Transmission Lines

Porcelain insulators are protected against creepage of surge current by the use of _.

A uniform 2 wire dc distributor 500 meters long is loaded with 0.4 ampere/meter and is fed at one end. If the maximum permissible voltage drop per wire is not to exceed 10 V, find the cross-sectional area of the distributor. Take \(\rho = 1.7 \times 10^{-6}\) Ω-cm.

A 100 km transmission line has a 1000 ohms shunt capacitive reactance. What is the capacitive reactance per km?

In what year was the first 500 kV line in the world became operational?

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.

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?

In transmission voltage levels, 765kV is categorized as

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?

Surge impedance of transmission line is given by

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?

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 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%.

An unconventional conductor consists of three strands arranged vertically. Find the GMR in terms of the radius r of an individual strand.

A string insulator has 4 units. The voltage across the bottom most unit is 30% of the total voltage. What is the string efficiency?

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.

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?

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.

Bundled conductors in EHZ transmission lines results to

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.

The surge impedance of an underground cable is around