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  • Today in the lecture number 2, we will be primarily on Structure of Power Systems, now

  • all of you, are well aware what is power system. So, we have to slightly see in deeper in about

  • its structure. Before we do that, we left last time about the diversity factor I think

  • we have to come up to day light saving we have talked about it.

  • Now, staggering of the office timings, now what is staggering of office timing? Suppose,

  • some offices start 8, some 9, some 10, it does happen in our country all offices do

  • not start at 9'o clock. What is the advantage? The advantage is manifold for example, if

  • you know that your office starts at say 11, why should you take bath at 6 you will I know

  • get up leisurely take bath. What has bath to do with your energy, because

  • you will start your geyser, so you are using energy at different times; hence diversity

  • factor will be help. Everybody in Delhi is not going to start his geyser or her geyser

  • at a same time. So, as I said for every activity that you do, you need electric energy, preparing

  • breakfast you need you know the toast or sandwich maker or mixie or microwave or whatever? So,

  • all these activities will take place at different times, because you have to get out of your

  • house at different times. Incidentally the bonus is ease of transportation

  • system. Imagine, if whole 1 crore leaves their houses at same time, do you have that transportation

  • system in place, the buses, you will not find any space, and there is no railway network

  • as yet. So, it helps to ease the transportation problem at least you will get a space to stand

  • in a bus; or even if you are taking your car out, you know there may not be a jam.

  • Different time zones, now what do you mean by different time zones? India is the country,

  • where there is only Indian standard time right from Kanyakumari it will Jammu and your Somnath

  • to Assam. But, please understand before partition, even Peshawar time was same as time as Delhi

  • time. Now, Pakistan is half an hour behind and Bangladesh is half an hour ahead I hope

  • all of you know this fact. So, why not we divide the remaining part of

  • the country what is India today into three parts. Let the western zone we have Pakistan

  • timing, let the eastern zone have the Bangladesh timing, and the central zone today's Indian

  • standard time; you may ask me questions, so what we happen, there may be more confusion,

  • well confusion would not be there, because people will be understand.

  • Now, the bus is going to Lahore they suddenly adjust their clocks, moment the reach Lahore

  • border. So, you will be adjusting your clock, moment you reach Ambala let us say the Ambala

  • time zone changes. But, what is the advantage? The advantage is instead of having 1 peak,

  • now you will have 3 peaks and smaller ones. So, you need not un necessarily have higher

  • install capacity you can do away with that, you need not add any extra capacity and whatever

  • capacity you have, that can be used more optimally. Because as you all know adding a mega watt

  • needs 4 crores, transmitting that mega watt needs another 4 crores that is today's price.

  • And where are crores in India, we do not we are a poor country we do not have money.

  • So, in order to avoid that capital investment, which government does not have; because by

  • enlarge, most of the power systems in India is being controlled by government of India,

  • there is hardly any private participation. Though, we desire we hope we request them

  • please come in and invest money. But, you know the Indian power system privatization

  • started and ended with Enron, Enron he was a sad story like your Devdass. So, people

  • do not want to repeat another Enron. So, it is a basically the duty of the government

  • to provide you power and they do not have money. So, why not use the existing power

  • system optimally and there, these different time zones will definitely help us. And mind

  • it as I said in the last lecture, all these measures do not need any money, they are free.

  • If you declare tomorrow will timings will change as you pass Ambala or Kanpur, you do

  • not have to pay anything, only thing you have to adjust your watches; as indeed you will

  • go do it when you abroad, when you go to US you adjust your watches to New York time's,

  • Delhi time would not be there. Then, the last item in this category of high

  • diversity factor is a two part tariff. What is tariff, when you go to hotel you ask what

  • is a tariff what, how much it will cost you if you stay for night. So, similarly, the

  • power you get in your home or industry or a commercial building, you to pay nothing

  • is free. So, there is certain tariff and in India the most popular tariff is two part

  • tariff. And two part tariff means, what? There is a charge for kilowatt there is charge for

  • kilowatt hour as we will see after some time the equation exact equation.

  • You should have an incentive to have better power factor, why better power factor? If

  • power factor is low, the P is equal VI cosine phi all of you know this equation, now power

  • factor is low voltage being constant, the current will go up to get the same value of

  • P this which mathematics everybody knows. Current going up is not good, it is bad. Why

  • it is bad? It will have more more losses I square r your conductor will get heat up,

  • your insulation may melt it may fail. So, our aim should be to have as much higher power

  • factor as possible. So, that is a part of power quality I am sure all of you must have

  • learnt a topic called power quality, now it is very important topic in under graduate

  • wherever you have done done your that the degree.

  • So, if power factor is high we say power quality is good. Another power quality issue is harmonics,

  • which you must have heard about T H D Total you know Harmonic Distortion, which should

  • be less than 5 percent; if you have done power electronics course or drives course in your

  • under graduate. Then I have two more factors given on this sheet, plant capacity factor,

  • plant use factor.

  • Now, these two factors are equally important as were the earlier two, the load factor and

  • diversity factor. What does the plant capacity factor convey its nothing but, a ratio any

  • factor is got to be a ratio, ratio of actual energy produced upon maximum possible energy

  • that could have been produced. In fact, you also have a study factor, the actual studies

  • carried out by you up on what you could have really done.

  • So, you should also try to use this factor in order to have better studies schedule or

  • program. This is in short can be written as a average demand up on installed capacity.

  • What is the use, if you have better plant capacity factor that means the existing plant

  • you are using optimally, you are using in a better way. See, you purchase a book 400

  • rupees and if you do not open it through out the semester, you have wasted your 400 rupees

  • if you get a scholarship; otherwise, you have wasted your 400 rupees of your parents or

  • whose ever is supporting you. Next is plant use factor, look the difference

  • between the two factors they are not otherwise, I would not have written them twice. Plant

  • use factor is nothing but, actual energy produced kilowatt hour upon plant capacity into time

  • the plant has been in operation. This is a maximum possible energy, here actually what

  • energy you could have generated, if you have used plant capacity. So, indirectly maintenance

  • is involved in it, indirectly how you are up keeping your power plant is your whole

  • plant capacity available or there is a d rated. What is rated? 100 mega watt unit in never

  • operated in 100 mega watt in India, it is rated to 80 mega watt; like, you people do

  • not do your work to the best of your capability you always do less than that, that is a rating

  • of yourself.

  • I was just talking about tariffs couple of minutes back the tariffs is back here, cost

  • of electric power nothing is free, there is no free as they say in management. So, if

  • you take a power otherwise it will be called theft, those of the person who use electricity

  • without paying that is nothing but, a power theft.

  • In fact, in our country, theft is one of the highest 40 percent of the power is you know

  • used are not paid for; and that is why T N D the part of your title of your course is

  • renamed as theft and dacoity, not transmission and distribution, which is very unfortunate.

  • And every person is trying to reduce this theft, power theft.

  • Now, the cost of electric power is given by a plus b kilowatt plus c kilowatt hour, what

  • are a b c, this three are coefficients all of you have done enough mathematics to understand,

  • what is coefficient; a is constant is a fixed charge like, telephone whether you make a

  • single call or not, you have to pay that 250 rupees rent. And that is why people are going

  • more and more for mobile phone, because there is no rent there, if it is a prepaid, they

  • already cut whatever they want to cut. Plus b time's kilowatt, b is proportional to maximum

  • demand, as c is the units actually consumed. So, all of you must be paying electricity

  • bill or your parents must be paying electricity bill at home. So, that bill will give you

  • one is a fixed charge then depending on what is your connected load in your house; when

  • you get connection, you have to declare what is your connected load, and then the actual

  • energy consumed, which energy meter shows. Unfortunately in this country, all auto taxi

  • meters are fast all energy meters are slow. In fact, some of the energy meters run in

  • opposite direction in night. So, that by the time morning is there, you are back to the

  • starting point. Now, this should influence the load curve and load factor. Now, if load

  • factor is low, there should be penalty on the consumer. How do you...? By replacing

  • kilowatt to K V A; what is k v a kilowatt into cosine 5 power factor. So, rather having

  • a kilowatt, let us have k v a and then, the consumer will be careful in having a better

  • power, you will be forced to have a better power factor.

  • So, he has to install power factor corrective devises, this is what people do in energy

  • audit, I am sure you must be doing that energy audit course. Have you are you doing there,

  • evening people have a compulsory 1 unit energy audit course; and I request you to go and

  • sit there. Because, there are some courses which are not there for the morning students

  • which is bad? So, you can go and nobody will say no, everybody

  • is welcome please do that energy audit course. What is energy audit, you have to go and see

  • in any any premises whether it is a factory, whether it is a building, whether it is a

  • restaurant; how the energy is being consumed, in what energy is being consumed; is it being

  • consumed rightly, is the bulb not required 100 watt in 50 watt will do, is it being even

  • the house keeping measles to improve. Then you know the energy c is to keep your

  • things clean you do not have to wait for Diwali to clean your bulb. It can be cleaned regularly

  • and will find the difference the lumens coming out will be much more than normally you get.

  • So, this is what we do. You have to see the why voltage is coming down, why not we have

  • a voltage stabilizer, the power factor. How do you improve power factor, just by putting

  • capacitances in shunt with load, the power factor will be go up. No doubt, there is a

  • cost further capacity, there is a price to pay, but it is worth; because there is a something

  • called payback period, you invest 10 rupees and that 10 rupees you will realized back

  • in no time; and the payback period will be few days or months or at the most a year,

  • it is worth. Other things are S V S etcetera Static Var System. fax I do not know how many

  • of you know FACTS Flexible AC Transmission System. So, all these things are come here

  • to have three in one. They not only improve power factor, they improve

  • efficiency and they improve the voltage control, voltage stability is you know achieved. What

  • is the optimization problem here, what is problem here, what is the problem here, compensation

  • how much where when, if you answer these three that is your R and D topic.

  • Now, there are five examples solved in the book 1.1 to 1.5, please go through these five

  • examples. If you have any difficulty in understanding them, if necessary we will have a separate

  • class for this, if not, because they are solved. you should how do you read a solved example,

  • how do you solve a solved example, that is also an art; do not read it like a novel or

  • a magazine, read the problem close the book try to solve it yourself, because we have

  • already covered a theory. The beauty is why do you why should you solve

  • the solved this problems, you know exactly where you have gone wrong; in an unsolved

  • problem, you would not be able to know where you have gone wrong, only thing you come to

  • know is the answer is wrong. But, why answer is wrong it is not so easy to find out, you

  • have to consult your colleague who should be solving it independently. And if you do

  • that same mistake, again there is a problem you never come to know where you have gone

  • wrong. So, the solved examples of very important,

  • please go through them solve them yourself independently; and let me know whether you

  • you have solved them or was the is there any difficulty you please let me know. What is

  • load forecasting, it is a very important topic today. You must be seeing weather forecast

  • every day whatever channel you may tune for I do not whether present day students at all

  • see anything other than m TV and v TV. But, if you care to see any news channel, then

  • there will be a weather forecast, even Doordarshan also shows 4 megacity temperatures, now a

  • day they have started giving other city temperatures also.

  • Now, any planning will need this load forecast, you are planning a power system for 15 years

  • hence, for the India of 2020 what should we know? We should know several factors, what

  • we will be the population, what what will be the industrial scene, how much agriculture

  • will be there, how much houses will use electricity. Today only 85 percent villagers have been

  • 15 percent are not. And these 15 percent are places in accessible places hilly areas, there

  • is no grid there. So, are we able to take grid up to that point or not, we have to plan

  • all these things. Power plants, once you know the load, then only you will go for power

  • plant. How what do you do when you go for a market; suppose, your mother or father tells

  • I will get you a shirt then you decide in your mind up to 500 rupees, then they take

  • 1000 rupees in the packet and go. Of course now a days, there are debit card and credit

  • card that is a separate story. So, you have to plan what you want to spend, before going

  • to the market. So, you are planning every time every day,

  • right from getting up in the morning to sleepy. In fact, when you sleep, you must ask question

  • to yourself, how was the day, was it past meaningfully or you have just wasted it. So,

  • that next day should not be this same, that should be the you know aim of life.

  • So, once you know the load coming in 2020, then you can prepare for that load by planning

  • power plants, because load is increasing exponentially, population is increasing exponentially in

  • India. So, why should you have to plan power plant, there is something called gestation

  • period. What is the gestation period? The total period required before a project is

  • completed; where M Tech course gestation period is 2 years, Ph D gestation period is normally

  • 3 to 4 years, it all depends on you. Even in M Tech, your thesis is not complete it

  • goes beyond 2 years. So, a thermal power plant need 4 to 8 years,

  • a hydro plant in India needs 10 years, a nuclear power plant needs 4 to 5 years. So, before

  • you want to have a power plant, you have to start working finding capital looking for

  • a fuel whether you have that much coal with you or water with you; building a dam, you

  • must plan in advance, for that you need to know load, whether load is going to come or

  • not, how do you know. Energy and load forecasting plays a very crucial

  • role. If your 5 years plans which the country makes a big role is played by this, the load

  • forecasting and energy. Because, whatever you do, you need energy; all this computers

  • will stop, if you do not have how much UPS you will use, and how long you will use. Even,

  • this inverter so inverters which you use in houses, they cannot give you power for 12

  • hours, 18 hours, 24 hours, so they are only for short time.

  • How how many you know zones are there for planning? There is a long range, middle range,

  • short term, very short term. And now like you must be planning for very short term,

  • next 1 hour what you do after the class is over, then you plan for middle term the whole

  • week, then you plan for again for the rest of the year, and then rest of the carrier

  • very long term.

  • There are sophisticated probabilistic methods given in the literature. In fact, there are

  • books written just on load forecasting and if you have time if you are free, you can

  • go through the books, there are references given at the end of each chapter in the book;

  • I do not know how much time you have, that you have to plan again.

  • Simple extrapolation technique is good enough for long range planning. For example, you

  • have data up to 2003 august let us say. Now, if you want a data for 2004, what you do?

  • Collect the data for 20 years plot a curve I am sure you must have read curve fitting

  • techniques in your numerical analysis course; if you have not done the numerical analysis

  • course, you can always read a by book by Hildebrand , , and so on, there are so many numerical

  • analysis books. Extrapolation technique is very easy you must

  • be doing extrapolation when you have done your labs in your under graduate, open circuit

  • test, short circuit test; especially if it is a straight line like short circuit test,

  • you take three points and then you join in straight and that is extrapolation.

  • Weather normally affects a domestic load, and industrial load would not be affected

  • that much by weather, whether it is running out side, whether there is a storm or snow

  • storm; inside, if you are running a lath, lath is a being run. But, domestic load gets

  • affected as it is small load of course, sigma is big, but individual house is a small load

  • 3 kilowatt, 5 kilowatt depending on how rich you are, how many A C's you have fitted in

  • your rooms. So, the weather forecast is very important

  • and the domestic load is sensitive to that. I am sure, you must have done sensitivity

  • studies in so many courses in your curricular, how much sensitive, some people are more sensitive

  • than others you know. So, why not forecast load in a constituent form totality; and then

  • add it, forecast domestic load, forecast agriculture load, forecast commercial load, forecast industrial

  • load and add them, that is much easier and much better and more accurate, rather than

  • forecasting the total load in one go. There are multi factors which affect forecasting.

  • So, it is an involved process, it is not an easy process, there is whole department in

  • planning commission dealing with forecasting. What is important experience, why do they

  • ask for experience for a particular post, 5 years of industrial oblique, teaching oblique,

  • R and D experience? Why why do they ask, because they know the experience person is better

  • than a raw person; if he is a raw person people will give him job or her job, but at a lower

  • scale, lower grade, lower post, lecturer, assistance professor, associate professor

  • and professor. And analytical ability should also be seen whether we can analyze things

  • or not.

  • Short term is hour by hour predictions for the day I did mention you about the load dispatch

  • centers in Katwaria Sarai do you remember? And I told you to go to your teacher or M

  • Tech coordinator or head to arrange a visit there for all of you whole class not just

  • this subset, because all of you are studying energy. There, they are doing this hour to

  • hour prediction if it is now 11:31 what will be loaded 12, what will be loaded 1 pm. So,

  • that there is a mid course correction, online monitoring and control, real time monitoring

  • and control. Every minute you have to monitor this system

  • you know what is ICU, there the monitoring is every in 5 minutes, every 10 minutes that

  • is ICU Intensive Care Unit, you are taking intensive care. If you have a minor error

  • in your forecast, what will happen? You will have to use minor error in negative direction;

  • that means instead of predicting 25 mega watt which is the correct value which will be coming

  • at 12, you have predicted 20 by mistake; or may be a wrong model, may be a wrong input,

  • output depends on input. If you do not work, how do you get a grade.

  • So, instead of 20 mega watt you have predicted you have got 25 mega watts, what will happen?

  • You have to immediately start peeking unit which are inefficient and costly; all peeking

  • units are costly, that is why they are called peeking unit, which is not normally used.

  • Wherever you have to go alone for some small job you take a scooter you do not carry your

  • car or take your car, why? Car is costlier maneuver it, you cannot maneuver it on Delhi

  • roads or Indian roads, it is easy to maneuver scooter; if scooter fellow can come right

  • up to the red light, a car cannot do that, standing where he is standing.

  • So, you have to start inefficient and costly units if you have gone wrong in your forecast.

  • Suppose, you have gone wrong on a higher side, you have predicted 30 mega watts, but actual

  • load which comes is 25 mega watt, then what happens? Unnecessarily, you have planned for

  • 30 mega watt excessive generation in hot reserve which you do not need. It is like that, you

  • need 5 rupees and you are taken 500 rupee note in the market, why it may be pocketing;

  • you may get or tempted to purchase something which you are not originally planned. But,

  • you have taken 10 rupees and no card with you, you will come back you will not purchase

  • that extra shirt, if you go to plaza or wherever. So, accuracy of 1 percent is desirable. A

  • temperature difference of 2 degree centigrade can vary total load by 1 percent, how? This

  • point needs bit elaboration, suppose the weather forecast tomorrow 6th of August tomorrow,

  • you say it will be 28 degree centigrade or let us say, 30 degree centigrade, though it

  • is going to be 28 actual, but you have predicted 30. Now, 30 degree centigrade people start

  • using fans. So, then you have calculated the how many fans will be use in Delhi, how many

  • coolers will be used in Delhi, how many A C's will be started. But, if the temperature

  • is 28 only which is quite ok, you at least do not need A C, you at least do not need

  • cooler, may be fan with if it is free, office if somebody else is paying.

  • So, you know number let the fan be on, how does it matters, somebody else is paying.

  • But, if it is 15 degree even if somebody has his paying, he would not keep your fan on.

  • So, a difference of 2 degree centigrade can matter a lot at in such situation, where it

  • can make lot of difference in making a decision whether the fan should be on or off. Look

  • at the load how much change will be there in load forecast, just because your temperature,

  • there was the error of 2 degree centigrade; think of the reverse, you plan for 30 degree

  • it became 32 or 35; practically even will start his fan 35 degree centigrade, so again

  • you have gone wrong. So, a temperature difference of 2 degree centigrade

  • can vary total load a 1 percent, so there is a need of reliable weather forecast; you

  • cannot do a second job second grade job, you have to do a first grade job in exactly predicting

  • of course with in that error of 1 percent. But, what is the problem, you are not a god

  • after all you are a human being, even your software you are developed, it was also developed

  • by human being, they are not been send by heaven hey take this software it will work,

  • it may not work. What are the random factors which affect your

  • performance? Un expected storm otherwise, why anybody should die, if you can predict

  • accurately that tomorrow there will be a railway accident nobody will go in that train. If

  • you can predict there will be highjack of this plane do you think even the will go,

  • everybody will apply for a casual leave or sudden sickness leave; unfortunately we do

  • not know in advance many things in life. If all those people who got divorce, do you

  • think they were knowing when they got married, will be divorce otherwise, they would not

  • have married. So, that is the life name of uncertainty. And hence, strikes you know the

  • just few days back, British airways had a lighting strike on Heathrow airport thousands

  • of passengers were they had to sleep on the floor, they were not having any dollars in

  • their pockets; because, they were going to their near and dear ones in U S thinking that

  • they will take care, they have purchased ticket anyway and the air gives you free food, free

  • drinks, everything free. So, they are not prepared for this eventuality that there will

  • be a sudden strike by British airways personnel and so all flights will be cancelled. It took

  • them 24 to 48 hours to put them into alternative flights, because alternative flights are not

  • really available, there are already booked. A good TV program you are not planned for

  • it, the talks are going on for live telecast you are not sure whether tomorrow the world

  • cup or whatever foot ball, cricket will be telecast or not; there is bit of controversy

  • on sponsorship or whatever you know the controversy of last world cup and suddenly they say, there

  • is a telecast available. So, everybody's is to his TV set. And who

  • will plan for such so many TV set's on, you are not planned for it, so there will be problem.

  • Same thing happened in 1982 when Prince Charles marriage with lady Diana who is no more was

  • telecast throughout the world; and imagine how much power they must have planned extra

  • power.

  • Regression analysis is another technique by which you can have a short term load forecast,

  • why do you want short term load forecasting? There are problems called unit commitment

  • and economic dispatch; I do know how many of you know what is unit commitment will be

  • doing it in a next course in energy called power system planning ES 8 6 0, if I take

  • or anybody takes he or she will be teaching UC and ED.

  • Unit commitment is which unit should be on or off, when a particular load comes tomorrow,

  • some of you might have studied in you under graduate. It is given in our book in chapter

  • 7 in case, those of you are not studied they can go through that chapter. Economic dispatch

  • is how much units will share the load? So, that the total cost is minimum; say, 100 mega

  • watt load is coming, should it be 50 50, 70 30, 80 20, 10 90, 0 100, 100 0 these are various

  • possible combinations. ED software will tell you how much each units

  • should carry, how much units will be on or off; UC having made them on, how how they

  • should share the load belongs to problem of ED. Now, both this problem need load, if load

  • is not there; so, if bride and bride groom are not there, no marriage. So, if load is

  • not there, no power system. So, you have to forecast the load.

  • So, that you can find out the solution to any power system problem, whether it is a

  • faults studies, stability studies, security studies, reliability studies, economic dispatch,

  • load flow, unit commitment name a problem; every problem need a input called load if

  • load is not there. Any job you go you ask sir what package will be there, how much I

  • will get; when when they will say any question stand up and lady sir how much will be my

  • package how much I will get can you not give me one more increment something like that.

  • Demand is increasing exponentially I have repeating this, this is the main problem.

  • Total generation installed capacity today in the country has crossed 100,000 mega watt

  • in 2000 ; the 100 th 100 100 crore baby was also born in 2000 in the hospital. And 101

  • this what you call as 100,000 mega watt 1 lakh we say, lakh and crores in outside world,

  • they recognize only thousands, millions, billions, trillions.

  • You know when we started our journey what was our installed capacity in 47 when India

  • got free India became free India got freedom just 1360 mega watt, 1360 mega watt; imagine

  • from Peshawar to and Srinagar to Kanyakumari big country, 33 crore was the population one-third

  • of today's population. The the installed capacity was just 1360 mega watt, I remember in my

  • town we have all use to study using kerosene lamp, candles and so on, used to study use

  • no electricity. He is very prosperous person, he is a very

  • wealthy person. What use to be for TV in 70's, people use to come to your house; can I come

  • and have a Chitra? Sure, please come. So, he is to be very grateful to him, when used

  • to give you opportunity to watch it, may be you are not born in 70's. Same thing happened

  • to cable in 80's. Now, cable is there in every house hold, even, this is how things change

  • time change. Today, 1360 mega watt has become more than

  • a lakh; yet, there are shortages, why? It is a story of a person who wanted to purchase

  • ambassador in 1960, when ambassador is to cost 20,000 he was having only 15000, today

  • it is 3 lakh he is still having only 2 lakh. So, the moral of the story is he could not

  • purchase anything. So, we are improving non installed capacity, yet the total load is

  • going faster and hence, what is happening? Every day we will have blackouts, brownouts,

  • shortages. In fact, if any day power does not go, we

  • feel miserable something wrong today, why power is not gone, so we will so much use

  • to it. 2020 estimate is this is going to be double that means whatever installed capacity

  • added, from that 1886 to today 2003, same thing you have to add in another 15 years;

  • task, not easy you need man power, you need money, you need development of infrastructure,

  • it will build dams, you have to build thermal power plants. So, tremendous task, you need

  • resources, you need man power. Today, 2003 is 100,000 mega watts, thermal

  • is 72 percent. Thermal means oil gas coal largely coal in our country. Hydro is 24 percent,

  • nuclear is 3 percent and then, renewable is 1 percent I hope the total is 100 you can

  • just check. Hydro for the first time as gone below 25 percent, it use to be 50 50 in 60's

  • when I was a student, 50 percent thermal, 50 percent hydro, thanks to buckram. Nehru

  • called them modern temples, d v b eastern India so on, there was several hydro power

  • plants in the country. The first hydro power plant was build in Darjeeling

  • 1898 followed by river in Bangalore same year, the capacity was 30 30 mega watt lot of water

  • is fallen and . But, why this is going down and down, because of several reasons, 10 years;

  • gestation period I told you, who can plan for 10 years when he do not know whether you

  • are you have a stable government likely this government has been stable, but then how stable

  • how much stable like; not like earlier days government when you have your own 300 MPS,

  • it is totally dependent on so many factors and experiment.

  • So, where is a time to plan, every day you are answering for something, some issue, some

  • this issue that issue, where are developmental issues. So, there is no money, there is no

  • planning and thirdly, the the reason is equalogical and environmental issues. There are persons

  • called Baba Amte, there all in strike whenever they want to reduce their weight they sit

  • on strikes under strike; and that is why the hydro power plant is going on for last 15

  • years. And the Narmada dam height they are not able

  • to decide even after 10 years. What should be the height, do not you think it should

  • have been decided before you start building the dam. It is like a analogy I can give you,

  • you are invited a family for dinner after they arrived you form a committee what should

  • be the menu, should be parota or a rotti or puri, why cannot you form this committee one

  • day in advance in come to some conclusion not after the guests arrived.

  • So, in Narmada dam height should have been debated in public before you started planning

  • for let or whatever it is well. The nuclear is also not going much ahead, because it is

  • also in the world. Certain countries you cannot even pronounce the nuclear like it is Germany,

  • if you do that they will put you back in the flight to India, because there are problems

  • I told you the 3 mile island; and what you to do the nuclear etcetera etcetera.

  • But mind it, there countries called France, Canada. In France, two-third of the power

  • is generated by nuclear, no no 3 mile island; you do not take care you take precautions,

  • people die on roads, have you stop walking on roads; there are car accidents, have you

  • stop using cars; there are plain highjack's, plane crashes, . Do you get ticket for Bombay

  • today in spite of 10 flights a day, no. So, what you have to do is, you have to take

  • the precautions we have be careful when you operate a nuclear power plant. The the answer

  • is not close nuclear power, if you have a thorium largest deposit as I said 45000 tons,

  • why do not you use it, it is your valuable resource. Renewable of course, the whole course,

  • whole M tech is on renewable, so there are so many and experts in that building block

  • 5 who will be talking in room number 344 on renewable. So, I will not talk much on that.

  • Structure of power systems we have come which was actually the topic of the day. State electricity

  • board, all of you must be in some state and your state has a realistic board, there is

  • a regional grid, there are 5 regional grids in the country.

  • This is the map of our country N R E B, W R E B western zone western region, S R E B

  • Southern Electricity Regional Grid or Board. Eastern region and north east is being having

  • special importance we have north east those states you know Arunachal Pradesh, Nagaland

  • and so on. Why they are divided their country into 5 regions, so that at least they can

  • be interconnected, and they can come to rescue of each other in case of demand.

  • So, each state electricity boards are interconnected n fact, this regions are also loosely interconnected.

  • As I told you on very first day, HVDC line is connecting from Assam to South, so this

  • is having a extra power and this extra power can be evacuated using HVDC link to the South.

  • Now, we want to have a national grid. What is national grid, when this 5 regional grids

  • will be strongly interconnected that will be a national grid.

  • Since 80 we are hearing that national grid will be soon in place, how soon it will be

  • there I am not able to tell you, but one day yes and on that day, theoretically we should

  • be able to transmit power from lake to Kanyakumari or to Assam Guwahati. In fact, we to have

  • a grid, I am sure you know what is , our neighboring countries Bhutan, Nepal, Pakistan, Srilanka,

  • Bangladesh; we have a connection Bangladesh, Pakistan was about to give us 2000 mega watt

  • and the kargil happened, so we never got that. Nepal we do have some power plants build by

  • us, and in return they do give us power. So, we do have a grid.

  • Whole of Europe is the international grid, the countries are like our like our states

  • in fact, the Europe has really become 1 when the currency is 1, the parliament is 1, everything

  • is 1; be our countries, south East Asia.

  • International grid, national grid, why should we have a grid, it is economical. If two of

  • you purchase a book well, unless until tomorrow is and then there is a fight who should read

  • first, unless until there are more than one books, but it is economical; or you have a

  • common car 4 of you can go together. Technological reasons, it helps you; siting of a power plant

  • is very important, there are technical, economical, environmental, and political factors, what

  • is technical. You should have a coal available there you

  • should have water available there. The siting is more flexible for nuclear, because of fuel

  • required is very little few kilo grams you can carry in your bag; not so coal, coal you

  • have to transmit in . Power, the hydro is least flexible site selection, it will go

  • where the water is, you to build dam there only. I already explained you thermal coal

  • based and load based; interconnection, all these power system is interconnected, because

  • you can get power from area to area, area to area depending on the time.

  • What are the advantages of interconnection? You are just talking about that, reduction

  • in reserved generating capacity; each system did not have a reserve, because there is a

  • common reserve, so you are saving money. Why, we go for the company goes for the same cars,

  • Ford Hyundai or Ford Maruti. So, that you can keep common reserves, the minimum reserves

  • or spare parts whatever you want to call it. Borrow power from adjoining area. Capacity

  • saving from time zones, time zone is not same in one region. So, as I explained you that,

  • peak will come a different time; in north in winter all employees you know eat their

  • lunch hour, lunch hour will be separated now; when it will be 1 clock for him, it will be

  • 12:30 there. So, by the time, his lunch is over he will start. So, time zone will help

  • you in capacity saving. Facilitates transmission of off-peak power,

  • some where it is off-peak some where it is peak you can transmit power from one end to

  • another. Flexibility to meet unexpected emergency loads; if there is suddenly some load comes

  • up in some region part of the region you can rush the power from another region. So, these

  • are the advantages of having interconnected power systems.

  • Now, this is the power systems structure, this is generation, this is transmission,

  • this is sub transmission, this is distribution that is the name of our course; generation,

  • transmission and distribution of electric power. Generating stations always generate

  • the voltage 11 kV to 25 kV. Now, some one of you can ask me question why

  • not generated 400 kV, no need of transmission? We cannot, all of you have studied machines

  • course in under graduate; there is problem of , is a problem of insulation, is a problem

  • of material, you can go at most up to 25 kV. And hence, you need a transformer to step

  • up the voltage, why? The transmission is cheaper at higher voltage.

  • In the fact, the bulk transmission is possible only when the voltage is higher. Because,

  • it power transmission is proportional to V square. I told you that the other day, e v

  • x into sine delta, delta is fixed 15 to 30 degrees for stability region, excess field

  • fixed, once the transmission line is built and e and v are constant. So, they are equal.

  • Assuming that, voltage drop is not much, voltage regulation is very good.

  • Higher the voltage, more power you will able to transmit. So, we cannot have transmission

  • at a lower voltage, it has to be higher and higher; you have reached 400 kV level soon

  • we want to be 765 or 800 kV. Then this sub transmission 33 kV 138 kV there are large

  • consumers, you can have a generator here also to have an extra power fed into network, then

  • again there is a transformer step down. Now, it would do not need any more is 400 kv, because

  • we have reached the distribution level, because the action is only at a lower voltage, all

  • loads need lower voltage. So, the distribution level medium large consumers

  • an 11 kV and a small consumers three phase 440, single phase 230 volts. So, this is the

  • ladies and a gentleman is our class for today. And tomorrow we will continue with the same

  • topic that is the structure and conventional power plants, that is what we are going to

  • do tomorrow.

  • The next lecture is in thermal power stations, we have done diversity factor, load forecasting,

  • interconnection and of course, power system structure. Any questions, any queries no yeah.

  • Higher the voltage lower the losses, because the current will go down; V I cosine pi as

  • I told you, if V goes up, current comes down. Lower the current squared losses will be lowered,

  • the conductor size will come down, the cost will come down; and there are better compensating

  • devices to control voltage at higher voltage; facts in under graduate. That is right static.

  • Well HVDC transmission itself is a separate topic a books are written there. And naturally,

  • whatever are there in ac system will be missing in dc system, but do not think it is perfect

  • otherwise the whole ac transmission would have been substituted by dc transmission.

  • There are problems, what are the problems? You need inverter and converter, a rectifier

  • stations that means power electronics; once power electronics comes, harmonics comes of

  • course, they are becoming cheaper and cheaper like your computers.

  • But, there are other limitations there is a, what distance, there is an ideal distance

  • beyond below which it is not cheaper. In any case, we are going to have few lectures on

  • HVDC transmission, so at that time perhaps you will be able to know more about it, not

  • today. Today is that is this much is enough, but we do have a HVDC and there will be co

  • existence we need ac, as well as HVDC. And HVDC will continue to be a small percentage

  • of ac, because you cannot just throw like what we did in computer you cannot do in power

  • system, there you can go on 286, 386, 486, Pentium I upgrading; you cannot it is there

  • it is a reality, you have to use it as long as it gives you power. Yeah any other question

  • please, if no thank you very much.

Today in the lecture number 2, we will be primarily on Structure of Power Systems, now

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B1 中級

講座 - 2 電力系統的結構 (Lecture - 2 Structure of Power Systems)

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    iepavb 發佈於 2021 年 01 月 14 日
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