20.a. A specific buried cable installation will use a duct with a maximum fill ratio of 31%. The outer diameter of the duct is 6 cm. What's the largest allowed diameter of the cable? A. 4.34 cm B. 1.86 cm C. 11.16 cm D. 1.36 cm 20.b. Two support messengers in an expansion loop are separated by 30 cm. What's the minimum bend radius for a cable routed through these support messengers? A. Exactly 15 cm B. Greater than 15 cm C. Less than 15 cm D. Exactly 30 cm

20.a. A specific buried cable installation will use a duct with a maximum fill ratio of 31%. The outer diameter of the duct is 6 cm. What's the largest allowed diameter of the cable? A. 4.34 cm B. 1.86 cm C. 11.16 cm D. 1.36 cm 20.b. Two support messengers in an expansion loop are separated by 30 cm. What's the minimum bend radius for a cable routed through these support messengers? A. Exactly 15 cm B. Greater than 15 cm C. Less than 15 cm D. Exactly 30 cm

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

Chapter4: Transmission Line Parameters

Section: Chapter Questions

Problem 4.46P

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Similar questions

For the case of double-circuit, bundle-conductor lines, the same method indicated in Problem 4.27 applies with r' replaced by the bundles GMR in the calculation of the overall GMR. Now consider a double-circuit configuration shown in Figure 4.36 that belongs to a 500-kV, three-phase line with bundle conductors of three subconductors at 21 in. spacing. The GMR of each subconductor is given to be 0.0485 ft. Determine the inductive reactance of the line in ohms per mile per phase. You may use XL=0.2794logGMDGMR/mi/phase
Expand 6k=13m=12Dkm.
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.
A 60-Hz, single-phase two-wire overhead line has solid cylindrical copper conductors with a 1.5 cm diameter. The conductors are arranged in a horizontal configuration with 0.5 m spacing. Calculate in mH/km (a) the inductance of each conductor due to internal flux linkages only, (b) the inductance of each conductor due to both internal and external flux linkages, and (c) the total inductance of the line.
Transmission line conductance is usually neglected in power system studies. True False
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.
Alumoweld is an aluminum-clad steel conductor. True False
The Aluminum Electrical Conductor Handbook lists a dc resistance of 0.01558 ohm per 1000 ft at 20C and a 60-Hz resistance of 0.0956 ohm per mile at 50C for the all-aluminum Marigold conductor, which has 61 strands and whose size is 1113 kcmil. Assuming an increase in resistance of 2 for spiraling, calculate and verify the dc resistance. Then calculate the dc resistance at 50C, and determine the percentage increase due to skin effect.
A single-phase overhead transmission line consists of two solid aluminum conductors having a radius of 3 cm with a spacing 3.5 m between centers. (a) Determine the total line inductance in mH/m. (b) Given the operating frequency to be 60 Hz, find the total inductive reactance of the line in /km and in/mi. (c) If the spacing is doubled to 7 m, how does the reactance change?
A 60-Hz, three-phase three-wire overhead line has solid cylindrical conductors arranged in the form of an equilateral triangle with 4-ft conductor spacing. The conductor diameter is 0.5 in. Calculate the positive-sequence inductance in Wm and the positive-sequence inductive reactance in /km.
A three-phase 60Hz line with a flat horizontal spacing uses conductors with a GMR of 0.0107 m, diameter of 3.27 cm, and a spacing between adjacent conductors of 10 m. Using ε0 = 8.8542 x 10-12, the capacitive reactance to neutral in ohm-meters is what?
A wind farm is being built on an island 6km offshore and needs to be connected to the power grid substation 12km down shore before it can become operational. The cost of laying cable under water is $10,000/km, and the cost of laying cable on land is $8,000/km. a) Determine the cable route that will minimize cost. b) What is the minimum cost