Problem. Problem 1. A 280-km, 380-kV, 50-Hz three-phase line has resistance of 0.06 Ohm/km, radius of each conductor of 18.7 mm. At full load, this line delivers 250 MW at 0.95 p.f. lagging and at 350 kV. Using nominal T circuit, find: 7.5 m 4 m 9.0 m 4 m a) Inductance per km of the system.] b) Capacitance per km with respect to neutral. c) Find the values of ABCD matrices of the system. d) The sending-end voltage and current. e) Find values for a) and b) in per-unit values. f) Find the overall voltage drop over the transmission distance of the system. 5 g) Calculate efficiency of the line from the sender to the receiver ends. h) Plot power triangles for the system and analvse power factor of the system.

Problem. Problem 1. A 280-km, 380-kV, 50-Hz three-phase line has resistance of 0.06 Ohm/km, radius of each conductor of 18.7 mm. At full load, this line delivers 250 MW at 0.95 p.f. lagging and at 350 kV. Using nominal T circuit, find: 7.5 m 4 m 9.0 m 4 m a) Inductance per km of the system.] b) Capacitance per km with respect to neutral. c) Find the values of ABCD matrices of the system. d) The sending-end voltage and current. e) Find values for a) and b) in per-unit values. f) Find the overall voltage drop over the transmission distance of the system. 5 g) Calculate efficiency of the line from the sender to the receiver ends. h) Plot power triangles for the system and analvse power factor of the system.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter5: Transmission Lines: Steady-state Operation

Section: Chapter Questions

Problem 5.11P: A 40-km, 220-kV, 60-Hz, three-phase overhead transmission line has a per-phase resistance of...

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The capacitance of a single-circuit, three-phase transposed line with the configuration shown in Figure 4.38, including ground effect, and with conductors not equilaterally spaced is given by C20lnDeqrlnHmH8 F/mÂ line-to-neutral where Deq=D12D23D133=GMD r= conductors outside radiusHm=(H12H23H13)1/3HS=(H1H2H3)1/3 Now consider Figure 4.39 in which the configuration of a three-phase, single circuit, 345-kV line with conductors having an outside diameter of 1.065 in. is shown. Determine the capacitance to neutral in F/m, including the ground effect. Next, neglecting the effect of ground, see how the value changes.
Three ACSR Drake conductors are used for a three-phase overhead transmission line operating at 60 Hz. The conductor configuration is in the form of an isosceles triangle with sides of 20, 20, and 38 ft. (a) Find the capacitance-to-neutral and capacitive reactance-to-neutral for each 1-mile length of line. (b) For a line length of 175 mi and a normal operating voltage of 220 kV, determine the capacitive reactance-to-neutral for the entire line length as well as the charging current per mile and total three-phase reactive power supplied by the line capacitance.
Calculate the capacitance-to-neutral in F/m and the admittance-to-neutral in S/km for the three-phase line in Problem 4.18. Also calculate the line-charging current in kA/phase if the line is 110 km in length and is operated at 230 kV. Neglect the effect of the earth plane.
For either single-phase two-wire line or balanced three-phase three-wire line with equal phase spacing D and with conductor radius r, the capacitance (line-to-neutral) in F/m is given by Can=.
Figure 4.34 shows double-circuit conductors' relative positions in segment I of transposition of a completely transposed three-phase overhead transmission line. The inductance is given by L=2107lnGMDGMRH/m/phase Where GMD=(DABeqDBCeqDACeq)1/3 With mean distances defined by equivalent spacings DABeq=(D12D12D12D12)1/4DBCeq=(D23D23D23D13)1/4DACeq=(D13D13D13)1/4 And GMR=[ (GMR)A(GMR)B(GMR)C ]1/3 with phase GMRs defined by (GMR)A=[ rD11 ]1/2;(GMR)B=[ rD22 ]1/2;(GMR)C=[ rD33 ]1/2 and r is the GMR of phase conductors. Now consider a 345-kV, three-phase, double-circuit line with phase-conductors GMR of 0.0588 ft and the horizontal conductor configuration shown in Figure 4.35. Determine the inductance per meter per phase in Henries (H). Calculate the inductance of just one circuit and then divide by 2 to obtain the inductance of the double circuit.
For a single-phase two-conductor line with composite conductors x and y, express the inductance of conductor x in terms of GMD and its GMR.
A three-phase overhead transmission line is designed to deliver 190.5 M VA at 220 kV over a distance of 63 km, such that the total transmission line loss is not to exceed 2.5 of the rated line MVA. Given the resistivity of the conductor material to be 2.84108-m, determine the required conductor diameter and the conductor size in circular mils. Neglect power losses due to insulator leakage currents and corona.
The 100-km, 230-kV, 60-Hz, three-phase line in Problems 4.18 and 4.39 delivers 300 M VA at 218 kv to the receiving end at full load. Using the nominal circuit, calculate the ABCD parameters, sending-end voltage, and percent voltage regulation when the receiving-end power factor is (a) 0.9 lagging, (b) unity, and (c) 0.9 leading. Assume a 50C conductor temperature to determine the resistance of this line.
The 500-kV, 60-Hz, three-phase line in Problems 4.20 and 4.41 has a 180-km length and delivers 1600 M W at 475 kv and at 0.95 power factor leading to the receiving end at full load. Using the nominal circuit, calculate the (a) ABCD parameters, (b) sending-end voltage and current, (c) sending-end power and power factor, (d) full-load line losses and efficiency, and (e) percent voltage regulation. Assume a 50C. conductor temperature to determine the resistance of this line.
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