ELECTROMAGNETIC FIELDS AND WAVES

FIELDS AND WAVES THIS IS A VERY IMPORTANT SUBJECT IN ELECTRICAL ENGINEERING. TO UNDERSTAND THIS CONCEPT, WE NEED TO STUDY SOME ENGINEERING ANALYSIS AND MATHEMATICS. IN THIS STUDY, SOME ASSUMPTIONS SHALL BE MADE. THESE ARE THAT THE STUDENT CAN STUDY ON HIS OR HER OWN. AS A RESULT, WE SHALL INTRODUCE THE STUDENT TO BASIC CONCEPTS AND HOPE THAT HE OR SHE CAN STUDY AND UNDERSTAND OTHER RELEVANT TOPICS. THIS COURSE IS DIVIDED INTO TWO. THE OUTLINE OF THE TWO COURSES WILL BE GIVEN. IT IS ASSUMED THAT THE FIRST COURSE HAS BEEN DONE SUCCESSFULLY. SOME TOPICS IN THE FIRST COURSE WILL TO ENABLE THE STUDENT TO STUDY AND UNDERSTAND THE SUBJECT MATTER PROPERLY. ELECTRO MAGNETIC FIELDS AND WAVES I Review of Electromagnetic laws Review of vector analysis Electrostatics Static electromagnetic field in Dielectrics and conductors Four Maxwell's equation Boundary Conditions Magnetostatics Direct Current Resistance Lorentz force Law Electromagnetic Conduction Magnetic Properties of Matters Qasistatics ELECTROMAGNETIC FIELDS AND WAVES II Electromagnetic Fields and waves II Maxwell's equations Maxwell's equations in integral form Time varying fields Retarded Potential Poisson's and Laplase equations Wave propagation Energy in electromagnetic waves Polynting Vector and Polynting theorems Nature of electromagnetic waves Wave guide Electromagnetic Radiation Antennas Ideal transmission line Standing Wave and standing wave ratio.

ELECTROMAGNETIC FIELDS AND WAVES

FIELDS AND WAVES THIS IS A VERY IMPORTANT SUBJECT IN ELECTRICAL ENGINEERING. TO UNDERSTAND THIS CONCEPT, WE NEED TO STUDY SOME ENGINEERING ANALYSIS AND MATEMATICS. IN THIS STUDY, SOME ASSUMPTIONS SHALL BE MADE. tHESE ARE THAT THE STUDENT CAN STUDY ON HIS OR HER OWN. AS A RESULT, WE SHALL INTRODUCE THE STUDENT TO BASIC CONCEPTS AND HOPE THAT HE OR SHE CAN STUDY AND UNDERSTAND OTHER RELEVANT TOPICS. THIS COURSE IS DIVIDED INTO TWO. THE OUTLINE OF THE TWO COURSES WILL BE GIVEN. IT IS ASSUMED THAT THE FIRST COURSE HAS BEEN DONE SUCCESSFULLY. SOME TOPICS IN THE FIRST COURSE WILL TO ENABLE THE STUDENT TO STUDY AND UNDERSTAND THE SUBJECT MATTER PROPERLY. ELECTRO MAGNETIC FIELDS AND WAVES I Review of Electromagnetic laws Review of vector analysis Electrostatics Static electromagnetic fiel in Dielectrics and conductors Four Maxwell's equation Boundary Conditions Magnetostatics Direct Current Resistance Lorentz force Law Electromagnetic Conduction Magnetic Properties of Matters Qasistatics ELECTROMAGNETIC FIELDS AND WAVES II Electromagnetic Fields and waves II Maxwell's equations Maxwell's equations in integral form Time varying fields Retarded Potential Poisson's and Laplase equations Wave propagation Energy in electromagnetic waves Polynting Vector and Polynting theorems Nature of electromagnetic waves Wave guide Electromagnetic Radiation Antennas Ideal transmission line Standing Wave and standing wave ratio.

A CALL BY GOD IS A CALL TO SERVICE AND DISCIPLESHIP

CALL TO SERVICE CALL TO DISCIPLESHIP CALL BY GOD TEXT GENESIS 12: 1-END AND GENESIS 13:1-4 STORY: CALL OF ABRAHAM ACTS 13:2 THE HOLY GHOST SAID, SEPARATE ME BARNABAS AND SAUL FOR THE WORK WHERE UNTO I HAVE CALLED THEM. ABRAHAM WAS CALLED. Vs. 1 He was called and given specific instructions. When God Calls you, He tells you what to do. Vs. 2,3 The call of God is accompanied with the blessings of God. These blessings are not limited to the called but also makes the called a blessing unto all. Vs. 4 Abraham obeyed. Abram was seventy and five years old when he departed. Vs. 5 When you are called, do not leave your family behind. Your family deserves to be saved to. Pray for them and talk to each member about Jesus Christ Vs. 6,7 In obedience, Abraham passed through the land and God made promises to him to give the land to hm and his seed. As you obey God today He will make you promises and will not fail. Abraham responded by building an alter unto the Lord God who appeared to Him. When you are called, respond in obedience and build God an alter in your heart. Worship Him always. Vs. 8 At every stage Abraham built an alter unto God. We must realize that worshiping God is important. Let us form the habit of worshiping God always. Vs. 9 As Abraham journeyed, there was famine. In life, we come across difficulties Vs. 10 Abraham went to Egypt. At Egypt he told a lie, to save his life. God did not like that. You do not need to tell a lie to save your life. He was rebuked. He took correction, took his wife and left Egypt. When he left Egypt, God prospered him. He went back to the place where he made an alter unto the lord; and there Abraham called on the name of the Lord. Abraham went back to God. When we repent, let us go back to God and call upon His holy Name. God will forgive us and receive us and prosper us.

PLEASE THE LORD ALWAYS

PLEASE THE LORD ALWAYS BELIEVE IN OUR LORD JESUS CHRIST TODAY AND LET YOUR WAYS PLEASE THE LORD.

LET US STUDY THE BIBLE TOGETHER AGAIN TODAY

LET US STUDY THE BIBLE TOGETHER AGAIN TODAY TEXT: MATTHEW 5:1-15 DEAR FRIEND THIS IS WHAT IS EXPECTED OF US AS CHRISTIANS. THE SPIRIT OF GOD IN US MAKES IT POSSIBLE FOR US TO PLEASE GOD. MAKE JESUS CHRIST YOUR FRIEND TODAY AND YOU WILL BE GLAD YOU DID. Matthew 5:1-15 King James Version (KJV) 5 And seeing the multitudes, he went up into a mountain: and when he was set, his disciples came unto him: 2 And he opened his mouth, and taught them, saying, 3 Blessed are the poor in spirit: for theirs is the kingdom of heaven. 4 Blessed are they that mourn: for they shall be comforted. 5 Blessed are the meek: for they shall inherit the earth. 6 Blessed are they which do hunger and thirst after righteousness: for they shall be filled. 7 Blessed are the merciful: for they shall obtain mercy. 8 Blessed are the pure in heart: for they shall see God. 9 Blessed are the peacemakers: for they shall be called the children of God. 10 Blessed are they which are persecuted for righteousness' sake: for theirs is the kingdom of heaven. 11 Blessed are ye, when men shall revile you, and persecute you, and shall say all manner of evil against you falsely, for my sake. 12 Rejoice, and be exceeding glad: for great is your reward in heaven: for so persecuted they the prophets which were before you. 13 Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men. 14 Ye are the light of the world. A city that is set on an hill cannot be hid. 15 Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house.

DISCIPLESHIP

Discipleship Text Luke 5:1- Jesus Christ made disciples. Who is a disciple of Jesus Christ? Let us take a look at the people Jesus Christ Chose and their responses. Peter: Peter toiled all night fishing and caught nothing. He worked hard mending his net ready for another days work. While he was at it, Jesus came along and made a request to use his boat. He obliged. He did not allow his disappointment as a result of his fruitless toil the night before to rob him of an opportunity to be of service to someone in need. Not only did Jesus Christ ask for his boat, he also asked him to paddle it further ashore. This he did. Note that there comes a time in the life of a disciple when Jesus Christ will ask you to do more even when it seems you are not making any progress despite all the effort you have expanded so far. Just obey Jesus Christ. He does not make mistake. Jesus Christ pays. Every good work has a reward and a blessing. To benefit from the blessings of god you must be obedient. You must obey God. You may have to choose between you faith and sound professional judgment. Peter was given an instruction to cast his net on the right hand side. As a disciple, Jesus Christ will give you instructions. These instructions may not be logical. Peter caught nothing all night and was asked to try again by Jesus Christ. Notice that Peter expressed his concerns and misgivings. Feel free to let God know how you feel sincerely, about instructions from God to you. Peter obeyed. Do not stop there, go ahead and obey God and He will bless you abundantly. Peter Obeyed and was blessed. Obey Jesus Christ today and you will be blessed. Others benefited from the blessings of God on Peter and Peter became a blessing. Peter acknowledged his limitations. Then Jesus Christ invited him to become a fisher of men. He accepted the offer. And left all and followed Jesus Christ. Are you willing to be a disciple of Jesus Christ today? Are you willing to leave all and follow Him? Do you want the gift or the giver? Jesus Christ is the giver of life. Accept Him Today and you shall be happy you did. James and John sons of Zebedee: These young men were proud of their father. They were willing to help their father at work. They worked hard. While at work, they came to the aid of Peter when he was being overwhelmed by the catch. Disciples of Jesus Christ are always willing to give a helping hand whenever the need arises. You must be born again. Jesus Christ is your Friend. Luke 5:1-11 (King James Version) Share on twitter Share on email Luke 5:1-11 King James Version (KJV) 5 And it came to pass, that, as the people pressed upon him to hear the word of God, he stood by the lake of Gennesaret, 2 And saw two ships standing by the lake: but the fishermen were gone out of them, and were washing their nets. 3 And he entered into one of the ships, which was Simon's, and prayed him that he would thrust out a little from the land. And he sat down, and taught the people out of the ship. 4 Now when he had left speaking, he said unto Simon, Launch out into the deep, and let down your nets for a draught. 5 And Simon answering said unto him, Master, we have toiled all the night, and have taken nothing: nevertheless at thy word I will let down the net. 6 And when they had this done, they inclosed a great multitude of fishes: and their net brake. 7 And they beckoned unto their partners, which were in the other ship, that they should come and help them. And they came, and filled both the ships, so that they began to sink. 8 When Simon Peter saw it, he fell down at Jesus' knees, saying, Depart from me; for I am a sinful man, O Lord. 9 For he was astonished, and all that were with him, at the draught of the fishes which they had taken: 10 And so was also James, and John, the sons of Zebedee, which were partners with Simon. And Jesus said unto Simon, Fear not; from henceforth thou shalt catch men. 11 And when they had brought their ships to land, they forsook all, and followed him. King James Version (KJV) PLEASE READ THE BIBLE EVERYDAY

LET US GO INTO THE SACTUARY OF GOD

BIBLE STUDY TIME TOPIC: LET US GO INTO THE SACTUARY OF GOD TEXT:PSALM 73: 1 - END MEMORY VERSE: PSALM 73:17 Vs 1 Truly God is good to Israel even to as are of a clean heart. Vs 2 DANGER He was almost gone. Vs 3 WHY For he was envious at the foolish when he saw the prosperity of the wicked Vs 4 For there are no bands in their dearth. Their strength is Firm. Vs 5 They are not in trouble as other men Vs 6 Therefore pride compasseth them as a chain Vs 7 They have more than heart could wish and their eyes stand out with fatness Vs 8 They are corrupt, and speak wickedly concerning oppression: They speak loftily. Vs 9 They set their mouth against the heavens and their tongue walketh through the earth Vs 10 Therefore his people return and waters of a full cup are wrong out to them. Vs 11 And they say, How doth God know? And is there knowledge in the most High? VS 12 Behold these are the ungodly who prosper in the world, they increase in riches. Vs 13 Verily I have cleansed my heart in vain and washed my hands in innocency. Vs 14 For all day long have I been plagued and chastened every morning. VS 16 It was too painful to me to know this. Vs 17 UNTIL I WENT INTO THE SANCTUARY OF GOD. THEN UNDERSTOOD I THEIR END. Vs 18 Surely thou didst set them in slippery places: thou castest them down into destruction Vs 19 How are they brought into desolation as in a moment they are utterly consumed with terrors. Vs 20 When one awakes so, O Lord, when thou awakest though shall despise their image. Vs 22 So foolish was I, and ignorant: I was as a beast before thee. Vs 23 Nevertheless I am continually with thou. Thou hast holden me by my right hand. Vs 24 Thou shall guide me with thy council, and afterward receive me in glory. Vs 25 Whom have I in heaven but thee? And there is none upon earth that I desire beside thee. Vs 26 God is the strength of my heart, and my portion forever Vs 27 People perish when they are far from God. Vs 28 It is good for me to draw near to God. I have put my trust in the Lord God, that I may declare all thy works. Believe in Our Lord Jesus Christ and You shall be saved. I THESSALONIANS 2: 10,12 Ye are witnesses, and God also, how holily and just and unblameably we behaved ourselves among you that believe: That ye walk worthy of God, who hath called you unto his kingdom and glory. Let us thank we God for this cause without ceasing. Thank you and God bless you.

LET US STUDY THE BIBLE TOGETHER

LET US STUDY THE BIBLE TOGETHER ROMANS 12 VS 1 Present your bodies a living sacrifice, holy, acceptable unto God Vs 2 be not conformed to this world - Be transformed - Renewing of your mind - To prove what is good - And acceptable - Perfect - Will of God Vs 3 be humble - Be sober Vs 5 we are one in Christ Vs 6 God gave us different gifts Vs 7 – 8 Use the gift of God well to do good. Anything that is worth doing is worth doing well - Let love be without dissimulation Vs 9 Abhor evil and cleave to good - Cleave to that which is good Vs 10 Be kind to each other Vs 11 Do not be Lazy - Fervent in spirit serving the Lord Vs 12 Rejoicing in hope - Patient in tribulation - Continuing instant in prayer Vs 13 Distributing to the necessity of saints - Given to hospitality. Vs 14 Bless them which Persecute you. - Bless and curse not Vs 15 Rejoice with them that do rejoice, and weep with them that weep Vs 16 Be of the same mind one toward another. - Mind not high things, but condescend to men of low estate. - Be not wise in your own conceits Vs 17 Recompense to no man evil for evil - Provide things honest in the sight of all men. Vs 18 If it is possible, as much as lieth in you live peaceably with all men. Vs 19 Dearly beloved, avenge not yourselves, but rather give place unto wrath: - For it is written, vengeance is mine; - I will repay saith the lord Vs 20 If your enemy is hungry feed him Vs 21 Overcome evil with good.

TRANSFORMER CALCULATION

TRANSFORMER CALCULATIONS A single phase transformer has 5000 turns on the Primary winding and 1250 turns on the Secondary. Winding resistances are r(1) = 4 ohms and r(2) = 0.25 ohms. Leakage reactances are x(1) = 16.0 ohms and x(2) = 1.0 ohms . The resistance load Z(2). If applied voltage at the terminals of the primary winding is 1200, find V(2) and the voltage regulation. Neglect magnetising current. Let 'a' be turns ratio. a = N(1) /N(2) = 5000/1250 = 4 R(1) = 4 + (0.25)(4)2 = 4+ (0.25*4*4) = 8 ohms X(1) = 16 + (1)(4)2 = 16+ (1*4*4) = 32 ohms Z'(2) = 24 (4)2 = 384 ohms I(1) = 1200/(384 + 8 + j32) = 1200/393.303954/- 4.6668 = 3.051075/-4.6668 aV(2) = I(1)Z'(2) = 3.051075/-4.6668 *384 =1171.6129/-4.6668 V(2) = aV(2)/a =(1171.6129/-4.6668)/4 = 292.90323/-4.6668 Voltage Regulation Is Given By [{|V(1)/a| -|V(2)|}/|V(2)| ] *100% {(1200/4 ) - 292.9 }/292.9 * 100% = 2.42% lagging

MORE PAST QUESTION PAPERS FOR REVISION

THESE QUESTIONS HAVE BEEN OBTAINED WITH THE EXPRESS PERMISSION OF THE LECTURER TEACHING THE COURSE FOR ACADEMIC PURPOSES. ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT DEPARTMENT OF ELECTRICAL/ELECTRONICS ENGINEERING SECOND SEMESTER EXAMINATION 2011/2012 SESSION ELECTRICAL POWER SYSTEMS ANALYSIS I. (EEE 454) TIME: 1Hr 30Min (Answer All Questions) NB: IF you have not done any continuous assessment, write down what you have learnt in about 120 words first. Basic Concepts What is Load Flow Analysis? What is State Estimation? What is Stability Studies? What is fault Anayisis? Outline the main types of faults you know with examples. What is a phasor? What is an active circuit. What is the relevance of Fault Analysis in Electrical Power System Engineer? What is symmetrical Components and what is it used for? How would you derive the Symmetrical Components of a set of three phase phasors given the original phasors? How does a synchronous generator work? Use this information to develop the model of a synchronous generator for Electrical Power System analysis. Explain your work. Develop the model of a transformer. What is the power of an ideal transformer and why? Develop the model of a long line. What are line parameters? What factors affect the resistance of a transmission line and why? Derive an expression for the capacitance of a transmission line. What is a Bus in Electrical Power Systems Engineering? What kinds of buses do you have in the Electrical Power System and what are their characteristics. What is Y=Bus matrix? What is it used for and how is it calculated? What is Per Unit System and give two reasons why it is used in Electrical Power Systems Analysis? Application The present government in Nigeria is under a lot of pressure to make Electric Power available to the people. What are your proposals in this regard? Given the ongoing privatization process, how will the Electrical Power System be affected by this exercise? Using your knowledge of this course, how would you ensure that there is improved power delivery subsequently? What measures would you put in place to ensure that standards are met and that the system operates effectively and efficiently? How would the problem of interconnectivity be solved? What is the national grid? How does it fit into the new market driven Electrical Power Delivery System? Compare this new system and the old and make appropriate suggestions and recommendations. How would you apply the result of Load flow analysis as an Electrical Engineer? Fault Analysis is very important in Electrical Power Systems Engineering. What is the relationship between Fault analysis, Electrical Power System Protection, Load Flow analysis and contingency provision in the event of an emergency situation? Calculations Derive an expression for Complex Power using Symmetrical Components. Compare this expression with the expression of Power using original phasors. Explain your work. Evaluate three phase complex power using these two expressions and compare your result. Explain your work; Given Vabc = Iabc = Explain the procedure calculating the Y-Bus Matrix. The transmission line in the figure below is 200km long and a 132kV line of the phase symmetric type. Calculate the Y Bus Matrix give that R = 0.057 Ω/km, ωL=0.357Ω/km, 1/ωC = 0.325MΩ/km

SHARE THE WORD OF GOD

GIVE THE BIBLE TO SOMEBODY TODAY. ENCOURAGE SOMEBODY TO READ THE BIBLE TODAY. READ THE BIBLE TODAY. PRAY TO GOD THROUGH JESUS CHRIST AS YOU READ AND SHARE HIS WORD. THANK YOU AND GOD BLESS YOU..

MORE PAST QUESTION PAPERS

THESE QUESTION PAPERS HAVE BEEN OBTAINED WITH THE EXPRESS PERMISSION OF THE LECTURER TEACHING THE COURSE FOR ACADEMIC PURPOSES. ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT DEPARTMENT OF ELECTRICAL/ELECTRONICS ENGINEERING SECOND SEMESTER EXAMINATION 2011/2012 SESSION ELECTRICAL SERVICES DESIGN. (EEE 451) TIME: 1Hr 30Min (Answer All Questions) NB: IF you have not done any continuous assessment, write down what you have learnt in about 120 words first. Basic Concepts Where would you place a protective device in a circuit or an installation in Electrical Services Design? What is the sequence of control for power supply to an installation or building for effective power delivery, safety and adequate control? Explain this sequence of Electric Power Supply Control with the aid of an illustration. Where would you place a switch in an installation or circuit in Electrical services design and why? What is regulation in Electrical services design and why is it important? What regulations are appropriate for Control, Distribution and Excess-Current Protection? What is a Consumer Control Unit? What is the difference between Close and Coarse excess-current protection and explain each of them. What is Diversity? What is a spur? What is the difference between a ring circuit and a radial circuit? Give an example of each and explain how each circuit would be protected and why? With the aid of a diagram, show how you would supply electrical energy to an installation by carrying out a simple two wire installation. What is earthing? What is bonding? What is the difference between the two? What is Candela? What is Illumination? Explain the inverse square law as it applies to Illumination. Explain the Cosine law as it applies to Illumination? What is Luminous intensity? What is Luminous flux? What is Lumen? How would you calculate Illumination using the Lumen Method? What is maintenance factor? What is Coefficient of Utilization? What tests are carried out at the end of an installation to ensure that the design objectives are met and that the installation is safe (List and explain five of these tests.)? Application What is the procedure for the Electrical Services Design of an Installation? What is Load Analysis? What is Bill of Quantities and how is it produced? At what stage is a Certificate issued and why? Design a Simple installation for an Engineering Exhibition and Conference Center to be located at the Capital-City center for international engineering exhibitions and conferences. Produce a Bill of Quantities. Show the Schematic diagram for Protection and Control of the various circuits in your design. Explain your work. What is the relevance of earthing in this installation? With the aid of relevant diagrams, explain how this will be done. In your electrical Services Design, make provision for the various facilities required to make the center functional. What is a cable? List five different cables you are likely to recommend, specify and use in this design and explain why you made these specifications? How would you carry out an investigation to determine the voltage drop as a result of a cable installation in your design? What will be the guiding regulation for this purpose and how would you go about this investigation? Calculation A toy assembly shop is 12m long, 8m wide and 4m up to truses is to be illuminated to a level of 180lux. The Utilization and Maintenance factors are respectively 0.9 and 0.7. Make a scale drawing of the plan of the shop and set out the required lighting points, assuming the use of tungsten lamps and dispersive metallic reflectors. You may assume a lamp efficiency of 15lm/W, and spacing height ratio of unity. Consider the suitability of a Cable 1mm2 (1/1.13) which has a voltage drop per ampere per meter run of 40mV, and a current rating of 11A for an installation for a walk way 100 meters long lit by 230V, 100W lamps spaced 10 meters apart and controlled by one switch at the supply end. The wiring is single-core P.V.C. insulated cables enclosed in metal conduit. Determine the suitability of this installation and make your recommendations in your report based on your investigation and analysis. Explain your work.

THESE WORDS OF GOD WILL HELP YOU TO LOVE GOD MORE AND MAKE gOD YOUR FRIEND

AS MANY AS I LOVE, I REBUKE AND CHASTEN, THEREFORE BE ZEALOUS AND REPENT. BEHOLD I STAND AT THE DOOR AND KNOCK. IF ANYONE HEAR MY VOICE AND OPENS THE DOOR. I WILL COM IN TO HIM AND DINE WITH HIM AND HE WITH ME. TO HIM WHO OVERCOMES I WILL GRANT TO SIT WITH ME ON MY THRONE, AS I ALSO OVERCAME AND SAT DOWN WITH MY FATHER ON HIS THRONE, HE WHO HAS AN EAR LET HIM HEAR WHAT THE SPIRIT SAYS TO THE CHURCHES.

TRANSFORMER CALCULATIONS

A single phase transformer has 5000 turns on the Primary winding and 1250  turns on the Secondary. Winding resistances are r(1) = 4 ohms and r(2) = 0.25 ohms. Leakage  reactances are x(1) = 16.0 ohms and x(2) = 1.0 ohms . The resistance load Z(2). If applied voltage at the terminals of the primary winding is 1200, find V(2) and the voltage regulation. Neglect magnetising current.

Let 'a' be turns ratio.

a = N(1) /N(2) = 5000/1250 = 4

R(1) = 4 + (0.25)(4)2 = 4+ (0.25*4*4) = 8 ohms
X(1) = 16 + (1)(4)2 = 16+ (1*4*4) = 32 ohms
Z'(2) = 24 (4)2   = 384 ohms



I(1) = 1200/(384 + 8 + j32)    =  1200/393.303954/- 4.6668
                                                      = 3.051075/-4.6668 



aV(2) = I(1)Z'(2)
            = 3.051075/-4.6668    *384  =1171.6129/-4.6668   
V(2)  =  aV(2)/a    =(1171.6129/-4.6668)/4    =  292.90323/-4.6668  


Voltage Regulation Is Given By


[{|V(1)/a| -|V(2)|}/|V(2)|  ] *100%

{(1200/4 ) - 292.9  }/292.9    *  100%


= 2.42% lagging

MORE QUESTION PAPERS

THESE QUESTION PAPERS WERE OBTAINED WITH THE EXPRESS PERMISSION OF THE LECTURER TEACHING THE COURSE FOR ACADEMIC PURPOSES.

ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT DEPARTMENT OF ELECTRICAL/ELECTRONICS ENGINEERING SECOND SEMESTER EXAMINATION 2011/2012 SESSION INTRODUCTION TO ELECTRICAL POWER SYSTEMS ENGINEERING. (EEE 352) TIME: 1Hr 30Min (Answer All Questions)

NB: IF you have not done any continuous assessment, write down what you have learnt in about 120 words first.

Basic Concepts

What is renewable energy sources? How does a transformer work? What is Load Duration curve? What factors affect the economic operation of Electrical Power Plants? Explain any two of these factors. How would you improve the thermodynamic efficiency of a Thermal Power Station? What is single line diagram? What is Per Unit System? Derive an expression for the efficiency of a transformer. How would determine the parameters of a transformer? Describe the relevant experiments and derive the relevant equations for this purpose. What is an autotransformer? How does it work and what can it be used for? Derive an equation for determining the winding impedances of a three winding transformer, using measurements from experimental values. Describe and explain your work. What types of lines are there in the Electrical Power System? Explain the differences between these types of lines. Derive a model and an expression for the medium line for Electrical Power System Analysis. What are line parameters? Explain any two of them.

Application

You are responsible for the establishment of a new Teaching Hospital in your state. What would you do to ensure that this hospital has steady Electrical Power supply? What would you do to ensure that if the hospital is located outside the town, support services provided by other utility services would be properly taken care of and that the Electrical Power needs of the entire medical complex and the host community is adequately met? Explain how your knowledge of this course would assist you in your work. What is Load Flow Analysis and what is it used for? What is fault Analysis and why is it carried out? What is Stability Studies and what types of Stability Studies are there? What is the relevance of State Estimation in Electric Power provision?

Calculations

A single phase transformer has 1000 turns on the primary winding and 200 turns on the secondary. Winding resistances are r1 = 1.0 Ω and r2 = 0.105 Ω Leakage reactances are x1 = 5.0 Ω and x2 = 0.25 Ω. The resistance load Z2 is 10 Ω. If applied voltage at the terminals of the primary winding is 1000V, find V2 and the voltage regulation. Neglect magnetizing Current. The results of the open-circuit and short circuit tests of a 220/110 V 10kVA single phase transformer are as follows Primary Secondary Open Circuit Test Open Circuit 100V , 5A, 154W Short Circuit Test 18V, 45.2A, 240W Short - Circuit Determine the parameters of the approximate equivalent circuit of the transformer and express these quantities in per unit values. The three phase rating of a three winding transformer are Primary Υ Connected 55kV 10MVA Secondary Υ Connected 12.1kV, 7MVA Tertiary Δ 2.2kV, 2.5MVA Neglecting resistance, leakage impedances are, Zps = 5% on 10MVA, 55kV base; Zpt = 8% on 10MVA, 55kV base; Zst = 7% on 7MVA, 12.1kV base Find the per Unit impedance of the star connected equivalent circuit for a base of 10MVA, 55kV in the primary. If N1 =1000 and N2=200 in a transformer. Draw the equivalent circuit of the transformer. If V1 = 1000/0o and I1 = 4/-45oA with impedance Z2 connected across the winding 2. Find V2, I2 and Z2 and the impedance Z’2 which is defined as the value of Z2 referred to the primary side of the transformer.

SOME WORDS OF WISDOM

WOE TO HIM THAT STRIVES WITH HIS MAKER. GOD MADE EVERYTHING FOR A PURPOSE. GOD IS THE FIRST AND THE LAST. GOD SAID FOR MY NAME SAKE I DEFER MY ANGER AND FOR MY PRAISE WILL I RESTRAIN IT FOR YOU; THAT I CUT YOU NOT OFF. BEHOLD I HAVE REFINED YOU BUT NOT WITH SILVER : I HAVE TESTED YOU IN THE FURNACE OF AFFLICTION. TAKE A LOOK AT THE BOOK OF ISAIAH 44, 48:9, 48:10-11, 45:8,9,10,45:17- CHILDREN OBEY YOUR PARENTS IN THE LORD LET EVERYTHING THAT HAS BREATH PRAISE THE LORD EVERY TREE THAT BEARETH FRUIT IS PRUNED THAT IT MAY BEAR MORE FRUIT. ANY TREE THAT BEARETH NOT FRUIT SHALL BE CUT DOWN. EPH 6:1-, JN15:2, JN15:2 Someone has written these beautiful words. It's a must read. Try to understand the deep meaning of it. 1] Prayer is not a "spare wheel" that you pull out when in trouble, but it is a "steering wheel" that directs the right path throughout the journey. 2] So why is a Car's WINDSHIELD so large & the Rear View Mirror so small? Because our PAST is not as important as our FUTURE. So, Look Ahead and Move on. 3] Friendship is like a BOOK. It takes a few minutes to burn, but it takes years to write. 4] All things in life are temporary. If going well, enjoy it, they will not last forever. If going wrong, don't worry, they can't last long either. 5] Old Friends are Gold! New Friends are Diamond! If you get a Diamond, don't forget the Gold! Because to hold a Diamond, you always need a Base of Gold! 6] Often when we lose hope and think this is the end, GOD smiles from above and says, "Relax, sweetheart, it's just a bend, not the end! 7] When GOD solves your problems, you have faith in HIS abilities; when GOD doesn't solve your problems HE has faith in your abilities. 8] A blind person asked St. Anthony: "Can there be anything worse than losing eye sight?" He replied: "Yes, losing your vision!" 9] When you pray for others, God listens to you and blesses them, and sometimes, when you are safe and happy, remember that someone has prayed for you. 10] WORRYING does not take away tomorrow's TROUBLES, it takes away today's PEACE.