Distrubution of Power

PBR VISVODAYA INSTITUTE OF TECHNOLOGY

AND SCIENCE

Course File

IV Year B.Tech (EEE) I Semester

Contents

1. Syllabus

2. Objective

3. Lesson Plan

4. Question Papers Mid-semester examinations

5. Question Bank

6. Previous years question papers JNTUA

DISTRIBUTION OF ELECTRIC POWER

Syllabus

JAWAHARLAL NEHRU

TECHNOLOGICAL UNIVERSITY ANANTAPUR

B.Tech IV-I Sem. (E.E.E)

(9A02701) DISTRIBUTION OF ELECTRIC POWER

UNIT I GENERAL CONCEPTS Introduction to distribution systems, Load modelling and characteristics. Coincidence factor,

contribution factor loss factor - Relationship between the load factor and loss factor.

Classification of loads (Residential, commercial, Agricultural and Industrial) and their

characteristics.

UNIT II GENERAL ASPECTS OF D.C. DISTRIBUTION SYSTEMS Classification of Distribution Systems - Comparison of DC vs AC and Under-Ground vs Over -

Head Distribution Systems- Requirements and Design features of Distribution Systems- Voltage

Drop Calculations (Numerical Problems) in D.C Distributors for the following cases: Radial D.C

Distributor fed one end and at the both the ends (equal/unequal Voltages) and Ring Main

Distributor.

UNIT III A.C. DISTRIBUTION SYSTEMS

Design Considerations of Distribution Feeders: Radial and loop types of primary feeders, voltage

levels, feeder loading; basic design practice of the secondary distribution system. Voltage Drop

Calculations (Numerical Problems) in A.C. Distributors for the following cases: Power Factors

referred to receiving end voltage and with respect to respective load voltages.

UNIT IV SUBSTATIONS Location of Substations: Rating of distribution substation, service area within primary feeders.

Benefits derived through optimal location of substations. Classification of substations: Air

insulated substations - Indoor & Outdoor substations: Substations layout showing the location

of all the substation equipment. Bus bar arrangements in the Sub-Stations: Simple arrangements

like single bus bar, sectionalized single bus bar, main and transfer bus bar Double breaker One and half breaker system with relevant diagrams.

UNIT V POWER FACTOR AND VOLTAGE CONTROL Causes of low p.f -Methods of Improving p.f -Phase advancing and generation of reactive KVAR

using static Capacitors-Most economical p.f. for constant KW load and constant KVA type

loads, Numerical Problems. Dependency of Voltage on Reactive Power flow.- Methods of

Voltage Control: Shunt Capacitors, Series Capacitors, Synchronous Capacitors, Tap changing

and Booster Transformers

UNIT VI SYSTEM ANALYSIS Voltage drop and power-loss calculations: Derivation for voltage drop and power loss in lines,

manual methods of solution for radial networks, three phase balanced primary lines.

UNIT VII COMPENSATION FOR POWER FACTOR IMPROVEMENT Capacitive compensation for power-factor control - effect of shunt capacitors (Fixed and

switched), Power factor correction- Economic justification - Procedure to determine the best

capacitor location.

UNIT VIII PROTECTION AND COORDINATION OF DISTRIBUTION SYSTEMS Objectives of distribution system protection, types of common faults and procedure for fault

calculations. Protective Devices: Principle of operation of Fuses, Circuit Reclosures, line

sectionalizes, and circuit breakers Coordination of Protective Devices: General coordination

procedure.

TEXT BOOK:

1. Electric Power Distribution system, Engineering by Turan Gonen, Mc Graw-hill Book Company.

2. Electric Power Distribution by A.S. Pabla, Tata Mc Graw-hill Publishing Company, 4th edition, 1997.

Objective

DISTRIBUTION OF ELECTRICAL POWER

Course Objective

The distribution of electrical power course explains about the electrical engineering in

between the substation to the consumer end point. In this the design of substation and design of

electrical feeders in both primary and secondary networks, and the types of loads that the

customers having explained in detail. Similarly how to improve the reactive power with help of

capacitor banks and how to increase the power factor of the system with reduction of losses.

Lesson Plan

PBR VISVODAYA INSTITUTE OF TECHNOLOGY AND SCIENCE::KAVALI

DEPARTMENT OF EEE

LESSON PLAN

Academic Year: 2012 2013 CLASS: IV YEAR- I SEM

Faculty Name: A. BHAKTHA VACHALA S Subject: DISTRIBUTION OF ELECTRIC POWER

S.No

Dates

periods

In week

Topic to be covered

No. of

Periods

Requd.

Periods

Per unit

1

5

Unit I General Concepts: Introduction to

Distribution systems

Load modeling and characteristics - load forecasting

Coincidence factor, contribution factor &loss factor

Relation between loss factor and load factor

1

2

1

1

9

2 4

Classification of loads-residential loads

Commercial loads, agricultural loads

Industrial loads

2

1

1

3

5

Unit II: General Aspects of D.C Distribution:

Classification of distribution systems-Comparison

b between AC and DC Distribution, Under ground

And overhead distribution systems, requirements

And design features of distribution systems

2

1

1

1

4 5

Voltage drop calculations in dc distributors for the

Following cases: Radial distributor fed at one end

And at both ends and Ring main Distributor

2

2

1

10

5

5

Unit III: A.C. Distribution Systems

Design Considerations of Distribution Feeders:

a Radial and loop types of primary feeders, voltage

levels, feeder loading; basic design practice of the

secondary distribution system

2

1

1

1

9

6 4

Voltage Drop Calculations in A.C. Distributors for the

following cases: Power Factors referred to receiving end

voltage and with respect to respective load voltages.

2

1

1

7 4

Unit IV: Substations

Location of Substations: Rating of distribution

substation, service area within primary feeders.

Benefits derived through optimal location of

Substations

1

2

1

9

8

3

Classification of substations: Air insulated substations -

Indoor & Outdoor substations: Substations layout

showing the location of all the

substation equipment. Bus bar arrangements in the Sub-

Stations: Simple arrangements like single bus bar

1

1

1

1

9 5

sectionalized single bus bar, main and transfer bus

bar Double breaker One and half breaker system

1

with relevant diagrams

R evision for I Mid Exams

1

2

2

I MID EXAMINATIONS (03-09-2011 to 05-09-2011)

10

3

Unit V: Power Factor And Voltage Control

Causes of low p.f -Methods of Improving p.f -Phase

advancing and generation of reactive KVAR using static

Capacitors-Most economical p.f. for constant KW load

and constant KVA type loads, Problems

1

1

1

8

11

5

Dependency of Voltage on Reactive Power flow.-

Methods of Voltage Control: Shunt Capacitors,

Series Capacitors, Synchronous Capacitors, Tap

changing and Booster Transformers

2

1

1

1

12

5

Unit VI: System Analysis

Voltage drop and power-loss calculations: Derivation

for voltage drop and power loss in lines, manual

methods of solution for radial networks,

1

2

2

7

13

5

three phase balanced primary lines.

Problems

1

1

Unit VII: Compensation For Power Factor

Improvement: Capacitive compensation for power-

factor control - effect of shunt capacitors (Fixed and

switched),

1

1

1

5

Power factor correction-

Economic justification

2

1

14 Procedure to determine the best capacitor location.

Problems

1

1

8

15

5

Unit VIII Protection And Coordination Of Distribution

Systems:

Objectives of distribution system protection,

types of common faults and

procedure for fault calculations.

2

1

2

11

16

5

Protective Devices: Principle of operation of Fuses,

Circuit Reclosures, line sectionalizes, and circuit

breakers Coordination of Protective Devices: General

coordination procedure.

1

1

2

1

17

2

Problems 1

Discussion on previous Question Papers

And Revision

18

3

Revision for II Mid Exams

3

Total Available

78

Total Required

74

Signature of the staff-in charge Signature of the HOD

Question Papers Mid-semester

examinations

PBR VISVODAYA INSTITUTE OF TECHNOLOGY AND SCIENCE: KAVALI

IV. B.Tech, I-Sem, I-Mid Examinations, September - 2012

Branch: EEE Date: 03/09/2012(FN)

SUB: Distribution of Electrical Power Time: 90 Min

***Answer any three questions Maximum Marks 30

***All questions carry equal marks

1. (a) Prove that approximate formula for loss factor (FLS) = 0.3FLD + 0.7F2

LD, where FLD = load

factor.

(b) The annual average load is 1234 KW and monthly peak load is 3600KW. Find the load

factor and loss factor by using approximate formula.

2. Derive the equations for voltage drop and power loss in a radial feeder with uniformly

distributed load fed at one end.

3. Consider the singe phase radial distributor shown in the following f figure

The magnitude of load currents, p.fs and distances are indicated in the figure. The resistance

and reactance of each wire are 0.1 ohm and 0.2ohms per km respectively. It is required to

maintain voltage at point B as 230L0 Volts, find

(a) voltage drop in the three sections

(b) total voltage drop in the feeder

(c) supply voltage, current and power factor

(d) KVA output of supply,

The p.f. angles of individual loads are w.r.t. voltage at point B.

4. (a) Explain the methodology to fix the rating of a distribution substation.

(b) Explain about benefits derived through optimal location of substation

5. (a) Explain the following terms

i. maximum demand

ii. coincident demand and

iii. non - coincident demand.

(b) Compare the four and six feeders patterns.


IV. B.Tech, I-Sem, I-Mid Examinations, September - 2012



1. Demand factor is the ratio of [ ]

a) maximum demand to connected load b) connected load to maximum demand

c) average demand to maximum demand d) maximum demand to average demand

2. The coincidence factor for lighting loads in domestic loads about.. [ ] a) 0.7 b) 0.8 c) 0.9 d) 1

3. Heavy industrial have demand factor of .. [ ] a) 0.7 b) 0.8 c) 0.9 d) 1

4. A feeder supplying 1 MW load to an area has peak load losses of 65 KW and supplies

2.704 million units is a year. The load factor is.. [ ] a) 0.4 b) 0.5 c) 0.6 d) 0.7

5. Cross section of the conductor is obtained, on the basis of volt drop for.. [ ] a) feeders b) distributors c) service main d) none of the above

6. The voltage most commonly used for the primary distribution is [ ] a)11 KV b) 440 V c) 13.2 KV d) 33KV

7. Which of the following power distribution system gives the better reliability [ ]

a) radial system b) ring-main system c) either (a) or (b) d) all of above

8. A uniformly-loaded distributor fed at one end only has power loss X watts, if the distributor is now fed both ends. [ ] a) X

2 b) X/4 c) X/2 d) X/3

9. Standard 3 phase 4 wire L.T distribution in India is [ ] A) 400V, 3-phase B) 11KV,3-phase c) 230 V 1-phase d) none

10. The conductors are designed based on its . [ ]

a) voltage drop b) current carrying capacity c) power rating d) losses

11. Single phase AC distribution with midpoint ground is used for.. [ ] a) rural low voltage systems b) urban areas c) metro high voltage d) rural high voltage

12. In solving AC networks and distributors, the resistances have to be replaced by [ ]

a) reactance b) admittance c) susceptance d) impedance

13. The device used under the no-load condition in the substation [ ]

a) relay b) circuit breaker c) isolator d) any one of them

14. In constant impedance loads the power is proportional to the square of [ ]

a) current b) voltage c) resistance d) power factor

15. According to the type of service, the distribution systems are

Ans:

16. Give the function of lightning arresters.

Ans:

17. Why auto transformers are used in the high rating substations?

Ans:

18.Define the function of substation and its purpose?

Ans:

19. What is meant by distribution substations?

Ans:

20. Define voltage square law?

Ans:


IV. B.Tech, I-Sem, II-Mid Examinations, November - 2012



***Answer any three questions Maximum Marks 30

***All questions carry equal marks

1. Voltage control and power factor correction why these are necessary in power systems?

What are the disadvantages of low voltage and low power factor of the system?

2. Derive the equation for load power factor for which the voltage drop is maximum in terms

of the parameters of the feeder.

3. (a) Explain the practical procedure to determine the best capacitor location.

(b)A single phase motor connected to a 240V, 50HZ supply takes 20A at a p.f. of 0.75 (1ag).

A capacitor is shunted across the motor terminals to improve the p.f. to 0.9(1ag). determine

the capacitance of the capacitor used.

4. (a) Explain fuse-fuse co-ordination.

(b) Explain fuse-circuit breaker co-ordination.

5. (a) Explain different types of faults that occur in distribution system and their probability.

Explain the procedure for calculation of fault current in L-L fault.

(b) Consider the three-phase four wire 416V secondary system with balanced per-phase loads

at A, B, and C shown in the figure. Determine the following:

a) Calculate the total Voltage drop,

b) Calculate the real power per phase for each load

c) Calculate the reactive power per phase for each load

d) Calculate the total (3-) KVA output and load power of the distribution T/F.


IV. B.Tech, I-Sem, II-Mid Examinations, November - 2012



1. The most economical power factor of a consumer is generally.. [ ] a) 0.8 b) 0.9 c) 1 d) 0.7

2. An over-excited synchronous motor on no load is known as [ ] a) Synchronous condenser b) capacitor c) inductor d) generator

3. Permissible voltage variation is.. [ ]

a) 6% b) 7% c) 4% d) 5%

4. The purposes of using the booster transformer is for.the voltage [ ] a) boosting b) bucking c) bucking &boosting d) reducing

5. Changing a 1- lateral to an equivalent 3- lateral the per unit voltage drop and power losses are approximately.. [ ] a) halved b) 3/4

th c) 6/3

th d) 1

6. According to Morrison, the return current in the neutral wire is.. [ ] a) In = 2 1 Ia b) In = 31 Ia c) In =4 1 Ia d) In = 1 Ia

7. When full capacity and reduced capacity neutrals are used, the valves of KR [ ]

a) 3, >3 b) 3,

a) dc motors b) synchronous motor c) induction motors d) special motors

10. Industrial heating furnaces such as arc and induction furnaces operate on.. [ ] a) very low lagging p.f b) very high lagging p.f c) unity p.f d) leading p.f

11. The main reason for low power factor of supply system is due to the use of [ ] a) resistive loads b) capacitive loads c) inductive load d) none

12. kVAr is equal to [ ] a) KW sin b) KW cos c) KW tan d) kilo watts

13. An over current device with a circuit-opening feasible member directly heated and

destroyed by the passage of over current through it [ ] a) circuit breaker b) fuse c) line sectionalizer d) recloser

14. Power fuses are employed above the voltage. [ ] a) 34.5 KV b) 33.6 KV c) 32.5 KV d) 30.5 KV

15. What is the probabilities of 2L-G and 3- faults are. and. [ ] a) 15% and 5% b) 10% and 5% c) 15% and 15% d) 10% and 15%

16. An automatic interrupting devices which are capable of breaking and reclosing

a circuit under all conditions [ ] a) automatic circuit breaker b) fuse c) recloser d) line sectionalizer

17. When is the shunt inductor compensation is required?

Ans:

18. What is the range of typical values of resistances of ground electrodes in 3-,4-wire system. Ans:

19. Does the system operate at unity power factor? If yes, justify?

Ans:

20. The maximum fault current is calculations are based on what assumptions?

Ans:

Question Bank


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-1

STAFF: A. BHAKTHAVATSALA DATE: 15/07/2012

1. Examine the present trend for the future distribution system planning.

2. (a) Explain the following terms

i. maximum demand

ii. coincident demand and

iii. non - coincident demand.

(b) Explain following factors

i. Contribution factor

ii. load diversity

iii. loss factor

3. (a) Prove that approximate formula for loss factor (FLS) = 0.3FLD + 0.7F2

LD, where FLD = load

factor.

(b) The annual average load is 1234 KW and monthly peak load is 3600KW. Find the load

factor and loss factor by using approximate formula.

4. (a) Explain the characteristics of residential, industrial and commercial loads.

(b) A distribution substation supplies the following loads: 15,000KW, 8,500 KW, 6000KW and

450 KW. The station has a maximum demand of 22,000KW. The annual load factor of

the station is 48%. Calculate:

(i) The energy supplied annually

(ii) The diversity factor and

(iii)Demand factor.

5. (a) Explain load modeling and their characteristics.

(b)The annual peak load of a substation is 5000KW and the total annual energy supplied

to the feeder is 15105 KWh. The peak demand occurs is demand due to A-C load then find

i) Annual average power demand.

ii) Annual load factor.

iii) Annual loss factor using approximate formula.

Objective Questions:

1. Demand factor is the ratio of ..maximum demand to connected load 2. Load duration curve is between. Load and time over which it occurs 3. The coincidence factor for lighting loads in domestic loads about..0.9

4. Load growth followslaw.power law or compound interest law 5. Load diversity is the difference between.. and,,, Ans: sum of the peak demands of the individual loads and coincident maximum demand

6. Small industrial motors work at power factor of .0.4 to 0.75 7. The laod in an area has load factor has 0.6, loss factor may be.0.432 8. Heavy industrial have demand factor of ..0.9 9.Domestic loads have power factor of .0.6 to 0.7 10. A feeder supplying 1 MW load to an area has peak load losses of 65 KW and

supplies 2.704 million units is a year. The load factor is..0.4


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-II


1. Explain the different types of distribution feeders. Also, state the advantages

and disadvantages of different feeders.

2. Derive the equations for voltage drop and power loss in a radial feeder with uniformly

distributed load fed at one end.

3. Explain classification of distribution systems.

4. A two wire 400 m long distributor is loaded as follows:

Meters from feeding point : 100 200 275 325 400

Load in Amps : 25 10 30 50 20

If the resistivity of the conductor is 1.5 X 10-8

-m, what must be the cross-section of each Conductor, in order that the voltage drop may not exceed 10v.

5. Explain about the Ring main or Loop distributor.


1.Cross section of the conductor is obtained, on the basis of volt drop for..Distributors

2. Conductors which carry bulk loads from a generating station or a substation are called

Ans: feeders

3. The number of circuits through which, a consumer is fed in a ring-main system is

Ans: 2

4. the total voltage drop is equal to that produced by the whole of the load assumed concentrated at

the midpoint, in DC two wire distributor..Fed at one end with uniform load

5.Thevenins theorem is used to solve..either dc or ac networks

6. The voltage most commonly used for the primary distribution is11 KV

7. A line which connects consumer to the distributor is.service main

8. which of the following power distribution system gives the better reliability

Ans: Ring-main system

9. A line which connects the distributor to the substation is called..feeder

10. A uniformly-loaded distributor fed at one end only has power loss X watts, if the distributor is now fed both ends.X/4


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-III


1. Draw the one line diagram of radial type primary feeder and mention the factors that

Influences the selection of primary feeder.

2. Consider the singe phase radial distributor shown in the following f igure

The magnitude of load currents, p.fs and distances are indicated in the figure. The resistance

and reactance of each wire are 0.1 ohm and 0.2ohms per km respectively. It is required to

maintain voltage at point B as 2306 00Volts, find

(a) voltage drop in the three sections

(b) total voltage drop in the feeder

(c) supply voltage, current and power factor

(d) KVA output of supply,

The p.f. angles of individual loads are w.r.t. voltage at point B.

3.(a) Explain various factors that influences the number of conductors and size of conductor of

Primary feeder.

(b) Distinguish between a feeder, distributor and service mains in a secondary distribution

system.

4. Explain single line diagram of a simple radial secondary distribution and explain design

practice of this system.

5. Explain about voltage drop calculation in A.C. distributor with respect to load voltages.


1. If the distribution line voltage is changed from 22 KV to 33KV, the power transmitted can be

Ans: Four Times

2. Single phase AC distribution with midpoint ground is used for..Rural low voltage systems 3.Standard 3 phase 4 wire L.T distribution in India is400V, 3-phase 4. %VD for underground cables estimated.Same as over head lines 5. A distribution transformer usually is a..delta-delta transformer 6. which of the following distribution systems is the simplest and has lowest installation cost Ans: Radial system

7. In solving AC networks and distributors, the resistances have to be replaced byImpedance 8. In a distributor fed at both ends with concentrated loads, the point of minimum potential

Always occurs at a..point .mid point

9. An interconnected system provides..greater security of service 10. The conductors are designed based on its .current carrying capacity


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-IV


1. (a) What are the various factors that are to be considered in selecting substation location?

(b) Compare the four and six feeders patterns.

2. Give the classification of different types of substations. State the advantages and

disadvantages of each substation.

3. How do you analyse a substation service area with `n' primary feeders.

4. Give the classification of different types of substations. State the advantages and disadvantages

of each substation.

5. (a) Explain the methodology to fix the rating of a distribution substation.

(b) Explain about benefits derived through optimal location of substation

Objective questions:

1. Define substation.

2. What is meant by transmission substation?

3. what is meant by sub transmission substation

4. What is meant by distribution substation?

5. what is meant by switching substation?

6. What is the function of an isolator?

7. What is the difference between circuit breaker and isolator?

8. what is the need of lighting arresters?

9. what is the need of instrument transformer?

s10. why auto transformer is used in the high rating substations?


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-V


Descriptive questions

1. Write short notes on any two methods of voltage control?

2. Voltage control and power factor correction why these are necessary in power systems?

What are the disadvantages of low voltage and low power factor of the system?

3. Derive the equation for most economical power factor for a constant KVA type loads.

4. Explain various methods of power factor control?

5. (a) Write about the importance of power factor correction.

(b) Explain how d series capacitor boosts the voltage with the help of a phasor diagram.

What are the drawbacks of this method?

Objective questions

1. The major reason for low lagging power factor of supply system is due to the use

of.motors (Induction motors)

2. The most economical power factor of a consumer is generally..(Unity)

3. An over-excited synchronous motor on no load is known asSynchronous condenser)

4. A disadvantage of synchronous condenser.. (continues losses in motor, high maintenance cost, noisy)

5. Low voltage reduces the from incandescent lamps (light output)

6. Permissible voltage variation is..(+ or - 5%)

7. The excitation-control method is only suitable for.lines (short)

8. An over excited synchronous machine operated as generator or motor generates(KVAr)

9. Disadvantages of shunt capacitors are.. (fall of voltage, reduction in VArs, reduction in effectiveness)

10. The purposes of using the booster transformer is for.the voltage (bucking and boosting)


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-VI


1. (a) Write short notes on three phase balanced primary lines.

(b) What are the different types of manual methods used for the solution of radial networks?

Explain them.

2. Obtain an approximate voltage drop and power loss expression for primary feeder.

3. Derive the equation for load power factor for which the voltage drop is maximum in terms

of the parameters of the feeder.

4. Consider the three-phase four wire 416V secondary system with balanced per-phase loads at

A, B, and C shown in the figure. Determine the following: a) Calculate the total Voltage Drop,

b) Calculate the real power per phase for each load c) Calculate the reactive power per phase for

each load d) Calculate the total (three-phase) kilovoltampere output and load power of the

Distribution Transformer.

5. An unbalanced 3- star connected load is connected to a balanced 3- 4-wire system. The load impedances are ZR, ZY and ZB are 6030

o , 80-45o and 5035o per phase

respectively. and the line voltage has an effective value of 13.8kv. Use line to neutral of

phase R as the reference, determine the line and neutral currents and total active and reactive losses.


1. In a 1-, 2-wire lateral with ungrounded neutral, the current in the 1- lateral is larger than one in the equivalent 3- lateral (1.73) 2. The voltage drop in the 1- ungrounded neutral is approximatelytimes larger than the One in the equivalent 3- lateral (3.46) 3. Changing a 1- lateral to an equivalent 3- lateral the per unit voltage drop and power losses Are approximately..(Halved) 4. The voltage drop in the 1- , 2-wire uni-grounded lateral with full capacity neutral is...times larger than the one in the equivalent 3- , 4-wire balanced lateral (6 times) 5. The power loss due to load currents in the conductors of the 1- , 2-wire uni-grounded lateral with full capacity neutral is...times larger than the one in the equivalent 3- , 4-wire balanced lateral (6 times)

6. According to Morrison, the return current in the neutral wire is.In = 1 Ia 7. When full capacity neutral is used KR = 3, when a reduced capacity neutral is used KR > 3.

8. The most commonly used system due to its economic and operating advantages(3-,4-wire) 9. The point of minimum potential for a uniform distributor, fed at one end is at(the far end) 10. Floating neutral in a 3- supply is considered undesirable as it causes..

(unequal line voltages across the load)


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-VII


1. (a) Compare and explain the role of shunt and series capacitors in P.F. correction.

(b) A 400V, 50 cycles three phase line delivers 207KW at 0.8p.f. (lag). It is desired to

bring the line p.f. to unity by installing shunt capacitors. Calculate the capacitance

if they are i. star connected

ii. delta connected.

2. A 3-phase transformer rated 7000KVA and has a over load capability of 125% of the rating. If

the connected load is 1150KVA with a 0.8 pf (lag), determine the following :

(a) The KVAR rating of shunt capacitor bank required to decrease the KVA load of the

transformer to its capability level,

(b) the p.f. of the corrected level,

(c) the KVAR rating of the shunt capacitor bank required to correct the load p.f.to unity.

3. (a) Compare shunt and series capacitor schemes of compensation.

(b) A synchronous motor having a power consumption of 40KW is connected with a load of

150KW, a lagging p.f. of 0.8. If the combined loads has a power factor of 0.9. What is the

leading reactive KVA supplied by the motor and at what p.f. is it working?

4. (a) Explain the practical procedure to determine the best capacitor location.

(b)A single phase motor connected to a 240V, 50HZ supply takes 20A at a p.f. of 0.75 (1ag).

A capacitor is shunted across the motor terminals to improve the p.f. to 0.9(1ag). Determine

the capacitance of the capacitor used.


1.The smaller the lagging reactive power drawn by a circuit, its power factor will be(better) 2.kVAr is equal to(KW tan) 3. Synchronous capacitors are normally .cooled (air) 4. The power factor improvement equipment is always placed . (near the apparatus responsible for low power factor)

5. The phase advancers are used to improve the power factor of . (induction motors) 6. A machine designed to operate at full load is physically heavier and is costlier if the operating

power factor is..(lagging) 7. Industrial heating furnaces such as arc and induction furnaces operate on..(very low lagging p.f) 8. To improve the power factor of three-phase circuits, the size of each capacitor when connected in delta

With respect to when connected in star is. ( 1/3rd) 9. The maximum value of power factor can be.. (unity)

10. The main reason for low power factor of supply system is due to the use of..(inductive

load)


DEPARTMANT OF EEE

SUB: Distribution of Electric Power ASSIGNMENT-VIII


1. (a) What are the main objectives of distribution protection? Discuss.

(b) The per unit values of positive, negative and zero sequence reactances of a network at fault

are 0.08, 0.07 and 0.05 respectively. Determine the fault current if the fault is double line

to ground.

2. (a) Explain the operation of lines sectionalizer with a neat circuit diagram.

(b) Explain the operation of a circuit breaker with a neat sketch

3. (a) Explain fuse-fuse co-ordination.

(b) Explain fuse-circuit breaker co-ordination.

4. Discuss the procedure for fault current calculation in the following faults:

(a) 3-phase fault (b) Single line ground fault (c) Double line ground fault (d) Line-Line fault.

5. Explain general coordination procedure and discuss different types of coordination of protective.

6. (a) Explain the construction and principle of operation of fuses used in distribution system.

(b) Explain Recloser - Recloser condition.

7. (a) Explain the principle of operation of circuit breaker.

(b) Explain different types of faults that occur in distribution system and their probability.

Explain the procedure for calculation of fault current in L-L fault.


1. An over current device with a circuit-opening feasible member directly heated and destroyed

By the passage of over current through it(fuse) 2. Fuses designed to be used above 600V are categorized as.(distribution cutouts) 3. The speed ratio of fuses is defined... (melting current at 0.1sec / melting current at 300 or 600 sec)

4. Power fuses are employed above the voltage.(34.5 KV) 5. An over current protective device that automatically trips and recloses for a preset number of times

to clear temporary faults or isolate permanent faults..(Automatic Circuit Reclosers) 6. What is the probabilities of 2L-G and 3- faults are. and. (10% and 5%) 7. An automatic interrupting devices which are capable of breaking and reclosing a circuit under

All conditions.(automatic circuit breaker) 8. An over current protective device installed only with backup circuit breakers or reclosers. (automatic line sectionalizers)

9. Define the process coordination of protective devices.

10.Give the primary objectives of the distribution of system protection

Previous years question papers JNTUA

1 (a) A 50 MW hydro generator delivers 320 million KWh during the year. Calculate the plant load factor.

(b) Explain the load characteristics of distribution system.

2

(a)

Distinguish between primary and secondary distribution systems with suitable examples.

(b) A 2-wire DC distributor AB, 600m long as loaded as under: Distance from (mts): 150 300 350 450 loads (Amps): 100 200 250 300. The feeding point A is maintained at 440V and that of B at 430V. If each conductor has a resistance of 0.01 per 100 m, calculate i. The currents supplied from A to B.

ii. The power dispatched in the distributor.

3

(a)

Classify different types of primary feeders and give their merits and demerits.

(b) Derive the condition of load factor for which the voltage drop is maximum.

4

(a)

What are the factors to be considered for selecting location of substations?

(b) Explain the single bus bar system with sectionalization and what are its merits and demerits.

5

(a)

Explain the effect of shunt compensation on distribution system.

(b) A 3-phase substation transformer has a name plate rating of 7250KVA and a thermal capability of 120 of the name plate rating. If the connected load is 8816KVA with a 0.85pf lagging p.f., determine the following:

(i) The KVAR rating of the shunt capacitor bank required to decrease the KVA load of the transformer to its capability level.

(ii) The power factor of the corrected level.

6

Show that power loss due to load currents of the two phase, 3 wire lateral with full capacity neutral is exactly equal to 2.25 times larger than the one in which equivalent three phase lateral is used. Also prove that VD pu, 2 =2.1xVDpu, 3 for the above system.

7

(a)

Why the improvement of power factor is very important for both consumers and generating stations? List the various causes of low power factor and explain.

(b) A single-phase motor takes a current of 10 amps at a p.f. of 0.707 lagging from a 230V, 50 Hz supply. What value must a shunting capacitor have to raise the p.f. to unity.

8

(a)

Explain the salient points in general co-ordination procedure.

(b) Explain fuse-fuse coordination. *****

1 Discuss about different load modeling and their characteristics.

2

(a)

Discuss briefly the requirements of a distribution system.

(b) A 2-wire DC ring distributor is 300 m long and is fed at 240 V at point A. At point B, 150 m from A, a load of 120 A is taken and at C, 100 m in the opposite direction, a load of 80 A is taken if the resistance per 100 m of single conductor is 0.03, find

i. Current in each section of distributor ii. Voltage at points B and C.

3

(a)

Explain radial type primary feeder with neat diagram.

(b) Assume that feeder has a length of 2 miles and that the new feeder uniform loading has increased to 3 times the old feeder loading. Determine the new maximum length of the feeder with the same percent voltage drop if the new feeder voltage level is increased 34.5 KV from the previous voltage level of 12.47 KV.

4

(a)

Explain the main and transfer bus bar system with circuit diagram.

(b) What is the difference between single bus bar with and without sectionalization arrangement?

5

(a)

Write short notes on any two methods of voltage control.

(b) Voltage control and p.f correction are necessary in power systems. Explain. What are the disadvantages of low voltage and low p.f of the system?

6

A single phase line (ABC) of length 2 Km having resistance and reactance (go and return) as 0.06 and 0.1 ohms/Km. A is the feeding point, B is the mid-point of the line taking a load of 100A at 0.9 p.f leads and C is the far end taking a load of 12 A at UPF. The voltage at the C is 230V. Find the voltage at the sending end and the phase angle difference between the voltages of two ends. If

(a) Power factors of the loads are with reference to far end voltage. (b) Power factors of the loads are with reference to the voltages at the load

points.

7

(a)

How is economical p.f arrived at for a given distribution system with different loads?

(b) A 440 V, 50 cycles three phase line delivers 250 KW at 0.7 p.f (lag). It is desire to bring the line p.f to unity by installing shunt capacitors. Calculate the capacitance if they are: i. star connected

ii. delta connected.

8

(a)

What are the objectives of distribution system protection?

(b) What are the advantages and disadvantages of fuses?

*****

1 (a) Give the classification of loads and draw their characteristics.

(b) A load of 100 kW is connected at the riverside substation. The 15 min weekly maximum demand is given by 75 kW and the weekly energy consumption is 4200 kWh. Find the demand factor, the 15 min weekly load factor of the substation and its associate loss factor.

2

(a)

Write short notes on various systems of D.C distribution.

(b) Distinguish between a feeder, distributor and service main in a distribution scheme.

3

(a)

Classify different types of primary feeders and give their merits and demerits.

(b) Explain basic design practice of secondary distribution system and also discuss about secondary banking.

4

What are the different types of bus-bar arrangements used in sub-station? Illustrate your answer with suitable diagrams?

5

(a)

Define: i. Voltage regulation ii. Voltage drop iii. Nominal voltage iv. Rated voltage v. Utilization voltage vi. Maximum voltage vii. Minimum voltage

(b) Describe different types of equipment for voltage control with neat diagrams.

6

Derive the equation for voltage drop of square shaped service area of substation where the service area is provided with balanced load and lumped at different locations of laterals.

7

A 3-phase transformer rated 7000 KVA and has a over load capability of 125 of the rating. If the connected load is 11150KVA with a 0.8 pf(lag), determine the following:

(a) The KVAR rating of shunt capacitor bank required to decrease the KVA load of the transformer to its capability level.

(b) The p.f. of the corrected level. (c) The KVAR rating of the shunt capacitor bank required to correct the load p.f to

unity.

8

(a)

Explain fuse-circuit breaker coordination.

(b) Explain recloser-circuit breaker coordination. *****

*****

1 (a) Define coincidence factor and contribution factor.

(b) Obtain the relation between the load factor and loss factor.

2

(a)

Discuss the relative merits and demerits of underground and over head systems.

(b) An 800m distributor fed from both ends A and B is loaded uniformly at the rate of 1.2 A/m run, the resistance of each conductor being 0.05 per/km. Determine the minimum voltage and the point where it occurs if feeding points A and B are maintained at 255 V and 250 V respectively. Find also the current supplied from feeding point A and B.

3

Derive the total area served by four feeders is 0.667 times the total area served by six feeders if they are thermally loaded.

4

(a)

Explain the classification of substations according to design.

(b) What are the advantages and disadvantages of outdoor substation as compared to indoor substation?

5

(a)

How is economical p.f arrived at for a given distribution system with different loads?

(b) Discuss the effect of series capacitors on voltage control.

6

(a)

What are the different types of manual methods used for the solution of radial networks? Explain in detail.

(b) Derive the equation for load p.f for which the voltage drop is maximum.

7

(a)

Explain the disadvantages of low power factor.

(b) A single-phase motor connected to a 240V, 50 Hz supply takes 20 A at p.f. of 0.75 lag. A capacitor is shunted across the motor terminals to improve the p.f to 0.9 lag. Determine the capacitance of the capacitor to be used.

8

(a)

What is coordination? What is a protective device?

(b) Explain general coordination procedure. *****

*****

Digital Signal Processors

Syllabus

UNIT-I:INTRODUCTION

Introduction to digital signal processing: discrete time signals and sequences, linear shift invariant

systems, stability and causality, linear Constant coefficient difference equations. Frequency domain

representation of discrete time signals and systems.

UNIT-II:DISCRETE FOURIER SERIES

Properties of discrete Fourier series, DFS representation of periodic sequences Discrete Fourier

transforms: properties of DFT, Linear convolution of sequences using DFT, computation of DFT.Relation

between Z-Transform and DFS.

UNIT-III

FAST FOURIER TRANSFORMS

Fast Fourier transforms (FFT)-Radix2 decimation in time and decimation in frequency FFT algorithms

problems inverse FFT and FFT for composite N.

UNIT-IV:REALIZATION OF DIGITAL FILTERS

*****

Review of Z-transforms, applications of Z-Transforms, solution of difference equations of digital filters,

block diagram representation of linear constant-coefficient difference equations basic structures of IIR

systems, transposed forms, basic structures of FIR systems, system function.

UNIT-V:IIR DIGITAL FILTERS

Analog filter approximations-Butterworth and chebyshev, design of IIR digital filters from analog filters,

design examples analog-digital transformations, Illustrative Problems.

UNIT-VI :FIR DIGITAL FILTERS

Characteristics of FIR digital filters, frequency response. Design of FIR digital filters using window

techniques

frequency sampling technique,comparison of IIR and FIR filters, , Illustrative Problems.

UNIT-VII

MULTIRATE DIGITAL SIGNAL PROCESSING FUNDAMENTALS:

Basic sample rate alteration devices Multirate Structures for sampling rate Converters, Multistage

design of decimator and Interpolator,Polyphase Decomposition, Nyquist filters.

UNIT-VIII

APPLICATIONS OF DIGITAL SIGNAL PROCESSING

Spectral analysis of nonstationary Signals, Musical Sound processing, signal Compression,

Transmultiplexers, Discrete Multitone Transmission of digital data.

*****

Objective

The Importance of Digital Signal Processors (DSPs)

A signal is a piece of information in binary or digital form. Digital Signal Processing techniques improve

signal quality or extract important information by removing unwanted parts of the signal.

The introduction of general purpose microprocessors in the late 1970's and early 1980's made it possible

for DSP techniques to be used in a much wider range of applications. The microprocessors such as the

Intel x86 family were not suitable for the numerically-intensive requirements of digital signal processing,

and the increasing importance of DSP led major electronic manufacturers to develop DSP chips, the

design of which met all the requirements of digital signal processing.

DSP is a programmable chip and is capable of carrying out millions of floating point operations per

second. Typical DSP application fields are audio signal processing, video signal processing, image

processing and telecommunications devices. DSP is the basis of many technologies including mobile

phones, personal computers, video recorders, CD players, hard disc drive controllers and modems.

The application of digital signal processors in cellular phones is very significant. Signal compression, an

important application of DSPs, is used in cellular phones to permit a larger number of calls to be handled

simultaneously within each local "cell". The signal compression technology helps to communicate to one

*****

another by seeing them while talking. This facility is available with the help of a computer monitor, small

video camera and a conventional telephone line linking them together. DSPs can be used in applications

that require a high computational speed. Such applications include computer video boards and

specialized co-processor boards designed for intensive scientific computation.

Digital signal processors [http://www.fx-music.co.uk] account for a substantial proportion of the world

market for electronic devices. And therefore, the leading electronics manufacturers have invested

heavily in DSP technology.

Lesson Plan

PBR VISVODAYA INSTITUTE OF TECHNOLOGY AND SCIENCE, KAVALI

LESSON PLAN

YEAR: 2012 2013 BRANCH: EEE CLASS: IV.Tech./Isem

Name of the Faculty: Ms.M.Surekha Subject:Digital Signal Processing

S.No. Dates

No. of

periods

In week

Topic to be covered

No. of

Periods

required

Total

Periods

Per unit

1 5

UNIT-I:INTRODUCTION

Introduction to digital signal processing:

discrete time signals and sequences, linear

shift invariant systems

2

2

1

*****

2 4

stability and causality, linear

Constant coefficient difference equations.

2

2

12

3 5

Frequency domain representation of

discrete time signals and systems.

UNIT-II:DISCRETE FOURIER

SERIES

Properties of discrete Fourier series, DFS

representation of periodic sequences

1

2

1

1

09

4 5

Discrete Fourier transforms: properties of

DFT, Linear convolution of sequences

using DFT,

1

2

2

5 5

computation of DFT.Relation between Z-

Transform and DFS.

UNIT-III

FAST FOURIER TRANSFORMS

Fast Fourier transforms (FFT)-Radix2

decimation in time and

2

3

09

6 3

decimation in frequency FFT algorithms

problems

2

1

*****

7

4

inverse FFT and FFT for

composite N.

UNIT-IV:REALIZATION OF DIGITAL

FILTERS

Review of Z-transforms, applications of

Z-Transforms,

3

1

10

8 4

solution of

difference equations of digital filters,

block diagram representation of

linear constant-coefficient difference

equations

1

3

9 5

basic structures of IIR systems, transposed

forms, basic structures of FIR systems,

system function.

2

3

3.9.12 To 5.9.12 I-MID

10

1

UNIT-V:IIR DIGITAL FILTERS

Analog filter approximations-Butterworth

and chebyshev,

1

11 5

design of IIR

digital filters from analog filters, design

examples

2

2

1

12 4 analog-digital

*****

transformations, Illustrative Problems.

UNIT-VI :FIR DIGITAL FILTERS

Characteristics of FIR digital filters,

frequency response. Design of FIR

digital filters using window techniques

2 08

2

06

13 5

frequency sampling technique,

comparison of IIR and FIR filters, ,

Illustrative Problems.

UNIT-VII

MULTIRATE DIGITAL SIGNAL

PROCESSING FUNDAMENTALS:

Basic sample rate alteration devices

4

1

07

14 4

Multirate Structures for sampling

rate Converters, Multistage design of

decimator and Interpolator,

4

15 4

Polyphase Decomposition, Nyquist filters.

UNIT-VIII

APPLICATIONS OF DIGITAL

2

*****

SIGNAL PROCESSING

Spectral analysis of nonstationary

2

07

16 5

Signals, Musical Sound processing,

signal Compression, Transmultiplexers,

Discrete Multitone

Transmission of digital data.

2

2

1

17 3

II MID Revision

3

Total 72 72 72

Signature of Faculty Signature of HOD

*****

Question Papers Mid-semester

examinations

PBR

Visvodaya Institute of Technolo

*****

gy and Science

Class: IV/IV B.Tech. I-Sem. Branch: EEE I MID (Objective) Subject: DIGITAL SIGNAL

PROCESSING

Max Marks: 10 Time: 20 MIN Date: 03/09/2012(AN)

NAME: ROLL NO:

Answer all Questions

1) The system do not need memory for its operation is called [ ]

a) static system b)dynamic system c) stable system d) unstable system

2) LTI is called [

]

a) Linear transfer invariance b) Linear time invariance

c) Linear transfer impulse d) Linear time system

3) The signal x(n) is even is x(-n)=______ [

]

a) x(-n) b) x(n) c) -x(n) d) x(-n)

4) The signal x(n) is called energy signal if its [

]

a) energy is finite and power is infinite b) energy is finite and power is zero

c) power is finite and energy is infinite d) energy is finite

5) The system is causal [ ]

a) depends on future value b) past and present inputs

c) past inputs d) present and past inputs

6) FFT means ____________ [ ]

a) Fast Fourier Transform b) Fast Fast Transform c) Fourier Transform d) Fourier series

*****

7) What is the value of W164 [ ]

a) 0.707-j0.707 b) -j c) +j d) 0.707+j0.707

8) Number of complex additions required for calculating X(K) [ ]

a) N2-N b) N-1 c) N2 d) N

9) WN2 = _______ [ ]

a) WNK b) WN/2 c) WN

1 d) -WNK

10) Number of complex multiplications in 8-bit FFT are [ ]

a) 8 b) 4 c) 6 d) 12

11) DFS of x(n) _____________ [ ]

a) 2f b)X[K] c) x(n) d) X[K-K0]

12) Find period of x(n) =cos (n/3) [ ]

(a) 3 (b) 8 (c) 6 (d) n

13) WN is called ___________ [ ]

(a) Fourier transform (b) Fourier series (c) twiddle factor (d) IDFT

14) If the signal x(n) is periodic [ ]

a) x(n+N) b) x(n+N/2) c) x(n) d) x(n+2)

15) WNK = ___________________ [ ]

a)WN b)WNK c)WN

K+N/2 d) WN/2

16) ROC means _____________________________________________________

17) In Z-transform pair Z is called [ ]

(a) Imaginary (b) complex variable (c) Real variable (d) Real & Imaginary

*****

18) Unilateral Z-transform is [ ]

(a) n = 0 to (b) n= 0 to N-1 (c) n = -1 to -N (d) n = - to

19) The value of W83 = ________________________________

20)Zero padding means __________________________________________________

PBR VISVODAYA INSTITUTE OF TECHNOLGY AND SCIENCE :: KAVALI (Approved by A.I.C.T.E-

New Delhi, Affiliated to J.N.T. University, Anantapur) Janata peta, Kavali, S.P.S.R Nellore

(Dist), A. P

Subject Name: DSP Ist MID -Descriptive test Year & Branch:IV B.Tech -I Sem EEE

Answer any three questions. Each one carries 10 marks. 10X3=30

1. Check the following systems described with difference equations for linearity,shift invariance,

memory and causality.

a)y(n) = n x(n) b) y(n) = x(n)+x(n-1)+x(n-2)

2. Find the DFT of the sample data sequence x(n) = 1,1,2,2,3,3 and determine the corresponding

amplitude and phase spectrum

3. (a) What are Twiddle factors? Explain

*****

(b)Find DET of a sequence using DIT-FFT

x(n) = 1/2,1/2,1/2,1/2,0,0,0,0

4. Find inverse Z-transform of the following Z-transform using partial fraction expantion

(a) X(Z) =

( ) b) X(Z) =

( )( )

5. For a given periodic sequence, find Fourier series coefficients and corresponding magnitude and

phase of coefficients

Xp(n) = 1 ; for n = 0 to 4

0; otherwise



(Dist), A. P



1. Check the following systems described with difference equations for linearity,shift invariance,

memory and causality.

a)y(n) = n x(n) b) y(n) = x(n)+x(n-1)=x(n-2)



*****



x(n) = 1/2,1/2,1/2,1/2,0,0,0,0


(a) X(Z) =

( ) b) X(Z) =

( )( )



Xp(n) = 1 ; for n = 0 to 4

0; otherwise

PBR Visvodaya Institute of Technology and Science Class: IV/IV B.Tech. I-Sem. Branch: EEE II MID (Objective) Subject:

DIGITAL SIGNAL PROCESSING

Max Marks: 10 Time: 20 MIN Date: 01/10/2012(AN)

NAME: ROLL NO:

1. The phenomena of high frequency components acquiring the identity of low frequency components is

called ________________ [ ]

a)anti-aliasing b) aliasing c)sampling d) decimation

2.In chebyshev approximation, the normalized magnitude response has value of _________at the

cutoff frequency [ ]

*****

a)1/1+2 b)1/1+ 2 c)c/p d)p/c

3.The two propertics which are preserved in analog &digital transformation are__________ and

__________ [ ]

a) stability, causality b) stability ,linearity c) linearity ,causality d) linearity, static

4..At the cut-off frequency the magnitude of the butterworth filter is _______times the maximum value

[ ]

a)1/2 b)13 c) log102 d) 2(0.0707)

5. In ___________Window spectrum the width of mainlobe is triple the of rectangular window for same

value of N [ ]

a)Kaiser b)Triangular c)Blackman d)Hanning

6.In ____________window spectrum the sidelobe magnitude is variable [ ]

a)Hamming b)Blackman c)Kaiser d) Hanning

7. In FIR filters with constant phase delay in the impulse response is_____________ [ ]

a)antisymmetric b) magnitude c) symmetric d) phase

8. The linear phase FIR filter designed by chebyshev approximation technique is called [ ]

a)attenuation b)optimum equiriple design c)passband attenuation d)none

9. Bandpass signal is converted into lowpass signal with the help of ____________ [ ]

a)multiplication b)subtraction c)mixing d)division

10.Reducing the sampling rate by a factor D is _________________ [ ]

a)Alteration b)Interpolation c)Decimation d)spectrum

11.Subband coding means speech signal is divided into several frequency bands.These frequency band

_______________each other [ ]

a)overlap b)do not overlap c)half d)divide

12.Maximum frequency is changed from FX/2 to FX/2D.This is called _____________ [ ]

*****

a)aliasing b)sampling c)quantization d)modulation

13.Interpolation of two sub band makes their sampling rates _________________ [ ]

a)grater b)less c) equal d)double

14.Normally the length of the segment should be equal to [ ]

a)vocal tract b)pitch period c)long period d)short period

15.The DFT of the signal is valid if frequency ,amplitude and phase of each sinusoidal component is time

invariant and independent of length of signal such signals are called ________ [ ]

a)speech signal b)statinary signal c)nonstatinary siganl d)video signal

16.A shorter Window is used to get _______________spectrogram [ ]

a)narrow-band b)passband c)wideband d)stopband

17.STFT means ________________________________

18.The speech signal is generated by excitation of __________________ [ ]

a)short period b)long period c)vocal tract d)pitch period

19.The distortion in frequency axis due to nonlinear relationship between analog and digital frequency is

called_________________ [ ]

a) frequency warping b)attenuation in stopband

c) attenuation in passband d) uppercutoff frequency

20. 4.In linear phase filters when impulse response in antisymmetric and N is even, the magnitude

function is________________ [ ]

a)symmetric b) antisymmetric c) traction d)phase

*****



(Dist), A. P

Subject Name: DSP IInd MID -Descriptive test Year & Branch:IV B.Tech -I Sem EEE


1. Give the specifications p=8dB,s=16dB,fp=1KHZ and fs=2KHZ .Find the H(s) using chebyshev

approximation

2. (a) Explain the FIR filter design using windowing technique

(b)Compare FIR and IIR filters

3. Efficient implementation of Decimation,Interpolator

4. (a)What is trans multiplexer? What is its use?

(b) Discuss the few applications digital signal processing

5. Design highpass filter using Bartlett window with a cut-off frequency of 1.2 rad/sec and N=7

Consider

Hd(ejw) = e-jw for Wc

*****



(Dist), A. P



1. Give the specifications p=8dB,s=16dB,fp=1KHZ and fs=2KHZ .Find the H(s) using chebyshev

approximation

2. (a) Explain the FIR filter design using windowing technique

(b)Compare FIR and IIR filters

3. Efficient implementation of Decimation,Interpolator

4. (a)What is trans multiplexer? What is its use?

(b) Discuss the few applications digital signal processing

5. Design highpass filter using Bartlett window with a cut-off frequency of 1.2 rad/sec and N=7

Consider

Hd(ejw) = e-jw for Wc

*****

0 ; else where

also find H(ejw)

*****

Question Bank

VISVODATA TECHNICAL ACADIMIY

Dept : EEE Year : IV

Questions and bits from first four units

*****

Unit-I

1. The signal x(n) is called energy signal if its [ b ]

(a) energy is finite and power is infinite (b) energy is finite and power is zero

(c) power is finite and energy is infinite (d) energy is finite

2. The signal x(n) is called power signal if its [ c ]

(a) energy is finite and power is infinite (b) energy is finite and power is zero

(c) power is finite and energy is infinite (d) power is zero

3. The system is causal [ b ]

(a) Depends on future values (b) past and present inputs

(c) past inputs (d) present and future inputs

4. The system do not need memory for its operation is called [ a ]

(a) static system (b) dynamic system (c) stable system (d) unstable system

5. The system is dynamic of its output depends on ______________ [ d ]

(a) Past and present values (b) present value (c) Future value (d) past value

6. LTI is called [ b ]

(a) Linear transfer invariance (b) Linear time invariance

*****

(c) Linear transfer impulse (d) Linear time system

7. Linear time invariance system satisfies [ c ]

(a) Linearity invariance (b) Linearity system only

(c ) Linearity and time invariance (d) Invariance system

8. Digital signal is called [ b ]

(a) Amplitude is discrete (b) both amplitude and time is discrete

(c) ) time is discrete (d) ) phase is discrete

9. A system is non causal if the depends on [ b ]

(a) past value (b) future value (c) present value (d) out put value

10. The signal x(n) is even x(-n)= [ b ]

(a) x(-n) (b) x(n) (c) x(n) (d) x(-n)

*****

Unit-II

1 .The discrete time periodic signals are represented by [ a ]

(a) discrete Fourier series (b) discrete Fourier transform

(c) Laplace transform (d) Z- transform

2. The discrete time non periodic signals are represented by [ b ]

(a) discrete Fourier series (b) discrete Fourier transform

(c) Laplace transform (d) Z- transform

3. DFS of x(n) [ b ]

(a) 2f (b) X[K] (c) e (d) X[K-Ko]

4. find period of x(n) =cos (n/3) [ c ]

(a) 3 (b) 8 (c) 6 (d) n

5. WN is called ___________ [ c ]

(a) Fourier transform (b) Fourier series (c) twiddle factor (d) IDFT

*****

6. W83=________________ [ a ]

(a) 1/2 - j1/2 (b) j (c) j (d) 1

7. IDFT is [ b ]

(a) discrete Fourier transform (b) ) inverse discrete Fourier transform

(c) indirect DFT (d) standard signal

8. If the signal x(n) is periodic [ a ]

(a) x(n+N) (b) x(n+N/2) (c) x(n) (d) x(n+2)

9. Zero padding means [ b ]

(a) appending Zeros at the left of sequence (b) appending Zeros at the right of sequence

(c) middle of sequence (d) append one zero at the center

10. WNK+N/2 is equal to [ a ]

(a) -WNK (b) WN

K (c) WN/2K (d) WN/2

*****

Unit-III

1. FFT means [ a ]

(a) Fast Fourier Trans form (b) Fast Fast transform

(c) Fourier transform (d) Fourier series

2. Number of complex multiplications required for calculating X(K) [ c ]

(a) (N-1) (b) NxNxN (c) N2 (d) (N-1)N

3. Number of complex additions required for calculating X(K) [ a ]

*****

(a) N2-N (b) (N-1) (c) N2 (d) N

4. WNK+N = ____________ [ a ]

(a ) WNK (b) - WN

K (c) ) WNK+1 (d) ) WN/2

K

5. WN2 = _____________ [ b ]

(a) WNK (b) ) WN/2 (c) WN

1 (d) - WNK

6. Number of complex multiplications in 8-point FFT are [ d ]

(a) 8 (b) 4 (c) 6 (d) 12

7. Number of complex additions in 8-point FFT are [ b ]

(a) 8 (b) 24 (c) 6 (d) 12

8. What is the value of W164 [ b ]

(a) 0.707-j0.707 (b) -j (c) +j (d) 0.707+j0.707

9. DIT means [ b ]

( a ) Discrete in time (b) Decimation in time

(c) Decimation transform (d) Transform of time

10. DIF means [ a ]

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( a ) Decimation in frequency (b) Decimation in time

(c) Decimation transform (d) Transform of frequency

Unit-IV

1. ROC means_______________ [ a ]

(a) Region of convergence (b) Relation of convergence

(c) Relation oriented converge (d) Region oriented converge

2. Z-transform pair Z is called [ b ]

(a) Imaginary (b) complex variable (c) Real variable (d) Real & Imaginary

*****

3. What is the Z-transform of u (n) [ c ]

(a) Z/Z-a (b) 1/Z-1 (c) Z/Z-1 (d) Z-1

4. Scaling property in Z-domain an x(n) is [ a ]

(a) X[Z/a] (b) X[a/Z] (c) a X[Z] (d) a.1/z-1

5. BIBO means [ b ]

(a) boundary and boundary output (b) boundary input and boundary output

(c) un boundary output (d) boundary input

6. LTI system is BIBO stable if and only if the ROC of the system function includes__________

[ c ]

(a) Outer the circle (b) inner the circle (c) unit circle (d) origin

7. IIR means [ b ]

(a) i/p impulse response (b) infinite impulse response

(c) impulse impulse response (d) impulse ratio

8. FIR means [ b ]

(a) frequency impulse response (b) finite impulse response (c) impulse ratio

(d)infinite impulse ratio

9. Z-transform is an [ b ]

*****

(a) finite power series (b)infinite power series

(c) 2N power series (d) (N-1) power series

10. Unilateral Z-transform is [ a ]

(a) n = 0 to (b) n= 0 to N-1 (c) n = -1 to -N (d) n = - to

UNIT I

1. Check the following systems described with difference equations for linearity,

shift invariance ,memory and causality.

a)Y(n) = n x(n)

b) y(n) = x(n)+x(n-1)=x(n-2)

2. Describe all the characteristics of the system in detail

3 (a).Explain the concept of Digital signal processing

*****

(b)Advantages of Digital signal processing

4. Check whether the systems described by the following equations are causal

(a) y(n) = 3x(n-2)+3x(n+2) (b) y(n) = x(n-1)+x(n-2)

(c) y(n) = x(-n) (d) y(n) = 3y2 (n-1)-nx(n)+4x(n-1)-2x(n+1)

UNIT II

1. Determine the DFT of sequence x(n) = 1,1,0,0 and check the validity of answer by calculating IDFT



Xp(n) = 1 ; for n = 0 to 4

0; otherwise

3.State and prove following properties of DFS

(a) Linearity (b) periodic convolution (c) shift of sequence



*****

UNIT III

1.Discuss in detail the concept of decimation in time FFT.Also sketch the necessary flow graph for N=8

2. Given the sequences x(n) and h(n) below, compute the circular convolution using DIT-FFTalgorithm

x(n) = 1,1,1,1 h(n)=1,0,1,0



x(n) = 1/2,1/2,1/2,1/2,0,0,0,0

4. Draw the flow graph for 16-point radix-2 decimation in frequency FFT algorithm and explain it briefly

UNIT IV

1.Determine Z-transform ,ROC and Pole Zero locations of

(a) an u(n) (b) an(-n-1)

*****


(a) X(Z)=

( ) b) X(Z)=

( )( )

3. Realize FIR filter with system function in cascade form

H(Z)=1+(5/2)Z-1+2Z-2+2Z-3

4. Determine Z-transform of the following finite duration signals .Also find out ROC

(a) X1(n)=1,2,5,7,0,1 (b)X2=1,2,5,7,0,1

VISVODATA TECHNICAL ACADIMIY

Dept : EEE Year : IV/I

SUB:DSP

Questions and bits from V,VI,VII,VIII unit

UNIT-V

1.The two popular techniques used to approximate the ideal frequency response are__________ and

_______________ [ b ]

a)FIR &IIR b)butterworth&chebyshev c)linear & non linear d)none

2.The two propertics which are preserved in analog &digital transformation are__________ and

__________ [ a ]

*****

a) stability, causality b) stability ,linearity c) linearity ,causality d) linearity, static

3.The tolerance in the passband and stopband are called_____________ [ c ]

a) attenation b)amplification c) ripples d)phase distortion

4.In impulse invariant (or bilinear) mapping the poles on the imaginary axis in S-plane are mapped into

the ___________Z-plane [ a ]

a)unit circle b)inside circle c)out circle d)half of plane

5.The phenomena of high frequency components acquiring the identity of low frequency components is

called ________________ [ b ]

a)anti-aliasing b) aliasing c)sampling d) decimation

6.At the cut-off frequency the magnitude of the butterworth filter is _______times the maximum value

[ a ]

a)1/2 b)13 c) log102 d) 2(0.0707)

7.The type -2 magnitude response is also called ______________response [ c ]

a)butterworth b) chebyshev c)ripple d) none

8. The type -2 chebyshev approximation the magnitude response is monotonic in the _______ and equi

ripple in the _________ [ c ]

a)stopband,passband b)passband,stopband

c)uppercut off frequency d)lower cuttoff frequency

*****

9.In chebyshev approximation, the normalized magnitude response has value of _________at the

cutoff frequency [ a ]

a)1/1+2 b)1/1+ 2 c)c/p d)p/c

10.The distortion in frequency axis due to nonlinear relationship between analog and digital frequency is

called_________________ [ a ]

a) frequency warping b)attenuation in stopband c)

attenuation in passband d) uppercutoff frequency

UNIT-VI

1.Thefilter designed by using finite number of samples of impulse response are called___________

[ a ]

a)FIR filter b) IIR filter c)lowpass d) minimum samples

2.In FIR filters with constant phase delay in the impulse response is_____________ [ c ]

a)antisymmetric b) magnitude c) symmetric d) phase

3.The oscillations developed due to traction of impulse response is called _________ [ b ]

a)sustained oscillation b) Gibbs oscillation c)oscillation d) none

4.In linear phase filters when impulse response in antisymmetric and N is even, the magnitude function

is________________ [ a ]

a)symmetric b) antisymmetric c) traction d)

Distrubution of Power

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