Major electrical equipment in power plants


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Electrical engg equipments used in various power plants

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Major electrical equipment in power plants

  1. 1. MAJOR ELECTRICAL EQUIPMENT IN POWER PLANTS Submitted To:- Er. Sonika Singh Presented By :- Gurdit Singh 1184238 EE 2k10
  2. 2.  Power plant consists of Variety of electrical equipment  Major electrical equipment are Alternator, Exciters, Synchronizing Equipment, Circuit Breakers, current and potential transformers, relays and protection equipment, isolator, lighting arresters, earthing equipment, station transformer, battery and motor for driving auxiliaries Introduction
  3. 3. In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric current to flow through an external circuit. Generator are varies in type according to the type power plant Generator decide the size of power plant Generators
  4. 4. Turbo generator for thermal power station
  5. 5.  Excitation system is required to provide the necessary field current to the rotor winding of a synchronous machine. Availability of excitation at all times important. Larger the load currents, lower the speed and lagging power factor which require more excitation.  Types  1. DC Excitation System 2. AC Excitation System  3. Static Excitation System Exciters
  6. 6.  Power transformer are used for stepping-up the voltage for transmission at generating stations and for stepping-down voltage for distribution purpose.  Normally naturally cooled, oil immersed, two winding, three phase transformers are used up to the rating of 10 MVA.  For regulating the voltage , transformers are provide with on load tap changers  They are put in operation during large load hours and disconnected during light load hours Power Transformer
  7. 7. 230KV Power Transformer in Gas Plant
  8. 8.  Every alternator provide with automatic voltage regulator which perform following function  1. Control of voltage within prescribed limits.  2. Proper division of reactive power b/w alternator operating in parallel.  3. Prevention of dangerous over-voltage in system.  Types  Using Transformer  Induction Voltage Regulator  Now-a-days Electronic voltage regulators are used for greater sensitivity and accuracy. Voltage Regulators
  9. 9.  Bus bar is a main bar or conductor carrying an electric current to which many connections are to be made.  Usually two buses are provided in a system one is called the “Main” bus and other “Auxiliary ” or transfer bus  There are many shapes of bus bar available like round tubes, round solid bars or square tube  Material used for bus bar is aluminum because it has high corrosion resistance than copper and lower cost.  Bus bar of 5 to 6 meter in length Bus- Bars
  10. 10. Bus -Bar
  11. 11.  Reactor is a coil having large inductive reactance in comparison to its resistance.  It is used in the circuit to limit the short circuit currents to a safer value in order to protect the electrical installation  As their reactance is very small, the efficiency of the system is not affected.  It avoid the faulty current to flow through the healthy system.  Types of reactor  1. Open type  2. Oil Immersed type Reactors
  12. 12.  The porcelain insulators are used to support the bus-bar  It also provide the insulation to the bus-bar from pole to ground  Current rating of porecelain is above 2000A Post type insulator Insulators
  13. 13.  During the operation of power system the generating plants, transmission lines, distributors and other electrical equipment are required to be switched on and off under both normal and abnormal conditions Switchgears are used  All the protection equipment like switches, fuse, Circuit breakers, relays are installed in switchgear  Types  1. Outdoor type  2. indoor type  For the voltage above the 66KV outdoor switchgears are installed Switchgear
  14. 14. 230KV Switchgear
  15. 15.  A switch is a device which is used to making or breaking the electric circuit. By simple motion of a knob or handle  They can make or break the circuit during normal and abnormal conditions  Types  1. Air switches  2. Oil switch Oil switches are used in high voltage and heavy current circuit Switches
  16. 16.  Protective equipment are very important in system to isolate the abnormal conditions  Feature of protective equipment  1. greater reliability  2. High speed of operation  3. Simple and withstand to large value of fault  Various Protective equipment are  Fuse, Circuit Breakers, Relays, Lightning arresters Protective Equipment
  17. 17.  Fuse is a wire of short length or thin strip of material which melt with the flow of excessive current  Under normal working conditions safe value of current flows but during short circuit load current increased which heat the wire so wire melt and circuit break  Advantages:-  1. cheap in cost  2. needs no maintance  3. it interrupts short-circuit current without noise, flame, gas or smoke. Fuse
  18. 18.  4. Under short circuit condition it limits the current  5. By the use of inverse time characteristic it is easily provided for over load protection. Disadvantages of fuse:-  1. wire should be replaced after every operation Rewire able Kit-Kat Fuse
  19. 19.  A circuit breaker is a mechnical device used to open and close contact under normal and abnormal conditions  Relay is use as a sensor with circuit breaker for automatic operation  Circuit breaker carry normal current without over- heating or damage Function of circuit breaker:-  1. To carry full load current continuously  2. To open and close the circuit under no load  3. To break the circuit under short-circuit condition Circuit Breakers
  20. 20. According to voltage level  1. Low Voltage CB :- V < 1000Vac , I up to 100A  2. Medium voltage CB:- V up to 72KV , I up to 6300A  3. High voltage CB:- v up to 1200KV , I > 6300A Miniature Circuit Breaker Types of Circuit Breakers
  21. 21.  Relay is electro-mechnical device which sense the excessive flow of current and send signal to the circuit breaker  Relay has three essential elements  1. Sensing element- it sense and measure the change  2. Comparing element- compare the measured quantity to pre-setted value  3. Controlling element- it sends signal to circuit breaker Relays
  22. 22.  1. Latching relay  2. Reed relay  3. Mercury relay  4. Polarized relay  5. Solid-state relay Relay Types of relay
  23. 23.  It is an instrument transformer which is used to measure the current from high voltage line with the use of normal ampere meter.  High currents or voltages of electrical power system can not be directly fed to relays and meters. CT steps down rated system current to 1 Amp or 5  The relays and meters are generally designed for 1 Amp, 5 Amp and 110V. Current Transformer
  24. 24.  It is normally a step-down transformer  Secondary winding has a 5 ampere value of current to the rated current of primary winding
  25. 25.  It is also a instrument transformer which is used to measure the voltage above 380 volts  PT make the ordinary low voltage instrument suitable for measurement if high voltage and isolate from high voltage.  When rated high voltage is applied to primary of PT, it give the secondary voltage of 110 volts Potential Transformer
  26. 26.  All power plant and sub-stations DC supply for protection and control purpose  DC supply is provided from Storage batteries.  Lead acid battries mostly used in power stations because their higher cell voltage and lower cost Batteries
  27. 27.  Control room is nerve centre of the power station  Various controls like Voltage adjustments, load control, emergency tripping of tubine and other equipment and instruments are housed in the control room.  Location of control room is away from noise and should near to the switch house  There should be no glare , neat and clean, well ventilated and free from draughts Control Rooms
  28. 28. Control room in thermal power plant
  29. 29. Thank You