course planner subject power system planning and...

ELECTRICAL ENGINEERING DEPARTMENT

COURSE PLANNER

SUBJECT: POWER SYSTEM PLANNING AND

DESIGN [2180903]

B.E. – Fourth Year

Class–Electrical 2013

Term: 16/2 (DEC-16 to APR-17)

Faculty: PROF. J. I. JARIWALA PROF. P. T. PATEL

PROF. J. P. PATEL PROF. M. K. TAMBOLI

Contents: 1. Course Outcomes 2. Course Contents[Syllabus] 3. List of Reference Books 4. List of Experiments

5. List of Open source software and learning websites required for experiments

6. Active Learning Assignments and Tutorial. Instructions for Assignment/Tutorial:

[1] This set of Assignment-Tutorial consist the collection of questions of past GTU

Question papers.

[2] Attend those questions which are bold marked and/or frequently asked in GTU

exam.

[3] Students should make a separate Chapter wise Files[write on File Pages] to solve

these Questions.

[4] Students must solve these given set of Assignments by themselves only.

[5] Assessment of given assignment should be done regularly after completion of each

chapter by Students from the respective faculty members.


SUBJECT NAME: POWER SYSTEM PLANNING AND DESIGN

SUBJECT CODE: 2180903

COURSE OUTCOME (CO):

After learning the course the students should be able to:

1. Design transmission line (electrical and mechanical aspects)

2. Design primary and secondary distribution.

3. Selection of sizes and location of generating stations, substations.

4. Explain the basic concepts of power system earthing and measurement of

earthing resistance.

5. Explain the basic concepts of insulation co-ordination.

6. Explain the basic concepts and financial aspects of power system improvement.

7. Explain the basic concepts of generation planning, transmission planning and

distribution planning.


Course Contents:

CHAPTER

NO. SYLLABUS

Total

Hrs.

%

Weight

1

TRANSMISSION LINES DESIGN : Requirements of transmission lines, selection of voltage for high-voltage transmission lines, choice of conductors, spacing of conductors, corona, insulators, specifications of transmission lines, surgeimpedance loading of transmission lines, electrical design of transmission lines, main considerations in the mechanical design of transmission lines, sag-tension relation, stringing of transmission lines, towers Design of EHV transmission lines : transmission of electric power at extrahigh voltage, design considerations of EHV lines, selection and spacing of conductors, corona, radio and television interference, insulation coordination, towers[1]

10 20%

2

DESIGN OF DISTRIBUTION SYSTEMS : Development of a distribution plan, transmission and distribution systems, types of distribution systems arrangements, primary distribution design, secondary distribution design, distribution substations, calculation of distributor sizes: voltage drops, voltage regulation, Lamp flicker[1]

10 20%

3

DESIGN OF POWER SYSTEM : Introduction, selection of sizes and location of generating stations, selection and specifications of transmission lines, sizes and location of substations, interconnection[1]

6 8%

4

POWER SYSTEM EARTHING : Objectives, definitions, tolerable limits of body currents, soil resistivity, earth resistance, tolerable step and, actual step and touch voltage, design of earthing grid, concrete encased electrodes, tower footing resistance, measurement of earth resistance R, measurement of soil resistivity, impulse behavior of earthing system.[2]

5 15%

5

INSULATION CO-ORDINATION: Introduction, definitions, determination of line insulation, B.I.L and insulation levels of sub-station equipment, lightning arrester selection, power system overvoltages, tentative selection of arrestor voltage ratings, selection of arrestor discharge currents, arrestor discharge voltage, establishment of impulse voltage level of equipment, protective margin, establishment of separation limits, location of lightening arrestor[3]

5 15%

6

POWER SYSTEM IMPROVEMENT: Introduction, methods of power system improvement, power system improvement scheme, determination of the voltage regulation and losses in a power system, shifting of distribution transformer centre, financial aspects of the power system improvement scheme[1]

5 10%

7

POWER SYSTEM PLANNING: Introduction, methods of power system planning, forecasting load and energy requirements, generation planning, transmission system planning, distribution system planning, reliability of electrical power systems, methods of measuring power system reliability[1]

5 12%


Text Books: 1. Electrical Power System Design – M. V. Deshpande, TMH publication 2. Electrical Power System Design – B. R. Gupta, S. CHAND 3. A course in Electrical Power- Soni,,Gupta and Bhatnagar, DhanpatRai& Sons 4. Electrical Power System Planning – A. S. Pabla, TMH publication 5. Substation Design – Satnam& Gupta, DhanpatRai and Co


PRACTICAL LIST

Subject Code: 2180903

Subject Name:POWER SYSTEM PLANNING& DESIGN

SR.

NO. LIST OF PRATICALS

01 TO STUDY ELECTRICAL DESIGN OF TRANSMISSION LINE (PART-I).

02 TO STUDY ELECTRICAL DESIGN OF TRANSMISSION LINE (PART-II).

03 TO STUDY MECHANICAL DESIGN OF TRANSMISSION LINE (SAG AND SPAN

CALCULATION).

04 TO STUDY MECHANICAL DESIGN OF TRANSMISSION LINE (DESIGN OF

TOWER).

05 TO STUDY DESIGN OF DISTRIBUTION SYSTEM.

06 TO STUDY ABOUT PIPE EARTHING AND PLATE EARTHING. AND DESIGN OF

EARTHING SYSTEM.

07 TO STUDY DESIGN OF POWER STATION.

08 TO STUDY ABOUT INSULATION COORDINATION AND LOCATION OF

LIGHTNING ARRESTOR.

09 VISIT OF SUBSTATION AND DRAW ITS LAY OUT PLAN.

10 TO STUDY ABOUT SOME INDIAN STANDARDS RELATED TO DESIGN

PROBLEM.


Chapter-1 TRANSMISSION LINES DESIGN : Requirements of transmission lines, selection of voltage for high-voltage transmission lines, choice of conductors, spacing of conductors, corona, insulators, specifications of transmission lines, surgeimpedance loading of transmission lines, electrical design of transmission lines, main considerations in the mechanical design of transmission lines, sag-tension relation, stringing of transmission lines, towers Design of EHV transmission lines : transmission of electric power at extrahigh voltage, design considerations of EHV lines, selection and spacing of conductors, corona, radio and television interference, insulation coordination, towers[1]

ATTEMPT ANYSIX.

SR NO. QUESTION YEAR

MARK

S

1

What are corona losses? Discuss its significance and permissible limit. Explain Peek’s and Peterson’s formula for calculating the corona loss.

OR Define critical disruptive voltage and visual critical voltage. How Corona los can be determined? What is significance of Corona in the design of transmission line?

MAY

2012, 16 07

2 Discuss the following with respect to design of transmission line. (1) Choice of voltage (2) Selection of conductor size (3) Span and number of Circuit (4) SIL

MAY

2015 07

2

Discuss the following factors to be taken into consideration in the mechanical design of a transmission line. 1. Loading on the conductors. 2. Span, sag and tension. 3. Clearance from the ground.

MAY

2012 07

3 Explain the use of bundled conductors in EHV transmission lines. Also explain how the spacing, selection of size and number of conductors for the EHV lines is done.

MAY

2012 07

4 Define Surge Impedance Loading. Explain the significance of it in Transmission Line design.

SEP 2013 07

5 Explain the factors while considering choice and spacing of conductors for Transmission Line design.

SEP 2013 07

6 Differentiate between shunt and series compensation. SEP2013 07

7 Explain the Corona effects and loss with standard formula. SEP 2013 07

8 What are the design considerations for EHV transmission line? Explain radio and television interference.

JUNE 2014

07

10 Explain methods of reducing tower footing resistance JUNE 2014

07

11 Explain tuned power lines. JUNE 2014

07

12 What are corona losses? Explain Peek’s and Peterson’s formula for calculating the corona loss. What is the permissible limit?

DEC 2014 07


ATTEMPT ANY THREE.

13 What do you mean by compensation with refer to transmission line? Explain series compensation.

DEC 2014 07

14 Discuss the following factors to be taken into consideration in the mechanical design of a transmission line. (1) Clearance from the ground, (2) Earthing, (3) Span &sag

DEC 2014 07

15 Explain the factors while considering choice and spacing of conductors for transmission line design.

DEC 2014 07

16 Explain the design of cables considering the ampere capacity. DEC 2014 07

17 Explain the different types of EHV towers. List out the EHV systems in INDIA.

DEC 2014 07

18

What is a stringing chart? What method is used for stringing the line conductors on the supports? What is the effect of temperature and the modulus of elasticity on the tension of the line?OR What is stringing chart? How the preliminary design of tower is carried out?

MAY 2015,

16 07

19 Derive the sag-tension relation for a given span with towers at each end located at unequal levels.

MAY 2015

07

20 What is the effect of (1) stranded conductors, (2) bundled conductors (3) hollow conductors on corona?

DEC 2015

07

21 Explain the factors to be considered in selection of a voltage suitable for transmitting a certain amount of power at a given distance.

DEC 2015

07

22 Explain main considerations in mechanical design of Transmission line.

DEC 2015

07

23 Explain the use of bundled conductors in EHV transmission lines. Also explain how the spacing, selection of size and number of conductors for the EHV lines is done.

DEC 2015

07

SR

NO. QUESTION YEAR

MARK

S

1

An overhead transmission line conductor is subjected to a horizontal wind load of 1.78 kg/m and a vertical ice loading of 1.08 kg/m. If the maximum permissible sag is 6 meters and the ultimate strength is 7950kg, calculate the permissible spanbetween the two supports allowing a safety factor of 2. Weight of the conductor is 0.844 kg/m.

MAY 2012

07

2

It is proposed to transmit 100 MW at 0.9 power factor lagging over a distance of 200 km. Select the line voltage, number of circuits, proper conductor and span for this line making use of the tables attached and hence find the line parameters and line regulation.

MAY 2012

07

3

MAY 2012

07


For the problem mentioned in above estimate the corona loss and find the line efficiency. Make use of the tables attached. Table‐1.

Line to line voltage (kV)

Line loading ( kW‐km)

11 24 x 103 33 200 x 103 66 600 x 103 110 11 x 106 132 20 x 106 166 35 x 106 230 90 x 106

Table‐2.

Line to line voltage (kV)

Length of the line in km

Minimum Maximum 66 40 120 110 50 140 132 50 160 166 80 180 230 100 300

Table‐3.

Copper equivalent cross sectional area (cm2)

Safe current carrying capacity in Amp.

Copper conductors.

ACSR conductors.

0.1935 82 100 0.2580 102 127 0.3225 118 148 0.3870 135 170 0.4515 153 190 0.5160 170 210 0.5805 185 230 0.6450 200 255 0.9675 275 350 1.2900 340 425 1.6125 400 505 1.9350 460 580 2.2575 520 655 2.5800 570 715 2.9025 625 775


3.2250 670 825


4

Determine ABCD constants and Regulation of 3-phase Transmission line considering following data. Power = 85,000 kW, p.f.= 0.9 lagging, Distance = 160 km, Voltage = 230 kV, Spacing of conductors = 10.2 m , Resistance/km = 0.22 Ω, outer radius R = 0.827 cm, Self GMD = 0.768 R

SEP2013

DEC 2014

07

5

An overhead line is erected across a span of 250 m on level supports. The conductor has a diameter of 1.42 cm and a dead weight of 1.09 kg per meter. The line is subjected to a wind pressure of 37.8 kg per sq. m of the projected area. The radial thickness of ice is 1.25 cm. Calculate the sag. Assume a maximum working stress of 1050 kg per sq. cm. One cubic meter of ice weighs 913.5 kg.

MAY 2015

07

6

Design a transmission line to transmit three phase 90 MW at 0.95 power factor lagging, over a distance of 180 km. Choose the voltage, size of conductor and spacing between the conductors. Calculate the constants of the line and determine the regulation. Find the corona loss per kilometer of the line and the total corona loss.

Table 1 Line to line voltage (kV) Line loading ( kW-km)

11 24 x 103 33 200 x 103 66 600 x 103

110 11 x 106 132 20 x 106 166 35 x 106 230 90 x 106

Table 2

Copper equivalent

cross

Safe current carrying capacity in Amp.

sectional area

(cm2)

Copper conductors.

ACSR conductors.

0.1935 82 100 0.2580 102 127 0.3225 118 148 0.3870 135 170

MAY 2015

07


0.4515 153 190 0.5160 170 210 0.5805 185 230 0.6450 200 255 0.9675 275 350 1.2900 340 425 1.6125 400 505 1.9350 460 580 2.2575 520 655 2.5800 570 715 2.9025 625 775 3.2250 670 825

Table 3

Nominal Number of strands

and

Wire diameter.

Approx. Overall Diameter.

Calculated Resistance Per km at 20ºC.

Approx. total weight per km.

Calculated Breaking load of composite conductor

copper

area Aluminum

Steel

cm2 cm cm cm Ω kg kg

0.161 6/0.236 1/0.236 0.708 1.0891 106.2 954.8

0.322 6/0.335 1/0.335 1.005 0.5400 214.0 1864.3

0.387 6/0.365 1/0.365 1.097 0.4550 255.0 2204.5

0.484 6/0.409 1/0.409 1.227 0.3640 318.0 2742.0

0.645 6/0.472 1/0.157 1.417 0.2720 395.0 3311.2

0.645 7/0.439 7/0.193 1.458 0.2700 451.0 4152.6

0.805 30/0.236 7/0.236 1.654 0.2200 605.0 5764.0

0.968 30/0.259 7/0.259 1.814 0.1832 728.0 6883.0

1.125 30/0.279 7/0.279 1.956 0.1572 847.0 7953.0

1.290 30/0.299 7/0.299 2.073 0.1370 975.0 9098.0

1.613 30/0.335 7/0.335 2.347 0.1091 1218.0 11306.0

Table 4

Line to line

voltage

Equivalent spacing

(kV) (m) 11 1 33 1.3 66 2.6

110 5 132 6 166 8 230 10.2

Table 5

Self GMD or GMR of stranded conductors

Solid round conductor 0.779R


Full Stranding: 7 - strands 0.726R 19 - strands 0.758R 37- strands 0.768R 61- strands 0.772R 91- strands 0.774R 127- strands 0.776R

Table 6

Corona loss calculation E/Ed F 0.6 0.012 0.8 0.018 1.0 0.05 1.2 0.08 1.4 0.3 1.6 1.0

1.8 3.5 2.0 6.0 2.2 8.0

7

A 3-phase overhead line consists of three conductors in equilateral formation with 2.44 meter spacing. The conductor diameter is 1.04 cm and surface factor (m) is 0.85. The air temperature and pressure are 21.10 C and 74cm of mercury. Find visual critical corona voltage.

DEC 2015

07

8

It is proposed to transmit a three phase power of 100 MW at 0.9 p.f. lagging at 50 Hz over a distance of 200 Km. Voltage selected is 220 KV. ACSR GOAT conductor selected has specifications as 30/7/3.71mm, overall diameter 25.97 mm, current carrying capacity 680 amp and resistance at 20o C is 0.0898 ohm/Km.For conductor spacing of 6 mt and horizontal configuration of conductor, determine voltage drop and efficiency (neglect corona loss). Consider resistance for determining performance as 75oC .Take resistance temperature coefficient forconductor as 0.00438 at 0oC. Consider line as medium transmission line havingnominal pi configuration.

MAY 2016

07


Chapter-2

AC AND DC LOW TENSION DISTRIBUTION DESIGN: Development of a distribution plan, transmission and distribution systems, types of distribution systems arrangements, primary distribution design, secondary distribution design, distribution substations, calculation of distributor sizes: voltage drops, voltage regulation, Lamp flicker

ATTEMPT ANY FIVE.

SR

NO. QUESTION YEAR

MARK

S

1

Explain the following distribution systems with figures. 1. Radial system. 2. Parallel or loop system. 3. Network or grid system.

MAY 2012 07

2 What is lamp flicker? What are its causes? What type of loads are responsible for it? How can it be reduced?

MAY 2012 DEC2015

07

3 Discuss Kelvin’s law to find the most economical conductor size. What are the limitations of this law?

MAY 2012 07

4 Explain selection and size of feeders using Kelvin’s Law. SEP 2013 07

5 Explain the difference between Ring and Radial type Distribution System.

SEP 2013 07

6 Write a Short note on Lamp Flickering SEP 2013 DEC2014,

16

07

7 Discuss in detail the steps in planning and designing electrical distribution schemes.

SEP 2013 07

8 Discuss briefly the design consideration in distribution system. Define and explain the terms Feeder, Distribution and Service mains.

JUNE 2014

07

9 Explain classification of lamp flicker and remedies for reducing lamp flicker.

JUNE 2014

07

10 Explain the role of Kelvin’s law for the selection and size of feeders.

DEC 2014 07

11 Explain any one method of measuring soil resistivity and earthing resistance.

DEC 2014 07

12 Explain the following distribution system with figures. (1) Ring System (2) Network (Grid) system

DEC 2014 07

13 State and explain the law used to find the most economical conductor size. What are the drawbacks of this law?

MAY 2015 07

14 List and explain the types of primary distribution systems. MAY 2015 07

15 In a power system, sudden changes in the intensity of illumination of lamps is found. What is this phenomenon called? What are its causes? Suggest remedial measures if any.

MAY 2015 07

16 Write notes on (1) Lamp flicker (2) Difference between AC and DC LT distribution system design.

MAY 2016 07

17 Compare radial, ring and grid distribution system. State their applications,

DEC 2015 07

18 Explain the methods of designing primary distribution DEC 2015 07


system with reference to (1) Choice of voltage (2) Conductor size (3) Type of distribution system (4) Voltage drops.

MAY2016

19 State and explain Kelvin’s law for most economical conductor size with necessary derivation.

DEC 2015 07

ATTEMPT ANY SIX.

SR

NO. QUESTION YEAR

MARK

S

1

A single phase a.c. distributor 500 m long has a total loop impedance of (0.02 +j0.04) Ω and is fed from one end at 250 V. It is loaded as under: 1. 50 A at unity power factor, 200 m from the feeding point. 2.100 A at 0.8 power factor lag, 300 m from the feeding point. 3. 50 A at 0.6 power factor lag, at the far end. Calculate the total voltage drop in the distributor and the voltage at the far end.

MAY

2012 07

2

A two conductor street main AB, 500 meters in length is fed from both the ends at 250 V. Loads of 50 A,60 A, 40 A and 30 A are tapped at distances of 100 m,250 m, 350 m and 400 m from the end A respectively. If the cross section of the conductors is 1 cm2 and specific resistance of the material of the conductors is 1.7μ Ω-cm, determine the minimum consumer voltage.

MAY

2012 07

3

Find the most economical cross-section of a 3 core distributor cable 250 m long supplying a load of 80 kW at 400 V and 0.8 power factor lagging for 4000 hours per annum and open circuited for the remaining of the year. The cost of the cable including installation is Rs. (15a +25) per meter where ‘a’ is the area of each conductor in sq. cm. Interest and depreciation rate is 10 % and the cost of energy wasted is 10 paisa per unit. The resistance per km of the conductor of 1 cm2 cross section is 0.173 Ω.

MAY

2012 07

4

The following loads are connected to a three phase four wire 415/230 V distribution system. 1. A three phase 15 kW load at 0.9 power factor lagging. 2. A three phase 8 kW load at unity power factor. 3. A single phase 1.5 kW load at 0.8 power factor lagging between the phase R and neutral. 4. A single phase 3 kW load at 0.9 power factor leading between the phase Y and neutral. 5. A single phase 2 kW load at unity power factor between the phase B and neutral. The phase sequence is RYB. Calculate the currents in each line and current in Neutral.

SEP 2013 07

5

A 2 wire d.c. distributor AB is fed from both ends. At the feeding point A the voltage is maintained at 240 V and at B 245 V. The total length of the distribution is 200 meters and loads are tapped off as under : 25A at 50 meters from A; 50A at 75 meters from A; 30 A at 100 meters from A; 40 A at 150 meters from A. If the resistance per km of one conductor is 0.3 Ω., Calculate (1) The current in the various sections of distributor. (2) The minimum voltage and point at which it occurs.

JUNE 2014

07

6 A two conductor cable one km long is required to supply a constant load of 180 A throughout the year. The cost of cable is Rs (120 a + 60 ) per meter, where ‘a’ is the area of cross section of the conductor in

JUNE 2014

07


cm2 The cost of energy is 20 paise per KWh and interest and depreciation charges amount to 10 %. Resistivity of copper is 1.84 μΩ cm. Find the most economical cross section of the cable.

7

A 3 phase star connected system with 230 Volts between each phase and neutral has resistances of 4Ω, 5Ω and 6Ω respectively in three phases. Estimate the current flowing in each phase and the neutral current. Find the total power absorbed.

JUNE 2014

07

8

The following loads are connected to a three phase four wire 415/230 V distribution system. (1) A three phase 12 KW load at 0.85 power factor lagging. (2) A three phase 9 KW load at unity power factor. (3) A single phase 1.2 KW load at 0.85 power factor lagging between the phase R and neutral. (4) A single phase 2.5 KW load at 0.9 power factor leading between the phase Y and neutral. (5) A single phase 2 KW load at unity power factor between the phase B and neutral. The phase sequence is RYB. Calculate the currents in each line and current in Neutral.

DEC 2014 07

9

A 3 core distribution cable is 300 m long and supplies a load of 100 kW at 440 volts at 0.9 p.f. lag for 3000 hours 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 cm2crosssection is 0.213 ohm. Find the most economical cross-section of the distributor cable.

MAY 2015

07

10

A 2 wire DC distributor AB is 300 m long and is fed at both the ends A and B. The distributor supplies a uniformly distributed load of 0.25 A/m and concentrated loads of 40 A at C and 60 A at D. The distances AC and BD are 120 m each. The loop resistance of the distributor is 0.1 ohm/100m. Both A and B are maintained at 300 V. Find the currents fed at A and B and the potentials at points C and D.

MAY 2015

07

11

A single phase distributor has a resistance of 0.2 ohm and a reactance of 0.3 ohms. The voltage and current at the far end ‘B’ are 240 V and 100 A at 0.8 power factor lag respectively. At the mid-point ‘A’, the current is 100 A at 0.6 power factor lag with respect to the voltage at ‘A’. Find the supply voltage and the phase angle between the supply voltage and the voltage at the far end ‘B’.

MAY 2015

07

12

The daily load cycle of a three phase transmission line 20 Km long is equivalent to a current of 100 amp for 8 hrs, 75 amp for 7 hrs and 20 amp for 9 hrs. The capital cost per Km of line per conductor is Rs (9500 + 24000a) where ais cross sectional area in cm2 of the conductor. Find the most economical size for the conductor assuming interest and depreciation of 10 % per annum and cost of energy wasted is 5 paisa per KWh. Resistance of each conductor per Km length is 0.19/ a ohms

MAY 2016

07

13

For single phase AC distributor A B C D of length 400 mt ,determine the total voltage drop over the distributor if various currents tapped are as under . (1)At point B ,100 mt from A ,100 amp at 0,707 p.f. lagging (2)At point C ,250mt from A ,125 amp at UPF. (3)At point D , 400 mt from A ,80 amp at 0.8 p.f. lagging Point A is feeding point and impedance is (0.25 + j0.125 ) per Km run

MAY 2016

07


Chapter-3

DESIGN OF POWER SYSTEM : Introduction, selection of sizes and location of generating stations, selection and specifications of transmission lines, sizes and location of substations, interconnection.

ATTEMPT TWO.

SR

NO. QUESTION YEAR MARKS

1 Write a short note on Gas Insulated substation.

MAY 2012

SEP2013 DEC2015

07

2 Explain the factors while considering the size and locations of Sub Station.

SEP 2013 07

3 Discuss the consideration in the location of substation. JUNE2014 07

4 Name the equipment's you observe in large substation and explain the function of each.

JUNE 2014

07

5

What do you understand by a Gas Insulated Substation? Draw its circuit diagram. What are its advantages as compared to conventional substations?

MAY 2015

07

6 Draw substation layout. Explain each component of layout. DEC 2015 07

7 Explain the different issues related with interconnections between grid and Solar PV.

SEP2013 DEC 2015

07

8

Explain the main considerations in the planning and designing generating stations in power system with reference to the following (1 ) Size of unit (2) Location of power stations (3) Choice of generator unit constants

JUNE2014 DEC 2015

07

9

Explain the main considerations for planning and designing generating stations in power system with reference to (1) size of units (2) different types of generating plants (3) choice of generator reactance and constants.

MAY2016 07


Chapter-4

POWER SYSTEM EARTHING : Objectives, definitions, tolerable limits of body currents, soil resistivity, earth resistance, tolerable step and, actual step and touch voltage, design of earthing grid, concrete encased electrodes, tower footing resistance, measurement of earth resistance R, measurement of soil resistivity, impulse behavior of earthing system.

ATTEMPT ONE.

SR


1 Why are earth wires used? Discuss the methods used to improve the effectiveness of the earth wires.

MAY

2012 07

2 Explain station earthing system with earthing grid. JUNE 2014

07

3 Discuss steps for design of the earthing grid. MAY 2015

07

4 Explain touch potential and step potential. How to measure soil resistivity?

DEC 2015 07

5 Define earth electrode and earth current .Explain step potential,touch potential and transferred potential

MAY2016 07

6 What is earth resistance? Why its value should be as low as possible? How it is measured with voltmeter-ammeter method?

MAY2016

07


Chapter-5 INSULATION CO-ORDINATION: Introduction, definitions, determination of line insulation, B.I.L and insulation levels of sub-station equipment, lightning arrester selection, power system overvoltages, tentative selection of arrestor voltage ratings, selection of arrestor discharge currents, arrestor discharge voltage, establishment of impulse voltage level of equipment, protective margin, establishment of separation limits, location of lightening arrestor

ATTEMPT ONE.

SR


1 How is the selection of arrester voltage rating, discharge current and discharge voltage done?

MAY 2012 07

2 Define Insulation Coordination. Explain Insulation Co-ordination curves.

SEP 2013 07

3 Write a note on location of lighting arrestor. JUNE 2014 07

4 What is insulation coordination? Explain insulation levels of various substation equipment’s for 132 KV substations.

JUNE 2014 07

5 Define basic insulation level. Explain the insulation levels of substation equipment.

DEC 2014 07

6 Explain the working principle of Lightning Arrester. Explain the construction of Horn Gap type Arrester

DEC 2014 07

7 What feature is included in the design of transmission lines so that they are protected against the direct lightening strokes? Explain its working.

MAY 2015 07

8 Comment upon the location of the lightning arrester in a substation. Justify your answer.

MAY 2015 07

9 Explain (1) insulation coordination (2) BIL (3) selection of arrestor voltage rating (4) protective margin.

DEC2015 07

10 Explain the steps involve in the lightning arrestor selection. Highlight the effect of earthling for selecting voltage rating of the arrestor.

MAY2016 07

11 Define dry flash over voltage, wet flashover voltage and impulse flash over voltage.Explain the insulation coordination curve.

MAY2016 07


Chapter-6 POWER SYSTEM IMPROVEMENT: Introduction, methods of power system improvement, power system improvement scheme, determination of the voltage regulation and losses in a power system, shifting of distribution transformer center, financial aspects of the power system improvement scheme

SR

NO. QUESTION YEAR

MARK

S

1

What are the causes of high losses and poor-voltage regulation in a power system? What are the points to be considered in system improvement to bring it to normal operation with voltage regulation within limits and better efficiency?

*** 07

2

Explain the methods of system improvements with reference to improvement on L.T. system, 11 kV feeders, shunt compensation, transformer capacities, sub-transmission lines and new substations.

*** 07

3 How can you determine the voltage regulation of a loaded feeder with concentrated loads at given distances? Explain with illustration of a case on 11kV feeder.

*** 07

4 How lire the losses in the system determined before system improvement measures and after system improvement measures? Explain the effect of utilisation factor and loss-load factor.

*** 07

5

What are the considerations in locating the distribution transformer centres? In an overloaded system, how is the new location of distribution transformer centre determined by suitable shifting?

*** 07

6 What are the financial considerations to make the system improvement scheme viable? Explain with an illustration.

*** 07


Chapter-7 POWER SYSTEM PLANNING: Introduction, methods of power system planning, forecasting load and energy requirements, generation planning, transmission system planning, distribution system planning, reliability of electrical power systems, methods of measuring power system reliability

SR


1

Discuss the various methods of power system planning with reference to: (i) Load forecasting (ii) Generation planning (iii) Transmission line expansion planning

*** 07

2 Explain the methods of transmission system planning. Indicate low diagram for computer program.

*** 07

3 State methods of distributionsystem planning with the help of computers. Explain in brief

*** 07

4

Explain the importance of planning power systems with reliability consideration. What is meant by component reliability and power system reliability? How is the reliability measured?

*** 07

5

Describe the trends in power system planning in India with reference to : (I) Load forecasts, (ii) transmission line capacities, (iii) 400 kV transmission, (Iv) EHV, UHV and HVDC transmission, (v) Load despatching stations and their requirements.

*** 07

course planner subject power system planning and...

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