
B\(12.74 \times 10^{-6}\) mho per mile
C\(7.92 \times 10^{-6}\) mho per mile
D\(2.47 \times 10^{-6}\) mho per mile
#37📜 EE Pre-Board March 2014📘 PowerhouseMedium
A single phase transmission line has a total impedance of \(5\angle 60^\circ\) ohms and supplies a total load of 120 A at 3.3 kV and 0.8 power factor lagging. Calculate the sending end voltage.
A3.93 kV
B3.62 kV
C3.54 kV
D3.86 kV
#38📜 EE Pre-Board March 2014📘 PowerhouseHard
A short 230 kV transmission line has an impedance of \(5\angle 78^\circ\) ohms. The sending end power is 100 MW at 230 kV and 85% power factor. What is the voltage at the other end?
A225.4 kV
B226.3 kV
C223.2 kV
D228.2 kV
#39📜 EE Pre-Board August 2014📘 PowerhouseMedium
A 3- phase overhead transmission line is being supported by three disc insulators. The potentials across top unit and middle unit are 8 KV and 11 KV, respectively. Calculate the ratio of capacitance between pin and earth to the self- capacitance between pin and earth to the self-capacitance of each unit.
A0.475
B0.775
C0.375
D0.275
#40📜 EE Pre-Board August 2014📘 PowerhouseHard
A short 3Φ line with an impedance of 6 + j8 ohms per line has sending and receiving end line voltages of 120 and 110 kV, respectively, for some receiving end load at a p.f. of 0.9 lagging. The active power at the receiving end is nearest to
