Introduction of Electricity

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This is a very simple presention abouth electricity, what is electricity & how it produced and distribute.

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  • We all use it but what exactly is it? To understand electricity we have to think of tiny particles so small we cannot see them with our own eyes: they’re called electrons and they’re inside the smallest particles called atoms . Atoms have nucleus orbited by one or more electrons, each with a negative charge. In many types of material – wood, glass, plastic, ceramic, air, cotton – the electrons are tightly bound to the atoms. Because the electrons don’t move, they don’t conduct electricity very well. They’re called electrical insulators . Metals have electrons that detach from the atom and move around quickly. These are called free electrons. These free electrons allow electricity to flow through metals, so they’re called electrical conductors . Moving electrons transmit electrical energy from one point to another. Electricity needs a conductor in order to move. It also needs something to make electricity flow from one point to another through the conductor. One way to get electricity flowing is to use a generator.
  • The Power Plant This is where electrical power begins. In most cases, the plan consists of a spinning electrical generator . Something – some kind of force or pressure - has to make the generator spin. It might be a water wheel (or turbine) in a hydroelectric dam, a large diesel engine, or a gas turbine. Often the thing spinning a generator is a steam turbine. The steam is created by burning coal, oil or natural gas. Or the steam may be generated in a nuclear station.
  • Introduction of Electricity

    1. 1. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Introduction to Electricity
    2. 2. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Introduction to Electricity Basic Electricity How Central Power Grids Work Electricity Generation
    3. 3. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Part 1: Electricity Concepts What is Electricity? Electrons, atoms, negative charge Conductors (example?) Insulators (example?) Electrical energy Magnet
    4. 4. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company In September of 1831, Michael Faraday made the discovery of Electromagnetic Induction.
    5. 5. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company What does copper wire and magnets have to do with Electricity? Faraday attached two wires to a disc and rotated the disc between the opposing poles of a horseshoe magnet creating an electric current.
    6. 6. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electric current generation - whether from fossil fuels, nuclear, renewable fuels, or other sources is usually based on the:
    7. 7. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company How does a generator work? A generator is simply a device that moves a magnet to create a steady flow of electrons. What moves the magnet? Water, or high pressure steam or gas drive turbine blades.
    8. 8. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Process of Generation
    9. 9. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electrical Units Three basic units of measurement: Voltage (volts) Current (amps) Resistance (ohms)
    10. 10. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Water Analogy Voltage ~ water pressure Current ~ flow rate Resistance ~ pipe size
    11. 11. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Key Concept Let’s say you have a tank of pressurized water connected to a hose that you use to water your vegetable garden. If you increase the pressure in the tank, more water comes out of the hose. Same for electrical systems: increase the voltage: you get a higher current of electrons. OR if you increase the size of the hose more water can flow out. This is like reducing resistance in an electrical system, so you get more current.
    12. 12. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Basic Electrical Circuit All circuits have basic components: a source of electricity (such as a battery), a load (a light or motor) and two wires to carry electricity between the two. Electrons move from the source, through the load, and back to the source. These moving electrons have what we call energy. As they move they can do work.
    13. 13. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Key Concept In an electrical system, increasing either the current (i) or the voltage (V) will increase power output (P). Increase resistance in the wires, voltage drops, current drops > power output drops.
    14. 14. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electrical Circuits Battery is a simple electrical circuit and source When you load a battery into an electronic device, the negatively charged electrons will travel to the portion of the battery with a positive charge - much like water flowing down a stream and being forced to turn a water wheel.
    15. 15. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company How to calculate electricity consumption In a light bulb, electrical energy creates heat in the bulb, and the heat then creates light. How much power in kilowatt-hours does a 100- watt lightbulb use in a year? 0.1 kW x 8,760 hours in a year (24 x 365) or 876 kilowatt-hours (kWh)
    16. 16. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Household Electricity Consumption In Pakistan, the power outlets in the wall deliver 220 volts each. The frequency or the current is 50 cycles per second. If you know the amps and volts, you can determine the amount of electricity consumed, which is measured in watts. Most appliances are rated in watts. Say your appliance consumes 1,200 watts or 1.2 kilowatts. If you leave the appliance on for one hour the amount of electrical energy consumed is 1.2 kilowatts per hour.
    17. 17. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Your Electricity Bill Power is measured in watts (voltage x current) Consumption is measured in kilowatt-hours How much does the power company charge you for electricity?
    18. 18. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electrical Current Direct Current (DC) Batteries (and solar cells) produce DC. The positive and negative terminals of a battery are always positive and negative. Current always flows in the same direction between the two terminals.
    19. 19. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electrical Current Alternating Current (AC) Power from a power plant is AC. The direction of the current reverses or alternates. In Pakistan, AC moves at 50 cycles per second. Power from a wall socket is 220 volts, 50- cycle single-phase AC power.
    20. 20. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Key Concept There is an advantage in using less current to make the same amount of power. The resistance in electrical wires consumes power; as current increases, more power consumed. Using a higher voltage to reduce the current makes electrical system more efficient.
    21. 21. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Part 2: How Central Power Systems Work
    22. 22. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company The Power Plant This is where electrical power begins. In most cases, the plant consists of a spinning electrical generator. Something – some kind of force or pressure - has to make the generator spin. It might be a turbine in a hydroelectric dam, a large diesel engine, or a gas turbine. Often a steam turbine is used to spin the generator. The steam is created by burning coal, oil or natural gas. Or the steam may be generated in a nuclear station.
    23. 23. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Power Plants Generate 3-phase AC Power Commercial generators of any size generate what is called 3-phase AC power. There are 4 wires coming out of every power plant – the three phases plus a ground.
    24. 24. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Transmission Substation 3-phase power leaves the generator and enters a transmission substation at the power plant. This substation uses large transformers to convert the generator’s voltage (thousands of volts) up to extremely high voltages for long distance transmission on the grid. In Saba Power generation voltage is 15.5 kv, a step-up power transformer covert 15.5 kv to 132 kv.
    25. 25. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Transmission Lines Typical voltages for long distance transmission range from 132 to 765 kilovolts (1 kilo is 1000) In Pakistan transmission range is 132 to 500 kv. A typical long distance transmission is under 500 kilometres.
    26. 26. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Power Substation The power substation does 2 or 3 things: transformers bring down the voltage to distribution voltages. a busbar splits the distribution power off in multiple directions. circuit breakers and switches to allow the substation to be disconnected from the transmission grid or separate distribution lines.
    27. 27. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Electricity Distribution To use power in homes and markets, power from the transmission grid must be stepped down to the distribution grid. Conversion from transmission voltage to standard line voltage 11 kV (kilovolts)
    28. 28. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Distribution Line to End Users The transformer steps down electricity from 11 kilovolts to 3Ф400/230 volts for normal household electrical service. The 3 phase 400 or single phase 230 volts enters your house through a typical watt-hour meter. The meter allows the power company to charge you (the end user) the cost of putting up all these wires and consuming electricity delivered to your house, office, factory, etc.
    29. 29. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Key Concept AC power has one big advantage: voltage can be changed (up or down) using a device called a transformer. Power companies save money using very high voltages to transmit power over long distances.
    30. 30. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Part 3: Electricity Generation Generation Technologies Steam turbines Gas turbines Wind turbines Hydro/hydraulic turbines Combined cycle plants Cogeneration Microturbines Solar photovoltaics (DC power)
    31. 31. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Fossil Fuel Plants Use Steam Turbines
    32. 32. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Saba Power Plant Arial View
    33. 33. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Nuclear Reactors use steam turbines
    34. 34. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Biomass Generation
    35. 35. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Biomass Gasifier Power Plant
    36. 36. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Combined Cycle Power Plants use gas & steam turbines
    37. 37. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Combined Cycle Plants use gas turbine and steam turbine
    38. 38. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Solar Photovoltaics
    39. 39. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Solar: On-Grid/Off-Grid Technology
    40. 40. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Characteristics of Generating Plants Size, generating capacity Energy/fuel source Efficiency – conversion to electrical energy Type of use Availability
    41. 41. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Generation: Capacity Depends on size of the hydraulic turbine, the electric generator and the height of the water (head). The volume of water behind the dam affects the maximum amount of energy that may be generated in a given period of time.
    42. 42. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Power Plant – Size (Capacity) Range from a few kilowatts to >1,000 MW Microturbines are the smallest
    43. 43. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Generation: Efficiency The efficiency of a generating unit is a measure of the amount of electrical energy produced per unit of energy input. For thermal plants (plants burning fuel), the energy input is fuel and the way efficiency is measured is called the heat rate. The more fuel that has to be burned to produce electricity, the lower the thermal efficiency.
    44. 44. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Comparing Plant Efficiency Newer combined cycle plants have near 50 percent thermal efficiency compared to simple cycle or nuclear plants which can only convert 30 percent of their fuel into electrical energy (the rest is released into the atmosphere as waste heat).
    45. 45. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Type of Use: Base, Intermediate, Peak Load In a central power system, power plants are designed and operated for: base load, intermediate load, and peak load. Base load – usually large units with low operating costs. Usually operated at full capacity during most of the hours they are available. Designed to operate for long periods of time at or near maximum dependable capacity. Low operating costs refer to low cost of the fuel they use.
    46. 46. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Intermediate Load Power plants used to respond to variations in customer demand which occur during the day. Plants designed for change in output levels.
    47. 47. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Type of Use: Peak Load Peak load – power plant is called upon to supply customer demand during peak (= highest) load hours of a given day, month, season or year. Combustion turbines and small hydro units – usually less than 150 MW, capable of achieving full load operation within 10 minutes. They may also be used to replace capacity of other units that have suddenly been taken off the system due to forced outages. While steam power units usually takes 20 to 30 minutes to achieve load from minimum to maximum or vise versa.
    48. 48. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Plant Availability & Dispatch System operators are concerned about availability of each power plant to supply the grid. System operators (NTDC) dispatch power plants according to their availability (and operating cost). On a day to day and hour to hour basis there must sufficient generation synchronized to the grid to meet all load requirements and respond to short-term variations in customer load, as well as cover for the loss of another generator.
    49. 49. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Availability vs Outages Unavailability of a generating unit due to component failure is called a forced outage. Various components of generating units must be removed from service on a regular basis for preventive maintenance or to replace components before a forced outage results – this is called a planned outage.
    50. 50. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Power System Reliability 80 to 90 percent of power disruption in power systems today are caused by transmission grid, not generation. Voltage dips in major transmission line > other transmission lines within the system pick up additional load and may require central utility to redispatch generation >instability, overloading, blackouts.
    51. 51. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company Reserve Capacity Central power systems designed to meet demand plus a reserve capacity, over and above the expected peak load obligation of the power plant (15 to 45 %). Today big questions within the industry: should the amount of installed generating capacity should be a design requirement (set by government) or should be determined by the market; who should pay for transmission? [MORE TOMORROW].
    52. 52. February, 2010 Mohammad Shoeb Siddiqui Sr. Shift Supervisor Saba Power Company END: Introduction to Electricity

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