REPORT ON“GENERATION OF THERMAL POWER”ATNTPC DADRI

BY-Shivam SharmaECE 4Th year

About NTPC• NTPC, the largest power Company in India, was setup

in 1975 to accelerate power development in the country. • NTPC has installed capacity of 29,394 MW.• It has 15 coal based power stations (23,395 MW)• 7 gas based power stations (3,955 MW)• 4 power stations in Joint Ventures (1,794 MW). • The company has power generating facilities in all major

regions of the country. • It plans to be a 75,000 MW company by 2017.

Generation of Electricity• Prime mover coupled to

Alternator• Prime mover is driven by

energy obtained from various sources such as

• burning of fuel• pressure of water• Force of wind etc.

Fig. Fundamental of generation of Electricity

ABOUT NTPC Dadri

National Capital Power Station (NCPS) Or NTPC Dadri, is the power project to meet the power demand of National Capital Region (India). It has a huge coal-fired thermal power plant and a gas-fired plant and has a small township located in Uttar Pradesh, India for its employees. It is located in Gautam Budh Nagar district of Uttar Pradesh about 25 km from Ghaziabad and about 9 km fromDadri. It is nearly 48 km from New Delhi towards Hapur.NTPC Dadri plant and township are property of ntpc ltd and were built around 1988-1990. NTPC Dadri is a unique power plant of NTPC group which has both coal based thermal plant and gas based thermal plant of 1820 MW and 817 MW respectively and 5 MW solar plant totaling 2642 MW..

Thermal Power Plant• A generating station which converts heat energy of coal combustion

into electrical energy is known as a steam power station.• Steam is produced in the boiler by utilizing the heat of coal

combustion. The steam is then expanded in the steam turbine and is condensed in a condenser to be fed into the boiler again. The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical energy.

WORKING OF STEAM POWER PLANT

• Coal is burnt in a boiler ,which converts water into steam.• The steam is expanded in a turbine used to drive alternator.• The steam expanded is condensed in a condenser to be feed into

the boiler again.• The entire arrangement of steam power plant can be divided into :

a. fuel and ash plant.b. air and fuel gas plant.c. feed water and steam plant.d. cooling water plant.

In a fire tube boiler, the hot products of combustion pass through the tubes surrounded by water.

• The heated water then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. The steam will reenter the furnace in through a superheater in order to become superheated. Superheated steam is used in driving turbines. Since water droplets can severely damage turbine blades, steam is superheated to 730°F (390°C) or higher in order to ensure that there is no water entrained in the steam.

Super heater• A device which removes last traces of

moisture.• It helps in reduction in requirement of

steam quantity.• steam being dry reduces the mechanical

resistance of turbine.• No corrosion at the turbine blades.

Economiser and Air Pre-heater• They are such devices which recover the

heat from the flue gases on their way to chimney and raise the temperature of feed water.

• Economiser raises boiler efficiency.• Air Pre-heaters recover the heat from the

flue gases leaving the economiser and heat the incoming air required for combustion

Condenser• Which condenses the steam at the exhaust of turbine.• It creates a very low pressure at the exhaust of turbine,

this helps in converting heat energy of steam into mechanical energy in the prime mover.

• The condensed steam can be used as feed water to the boiler.

Prime Mover (i.e. Turbine)A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into mechanical energy.About 86% of all electric generation in the world is by use of steam turbines.It has almost completely replaced the reciprocating piston steam engine.

BOILER GENERATOR

STEAM TURBINE

Cooling Towers• Remove heat from the

water discharged from the condenser so that the water can be discharged to the river or re circulated and reused.

• Air can be circulated in the cooling towers through natural draft and mechanical draft.

Electrical EquipmentsAlternatorAn alternator is coupled to a steam turbine and converts mechanical energy of the turbine into electrical energy.It may be hydrogen or air cooled.The necessary excitation is provided by means of main and pilot exciters directly coupled to the alternator shaft.Transformers(a) main step-transformers, which steps-up generated voltage transmission of power(b) station transformers, general purpose(c) auxiliary transformers, which supply to individual unit-auxiliaries.Switchgearwhich locates fault on the system and isolate faulty part from healthy section.It contains circuit breakers, relays, switches and other control devices.

Control and Instrumentation Department of NTPC

Control and Instrumentation Department is the brain of NTPC.

This division calibrates the various instruments and take care of any fault in plant.

Control and Instrumentation Department has following labs:1. Manometry Lab.2. Protection and Interlocking Lab.3. Automation Lab.4. Electronics Lab5. Pyrometry Lab6. Furnace Safety Supervision Lab.

MANOMETRY LABTRANSMITTERS:-It is used for the pressure measurement of gases and liquid in power plant.Its working principle is input pressure is converted into the electrostatic capacitance and then it is conditioned and amplified.It gives output of 4-20 ma DC. Manometer :-It is a tube which is bent in U shape .It is filled with a liquid .This device corresponds to a difference between pressure across two limbs.

Protection and Interlocking• It is basically interconnecting two or more equipments if one

equipment fail then other will perform the task.• This also helps in interconnected equipment shutdown and started in

sequence to avoid damage.• For Protection Tripping are provided for all equipments.• Tripping is instruction provided to all equipment in series by OR

gate.RELAYIt is a Protective device .It can detect wrong condition in electrical circuits by constantly monitoring electrical quantities flowing under normal and faulty condition..These quantities are voltage ,current ,phase angle and velocity.

PYROMETRY LABULTRAVOILET SENSORThis is the device in furnace and it measure the intensity of ultraviolet rays there wave intensity directly indicates the temperature in furnace.

THERMOCOUPLESIt comprises of two junction at different temperature.The emf induced in the circuit due to flow of electron .That emf is calibrated to measure temperature.

RTD(Resistance Temperature detector)In this due to the change in resistance difference temperature is measured.

FURNACE SAFETY AND SUPERVISORY LABIn first coal burners are in front and rear of the furnace and in second stage corner firing is employed.Unburnt coal is removed by induced draft fan .The boiler temperature is about 1100 Celsius and its height about 18 to 40 m.Ultraviolet sensor continuous monitor the temperature of furnace.HSD supply with firing of 10kv spark upto 10 sec for ignition of furnace.

Electronics LabThis lab undertake the calibration and testing of various cards . It is a house of various type if instruments like oscilloscope, IC cards and analyzer .Annuciatin Cards They are used to keep any parameter in limits like temperature etc.It shows the signal if parameter goes beyond the limit.

CONTROL & MONITORING MECHANISMSThere are basically two types of Problems faced in a Power Plant• Metallurgical• MechanicalMechanical Problem can be related to Turbines that is the max speed permissible for a turbine is3000 rpm so speed should be monitored and maintained at that level. Metallurgical Problem can be view as the max Inlet Temperature for Turbine is 1060°C.so temperature should be below the limit. Monitoring of all the parameters is necessary for the safety of both machines and employees. 

These are following parametres that requires continuous monitoring

• Pressure monitoring• Temperature monitoring• Flow measurement =>Rotameter-A rotameter is a device that measures the flow of liquid and gas in a closed tube. =>Venturimeters Flow = k √ (D.P) D.P= (ρ/2)(v2

2- v12)

• Control valves =>They regulate the flow of substance (gases , liquid)