Major electrical equipment in power plants include alternators, exciters, synchronizing equipment, circuit breakers, current and potential transformers, relays, protection equipment, isolators, lightning arresters, earthing equipment, station transformers, and batteries and motors for driving auxiliaries. The document goes on to describe each type of equipment in more detail, including their purpose and features. It discusses equipment such as generators, exciters, power transformers, voltage regulators, bus bars, reactors, insulators, switchgear, switches, protective equipment like fuses and circuit breakers, relays, current transformers, potential transformers, batteries, and control rooms.

1. MAJOR ELECTRICAL
EQUIPMENT IN POWER
PLANTS
Submitted To:- Er. Sonika Singh
Presented By :- Gurdit Singh
1184238
EE 2k10

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. 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. Turbo generator for thermal power station

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.  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. 230KV Power Transformer in Gas
Plant

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.  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. Bus -Bar

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.  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.  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. 230KV Switchgear

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.  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.  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.  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.  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. 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.  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.  1. Latching relay
 2. Reed relay
 3. Mercury relay
 4. Polarized relay
 5. Solid-state relay
Relay
Types of relay

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.  It is normally a step-down transformer
 Secondary winding has a 5 ampere value of current to
the rated current of primary winding

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.  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.  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. Control room in thermal power plant

29. Thank You