Introduction to Power Engineering[EEE281] Mushtaq Ahmad Bhatti Principal Engineer Department of Electrical Engineering COMSATS Institute of Information Technology, Wah Cantt, Pakistan
My Background • M.S Electical Engineering • Control Systems • University of Michigan, Ann Arbor USA • Master of Telecommunication Management • Institut National Des Telecommunication France • BSc Electrical Engg • University of Engineering and Technology, Lahore • Received Science &Technology Scholarship by Government of Pakistan for higher studies in USA. • Secured first class, second position in B.E with HONOURS. • Obtained SILVER MEDAL & CASH PRIZE on securing first class 2nd Position in F.Sc. from Multan Boardwith A-1 grade. • Obtained SILVER MEDAL &CASH PRIZES in matriculation exam. • Merit scholarships throughout academic career.
My Background • Management experience in the capacity of MP-II (Director Telecom, MoIT) and MP-I( Member Telecom, MoIT) • Chief Executive Officer of Public and Private Entities • Conceptualized USF Policy Framework and designed first lot for auction • Served as USF Board Member • Auction of Cellular, WLL and LL Licenses • Policy Formulation Experience for Telecom Sector • De-regulation Implementation experience
My Background • Regulatory Compliance experience • Privatization experience of Incumbent Operator • Experience as Board of Director of eminent Telecom entities • PSDP project Development experience for Telecom sector
My Background • Represented Pakistan internationally on renowned forums of ITU, ATP and CTO • Enlisted as Certified Director with Pakistan Institute of Corporate Governance after Certification in Corporate Governance Leadership Skills Programme • Trio experience of working with Incumbent Operator, Regulator and Policy Formulation body
Recommended Books • Principles of Power Systems by V.K. Mehta, Rohit Mehta • A course in Electrical Power by J.B. Gupta • Electric Power System Basics by Steve Blume, latest edition • Guide to Electric Power Generation
Course Objectives • Give understanding of Electric Power Systems fundamental • Basic Electrical terminology and concepts of • Power Plants • Substations • Transmission lines • Distribution lines • Basic electrical safety concepts
Course Outline # 1 • Fundamentals of Electric Power • Conversions of natural resources into electrical energy • Generation • Brief introduction of different types of power plants • Transmission • Requirement and types of transmission lines • Distribution Systems • Brief introduction of different types of distributions systems • Utilization • Different types of loads
Course Outline # 2 • Power Systems Protections • Concepts of Power Systems Protective Relaying • Power System Operations • Interconnection and Regulations • Benefits • Regulatory Requirements
Fundamentals of Electric Power • Energy basic necessity of life • Energy has made • shorter working days • Higher agricultural production • Higher industrial production • More balanced diet • Better transportation facilities • Energy used per person and standard of living are corelated
Fundamentals of Electric Power • Importance of Electrical Energy • Energy exists in different forms but most important form is Electrical Energy. • Energy may be needed as heat, light and motive power • Due to technological advancement electricity can be conveniently converted into other forms • Advancement of country measured in terms of per capita consumption of electrical energy
Fundamentals of Electric Power • Convenient form • Easy control • Greater Flexibility: Ease of transportation from one place to other • Cheapness • Cleanliness: not associated with smoke, fumes or poisonous gases • High Transmission Efficiency
Generation of Electrical Energy • Conversion of energy available in different forms in nature into electrical energy is known as generation of electrical energy • Electrical energy is manufactured commodity like furniture, clothing • Unique characteristic: Instantaneous production and utilization
Generation of Electrical Energy R Y B Energy from some source Alternator Prime Mover
Sources of Energy • Sun • Heat energy radiated by Sun focused with the help of reflectors • Heat energy used to raise steam which in turn runs turbine-alternator • Requires large areas • Not useable in cloudy days • Uneconomical method
Sources of Energy • Wind • Wind mills drives generators • Generators charge batteries to be used when there is no wind • Maintenance and generation costs are low • Variable output • Unreliable • Power generated is small
Sources of Energy • Water • Potential Energy • Turbines • Alternators • Popular because maintenance and production costs are small • Fuels • Coal • Oil • Gas
Sources of Energy • Nuclear Energy • Fission reaction of Uranium releases abundant amount of heat • 1Kg of Uranium produces equivalent to4500 tonnes of coal • Heat……>steam…..>Steam turbine……>Alternator • High Cost of fuel • High cost of technology • Problem of disposable radio active material • Dearth of trained personnel
Sources of Energy • Comparison
Ball park operating Costs Nuclear: $10/MWh Coal: $40/MWh Wind: couple $/MWh Hydro: few $/MWh Solar: $0/MWh Natural Gas: cost in $/MWh is 7 to 20 times fuel cost in $/MBtu; for example, with $8/MBtu gas, cost is $56/MWh to $160/MWh.
Energy Energy: Integration of power over time, Energy is what people really want from a power system, How much work you accomplish over time. Energy Units: Joule = 1 watt-second (J) kWh – kilowatthour (3.6 x 106 J) Btu – 1055 J; 1 MBtu=0.292 MWh U.S. electric energy consumption is about 3600 billion kWh (about 13,333 kWh per person, which means on average we each use 1.5 kW of power continuously).
Power Power: Instantaneous rate of consumption of energy, How hard you work! Power = voltage x current for dc Power Units: Watts = amps times volts (W) kW – 1 x 103 Watt MW – 1 x 106 Watt GW – 1 x 109 Watt Installed U.S. generation capacity is about 900 GW ( about 3 kW per person) Maximum load of Austin about 2500 MW. Maximum load of UT campus about 50 MW.
Simple Power System • Every power system has three major components: • generation: source of power, ideally with a specified voltage and frequency • load or demand: consumes power; ideally with a constant resistive value • transmission system: transmits power; ideally as a perfect conductor • Additional components include: • distribution system: local reticulation of power, • control equipment: coordinate supply with load.
Complications No ideal voltage sources exist. Loads are seldom constant and are typically not entirely resistive. Transmission system has resistance, inductance, capacitance and flow limitations. Simple system has no redundancy so power system will not work if any component fails.
Power System Examples Electric utility: can range from quite small, such as an island, to one covering half the continent: there are four major interconnected ac power systems in North America (five, if you count Alaska), each operating at 60 Hz ac; 50 Hz is used in Pakistan Airplanes and Spaceships: reduction in weight is primary consideration; frequency is 400 Hz. Ships and submarines. Automobiles: dc with 12 volts standard and higher voltages used in electric vehicles. Battery operated portable systems.
Goals of Power System Operation Supply load (users) with electricity at specified voltage (110 ac volts common for residential), specified frequency, at minimum cost consistent with operating constraints, safety, etc.
Major Impediments Load is constantly changing: Power system is subject to disturbances, such as lightning strikes. Engineering tradeoffs between reliability and cost.
Units of Energy • The Capacity of an agent to do work is known as energy • Mechanical, electrical and thermal energy • Mechanical energy • Unit is Newton-meter or joule • Mech energy in jouls=Force in newtonxdistance in meters • Electrical energy units watt-sec or joule • One watt-sec or I joule of energy is transferred between two points if p.d. of 1 volt exists between them and one ampere of current passes for one second. • Elect energy in watt-sec or jouls=Voltage in voltsxCurrent in ampxtime in seconds
Units of Energy • 1 watt-hour=1wattx1hour • =1wattx3600sec=3600 watt-sec • 1kilowatthour=1kwx1hour=1000wattsx3600se • =36x1o^5 watt sec • Heat • Heat is form of energy which produces sense of warmth. Units are Calorie, British thermal units (B.T.U) and centigrade heat units (C.H.U)
Units of Energy • Calorie • Amount of heat required to raise the temperature of 1 gm of water through 1 Centigrade. • Ikcal=1Kgx 1C=1000gmx1C=1000 Calories • BTU • Amount of heat required to raise temp of 1 lb of water through 1 F • CHU • Amount of heat required to raise temp of 1 lb of water through 1 C
Relationship among energy units • i) Electrical and Mechanical • 1KWh=1kwx1Hr=1000Wattsx3600Sec • =36X10^5watt-sec or joules ii) Heat and Mechanical • 1 Calorie=4.18 J (By experiment) • 1CHU=1lbx1C=453.6 gmsx1C=453.6Cals =453.6X4.18=1896 JOULS c) 1BTU=1lbX1F=453.6 gramsx5/9C=252 Calories =252x4.18 joules=1053 jouls
Relationship among energy units • iii) Electrical and Heat • 1KWh=3600000 Joules=3600000/4.18=860x10^3 Calories=860Kcals b) 1KWH=36X10^5 Joules=36x10^5/1896CHU=1898 CHU c) 1kWh=36x10^5/1053 BTU=3418 BTU
Efficiency • Output energy divided by input energy is called energy efficiency • Question • Energy is supplied to a d.c. generator at the rate of 4200 J/s. Generator delivers 32.2 A and 120 V • Calculate % efficiency of the generator? • How much energy is lost per minute of operation? • Ans • Input Power=4200J/s=4200W • Out put Power=EI=120X32.2=3864 W • %efficiency=3864/4200X100=92% • Power lost=4200-3864=336W • Energy lost per min=336X60=20160 J
Calorific value of Fuels • The amount of heat produced by the complete combustion of a unit wieght of fuel is known as its calorific value. In case of solid or liquid fuel, it is expressed as cal/gm or Kcal/kg. In case of gaseous fuels it is expressed as cal/litre or Kcal/lit
Comparison of fuels • Advantages of liquid fuels over Solid fuels • i) handling of liq fuel is easier. Require less space • Ii)Combustion of liquid fuel is uniform • Iii)Solid fuels have higher moisture. Burn with difficulty • Iv)Waste product ash is cumbersome to dispose • V) Firing of liquid fuel can be controlled easily. Hence easy to manage load
Comparison of fuels • Advantages of Solid fuels over liquid fuels • i) Liquid fuels danger of explosion • Ii)Liquid fuels are costlier • Iii)Sometimes liquid fuels generate unpleasant odour while burning • Iv)Liquid fuels require special type of burners • V) Liq fuels need to be heated in cold weather to avoid freezing
Generating Stations • Bulk electric power is produced by special plants known as generating stations or power plants • A generating station employs a prime mover coupled to an alternator for production of electric power • Prime mover ( steam turbine or water turbine) converts some other form of energy into mechanical energy. Alternator converts mech to elect
Classification of Generating stations • Steam power stations (Thermal ) • Hydroelectric power stations • Diesel power stations • Nuclear power stations
Steam Power Station • A generating station which converts heat energy of coal combustion into electrical energy is known as steam power station • Steam produced in boiler • Steam is expanded in prime mover and condensed in condensor • Steam turbine moves alternator which converts mechanical energy into electrical energy
Steam Power Station • Advantages • The fuel (i.e. coal) used is quite cheap • Less initial cost as compared to other generating stations • Installed at any location. Only coal needs to be transported • Requires less space as compared to hydroelectric • Cost of generation is less as compared to Diesel power stations
Steam Power Station • Disadvantages • Pollution of air • Running cost more than Hydroelectric stations
Steam Power Station • Schematic arrangement of Steam Power Station • 1 Coal and ash handling plant • Coal pulverised to increase surface exposure • Pulversied coal is fed to the boiler by belt conveyer. Coal burnt in boiler and ash removed • 100MW thermal power station on 50% load factor • Requires 20000 tons of coal per month; 10-15% of burned coal is ash produced
Steam Power Station • 2 Steam generating plant • Boiler • Super heater • Economizer • Air preheater • 3 Steam turbine • 4. Alternator • 5 Feed water • 6 Cooling arrangements
Choice of site for Steam Power Stations • Supply of fuel • Availability of water • Transportation facilities • Cost and type of load • Nearness to load center • Distance from populated areas liquid
Efficiency of Steam Power Station • Overall efficiency of steam power station is quite low because huge amount of heat is lost in the condensor and heat loss occurs at various stages (29% overall efficiency) • Thermal efficiency: the ratio of heat equivalent of mechanical energy transmitted to the turbine shaft to the heat of combustion of coal is known as thermal efficiency of steam power station: 30%thermal efficiency • Overall efficiency: the ration of heat equivalent of electrical output to the heat of cumbustion of coal is known as overall efficiency: 29%