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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