Auxiliary power is electric power that is provided by an alternate source It serves as backup for the primary power source auxiliary system power supply in large power plants is a key factor for normal operation, transient states, start-ups and shutdowns during fault conditions Depending upon the type of fuel and environmental control system required, a thermal power plant may consume as much as 10% of its total generation for auxiliary power

1. Career Point Cares
CAREER POINT UNIVERSITY
POWER ENGINEERING ASSIGNMENT
Submitted to: Submitted by:
MR. KAMAL ARORA ALFIYA SHEIKH
DEAN B.TECH EE
CPU 3rd yr/5th sem
UID=K11617

2. AUXILIARY POWER SUPPLY SCHEME
FOR THERMAL POWER PLANT

3. CONTENTS
• THERMAL POWER PLANT
• AUXILIARY POWER
• AUXILIARY SYSTEMS
 BOILER AUXILIARIES
 BOILER MAKE-UP WATER TREATMENT PLANT AND STORAGE
 FUEL PREPARATION SYSTEM
 BARRING GEAR
 OIL SYSTEM
 GENERATOR COOLING
 GENERATOR HIGH-VOLTAGE SYSTEM
 MONITORING AND ALARM SYSTEM
 BATTERY-SUPPLIED EMERGENCY LIGHTING AND COMMUNICATION
 CIRCULATING WATER SYSTEM

4. THERMAL POWER PLANT
Thermal power station is a power plant in
which heat energy is converted to electric power.
• In most of the places the turbine is steam-driven
• Water is heated, turns into steam and spins
a steam turbine which drives an electrical
generator

5. AUXILIARY POWER
• Auxiliary power is electric power that is provided
by an alternate source
• It serves as backup for the primary power source
• auxiliary system power supply in large power
plants is a key factor for normal operation,
transient states, start-ups and shutdowns during
fault conditions
• Depending upon the type of fuel and
environmental control system required, a thermal
power plant may consume as much as 10% of its
total generation for auxiliary power

6. Auxiliary systems
• steam generating plant consists of a boiler for the
production of steam and other auxiliary
equipment for the utilization of flue gases
BOILER
• The heat of combustion of coal in the boiler is
utilized to convert water into steam
• The flue gases from the boiler make their journey
through superheater , economiser ,air pre-heater
and are finally exhausted to atmosphere through
the chimney.

7. BOILER AUXILIARY
• FORCED DRAUGHT FAN
• INDUCED DRAUGHT FAN
• PRIMARY AIR FAN
• SUPER HEATER
• ECONOMISER
• AIR PRE-HEATER

8. ECONOMISER extracts a part of heat from the
flue gases and uses for heating the feed water.
SUPER HEATER is used to remove the moisture
content from the steam (above 540 degree C)
AIR PRE-HEATER is used to preheat the air before
entering into furnace

10. Boiler make-up water treatment plant
and storage
• to maintain desired water level in boiler steam
drum continuous make-up water is added to
boiler
• Water is hard due to Impurities(ca & mg) in the
raw water input
• Hardness will form deposits on the tube water
surfaces which will lead to failure of the tubes.
• Thus, the salts have to be removed from the
water by a water demineralising treatment plant
(DM)
• The storage tank for DM water is made from PVC

11. Fuel preparation system
Three types of fuels can be burnt in steam
generating plant : solid,liquid,gas
The boiler furnace auxiliary equipment includes
• coal feed nozzles
• igniter guns
• soot blowers
• water lancing
• observation ports (in the furnace walls) for
observation of the furnace interior

12. • In coal-fired power stations, the raw coal is
first crushed into small pieces and then
conveyed to the coal feed hoppers at the
boilers.
• The coal is next pulverized into a very fine
powder.
• The pulverizers are types of grinders.

13. Barring gear
• Barring gear is the mechanism provided to rotate
the turbine generator shaft at a very low speed
after unit stoppages.
• Once the unit is tripped there is a tendency for
the turbine shaft to bend
• small shaft deflection detectable by eccentricity
meters
• Disadvantage cause vibration
• The shaft is therefore automatically turned at
low speed by the barring gear until it has cooled
sufficiently to permit a complete stop

14. Oil system
• An auxiliary oil system pump is used to supply oil
at the start-up of the steam turbine generator.
• It supplies the hydraulic oil system required for-
 steam turbine's main inlet steam stop valve
 governing control valves
bearing and seal oil systems
and other mechanisms.

15. Generator cooling
• Hydrogen gas cooling, used because it has highest
known heat transfer coefficient
• This system requires special handling during start-
up air in the generator first displaced by carbon
dioxide before filling with hydrogen. This ensures
that the highly flammable hydrogen does not mix
with oxygen in the air.
• The hydrogen pressure inside the casing is
maintained higher
• Seal oil is used to prevent the hydrogen gas
leakage

16. Generator high-voltage system
• generator voltage ranges from 11 kV to 30 kV
• generator high-voltage leads are large
aluminium channels because of high current
• enclosed in well-grounded aluminium bus
ducts and are supported on suitable insulators
• The necessary protection and metering
devices are included for the high-voltage leads

17. Monitoring and alarm system
• Most of the power plant operational controls
are automatic. However, at times, manual
intervention may be required
• plant is provided with monitors and alarm
systems that alert the plant operators when
certain operating parameters are seriously
deviating from their normal range.

18. Battery-supplied emergency lighting
and communication
• A central battery system consisting of lead acid
cell units units is provided to supply emergency
electric power
• It supply emergency electric power to-
 power plant's control systems
 communication systems
generator hydrogen seal system
 turbine lube oil pumps
emergency lighting
This is essential for a safe, damage-free shutdown
of the units in an emergency situation.

19. Circulating water system
• To dissipate the thermal load of main turbine
exhaust steam a continuous supply of cooling
water is provided to the main condenser
thereby leading to condensation

20. THANK YOU