Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 8th Sem New 2180903 Power System Planning And Design Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VIII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2180903 Date: 26/11/2018
Subject Name: Power System Planning and Design
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define the terms feeder, distributor and service mains. 03
(b) Discuss the following with respect to design of transmission line. (1) Choice
of voltage (2) Selection of conductor size
04
(c) Explain classification of lamp flicker and remedies for reducing lamp flicker.
07
Q.2 (a) Define critical disruptive voltage and visual critical voltage. 03
(b) Explain radio and television interference. 04
(c) For 1-? AC distributor A B C D of length 400m, determine the total voltage
drop over the distributor if various currents tapped are as under. (1) At point
B, 100m from A, 100amp at 0.707p.f. lagging (2) At point C, 250m from A,
120amp at UPF. (3) At point D, 400m from A, 80amp at 0.8p.f. lagging. Point
A is feeding point and impedance is (0.25+j0.125) per km run (go and return)
07
OR
(c) What is stringing chart? How the preliminary design of tower is carried out? 07
Q.3 (a) Define step potential, touch potential and transferred potential. 03
(b) Discuss the following with respect to design of transmission line. (1) span and
number of circuit (2) SIL
04
(c) A 3 core distribution cable is 300m long and supplies a load of 100kW at
440volts at 0.9p.f. lag for 3000hours in a year. The cable cost including
installation is Rs. (13a+32) per meter where ?a? is the cross sectional area of
each conductor in sq.cm. Cost of energy wasted is 12 paisa per unit and the
rate of interest and depreciation is 15%. The resistance per km of the
conductor of 1 cm
2
cross section is 0.213?. Find the most economical cross
? section of the distributor cable.
07
OR
Q.3 (a) Define earth electrode and earth current. 03
(b) Compare radial ? distribution system and ring ? distribution system. 04
(c) A 3 phase star connected system with 230V between each phase and neutral
has resistances of 4?, 5? and 6? respectively in three phases. Estimate the
current flowing in each phase and the neutral current. Find the total power
absorbed.
07
Q.4 (a) State limitations of Peek formula for calculating corona loss. 03
(b) What are the design considerations for EHV transmission line? 04
(c) Explain the factors while considering the size and locations of substation. 07
OR
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VIII (NEW) EXAMINATION ? WINTER 2018
Subject Code: 2180903 Date: 26/11/2018
Subject Name: Power System Planning and Design
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define the terms feeder, distributor and service mains. 03
(b) Discuss the following with respect to design of transmission line. (1) Choice
of voltage (2) Selection of conductor size
04
(c) Explain classification of lamp flicker and remedies for reducing lamp flicker.
07
Q.2 (a) Define critical disruptive voltage and visual critical voltage. 03
(b) Explain radio and television interference. 04
(c) For 1-? AC distributor A B C D of length 400m, determine the total voltage
drop over the distributor if various currents tapped are as under. (1) At point
B, 100m from A, 100amp at 0.707p.f. lagging (2) At point C, 250m from A,
120amp at UPF. (3) At point D, 400m from A, 80amp at 0.8p.f. lagging. Point
A is feeding point and impedance is (0.25+j0.125) per km run (go and return)
07
OR
(c) What is stringing chart? How the preliminary design of tower is carried out? 07
Q.3 (a) Define step potential, touch potential and transferred potential. 03
(b) Discuss the following with respect to design of transmission line. (1) span and
number of circuit (2) SIL
04
(c) A 3 core distribution cable is 300m long and supplies a load of 100kW at
440volts at 0.9p.f. lag for 3000hours in a year. The cable cost including
installation is Rs. (13a+32) per meter where ?a? is the cross sectional area of
each conductor in sq.cm. Cost of energy wasted is 12 paisa per unit and the
rate of interest and depreciation is 15%. The resistance per km of the
conductor of 1 cm
2
cross section is 0.213?. Find the most economical cross
? section of the distributor cable.
07
OR
Q.3 (a) Define earth electrode and earth current. 03
(b) Compare radial ? distribution system and ring ? distribution system. 04
(c) A 3 phase star connected system with 230V between each phase and neutral
has resistances of 4?, 5? and 6? respectively in three phases. Estimate the
current flowing in each phase and the neutral current. Find the total power
absorbed.
07
Q.4 (a) State limitations of Peek formula for calculating corona loss. 03
(b) What are the design considerations for EHV transmission line? 04
(c) Explain the factors while considering the size and locations of substation. 07
OR
2
Q.4 (a) Explain earthing grid. 03
(b) Enlist the steps to be followed for the construction of receiving end circle
diagram.
04
(c) Discuss the power system improvement scheme in detail. 07
Q.5 (a) What is insulation coordination? 03
(b) Write a note on location of lightning arrester. 04
(c) Explain main considerations in planning and designing generating stations in
power systems with reference to the following: (1) Size of units (2) Location
of power stations.
07
OR
Q.5 (a) Define dry flash over voltage, wet flashover voltage and impulse flash over
voltage.
03
(b) State limitations of Kelvin?s law. 04
(c) Explain main considerations in planning and designing generating stations in
power systems with reference to the following: (1) Role of different types of
power plants in large power systems. (2) Choice of generator unit constants.
07
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This post was last modified on 20 February 2020