badarpur thermal power station

BADARPUR THERMAL POWER STATION

SUMMER TRAINING REPORT31ST MAY- 10TH JULY’ 2010

SUBMITTED BY:BHAGYASHREE PACHISIA

EEE, 3rd YEAR

1. Introduction NTPC

Badarpur Thermal Power Station 2. Operation 3. Electrical Maintenance Division-I

Turbine & Boilers Site LT/HT Switchgear

CHP/NCHP 4. Electrical Maintenance Division-II

Generator Transformer & Switchyard

CONTENTS

ABOUT THE ORGANIZATION NTPC limited is the largest thermal power generating company of the India, Public sector company.

It was incorporated in the year 1975 to accelerate power development in the country as a wholly owned company of the government of India.

At present, Government of India holds 89.5% of the total equity of shares of the company and the balance10.5% is held by FIIs, domestic banks, Public and others.

NTPC’S core business is engineering, construction and operation of power generating plants and providing consultancy’s to power utilities in India.

Total installed capacity of the company is 31134 MW including JV’s with 15 coal based and 7 gas based stations across the country.

VISION

“A world class integrated power major, powering India's growth with increasing global presence.”

MISSION

Develop and provide reliable power related products and services at competitive prices, integrating multiple energy resources with innovative & Eco-friendly technologies and contribution to the society.  

STRATERGIES

THERMAL POWER PLANT

In a thermal power plant, one of coal, oil or natural gas is used to heat the boiler to convert the water into steam. The steam is used to turn a turbine, which is connected to a generator. When the turbine turns, electricity is generated and given as output by the generator, which is then supplied to the consumers through high-voltage power lines.

BADARPUR THERMAL POWER STATION

Approved capacity - 705 MW Installed capacity - 705 MW

Coal source - central coal field limited, Indian cooking coal limited, eastern collieries and Jharia coal mines Water source - Agra canal Oil source - Indian Oil Beneficiary state - Delhi

LAYOUT OF A THERMAL POWER PLANT

COAL HANDLING DEPARTMENT• The processing of coal before it is fired to the furnace, comes

under the coal handling division of the power plant.

• At BTPS we have two CHD-• OCHD- UNITS 1,2,3• NCHD- UNITS 4,5

• The Coal Handling Division of BTPS has the following parts:

Railway Wagon Triplero Conveyoro Coal Storage Groundo Separatoro Pulverizer or Bowl Mill

Railway Wagon Tripler Conveyor

Coal Storage Ground Separator

• Pulverizers are used to crush it into fine powered particles.

Pulverizer

Fired to the Boiler Furnace for combustion

WATER DEMINERALISING TREATMENT PLANT

Raw water input to the plant generally consist of calcium and magnesium salts which impart hardness.

This will form deposits on the tube water surfaces which will lead to overheating and failure of the tubes.

A DM plant generally consists of cation, anion and mixed bed exchangers.

The storage tank for DM water is made from materials not effected by corrosive water, such as PVC. The piping and valves are generally of stainless steel.

MAIN UNITS OF THERMAL POWER PLANT

STEAM GENERATOR OR BOILER

STEAM TURBINE

ELECTRIC GENERATOR

• A boiler or steam generator is a device used to create steam by applying heat energy to water.

• It is a rectangular furnace about 50 ft (15 m) on a side and 130 ft (40 m) tall.

• Its walls are made of a web of high pressure steel tubes about 2.3 inches (60 mm) in diameter.

STEAM GENERATOR OR BOILER

• Pulverized coal is air-blown into the furnace from fuel nozzles at the four corners and it rapidly burns, forming a large fireball at the center.

• The thermal radiation of the fireball heats the water that circulates through the boiler tubes near the boiler perimeter.

• The water circulation rate in the boiler is three to four times the through output and is typically driven by pumps.

• As the water in the boiler circulates it absorbs heat and changes into steam at 700°F or 370°C.

• It is separated from the water inside a drum at the top of the furnace.

• The saturated steam is introduced into superheat pendant tubes.

• Here the steam is superheated to 1,000 °F or 540 °C to prepare it for the turbine.

STEAM TURBINE• Steam turbines are used to drive the generators, which produce

electricity.

• The turbines are driven by steam generated in 'Boilers' or 'Steam Generators’.

• Energy in the steam after it leaves the boiler is converted into rotational energy as it passes through the turbine.

• Stationary blades convert the potential energy of the steam (temperature and pressure) into kinetic energy (velocity) and direct the flow onto the rotating blades.

• The rotating blades convert the kinetic energy into forces, caused by pressure drop, which results in the rotation of the turbine shaft.

• The turbine shaft is connected to a generator, which produces the electrical energy.

• The rotational speed is 3000 rpm.

ELECTRIC GENERATOR• The generators are used to convert mechanical power, delivered

from the shaft of the turbine, into electrical power.• The mechanical energy from the turbine is converted by means a

rotating magnetic field produced by direct current in the copper winding of the rotor or field, which generates three-phase alternating currents and voltages in the copper winding of the stator (armature).

• The stator winding is connected to terminals, which are in turn connected to the power system for delivery of the output power to the system.

Rating of 95 MW Generator Capacity - 117500 KVAVoltage - 10500VSpeed - 3000 rpmHydrogen - 2.5 Kg/cm2 Power factor - 0.85 (lagging)Stator current - 6475 AFrequency - 50 Hz Stator wdg connection - 3 phase Insulation class – B

Rating of 210 MW GeneratorCapacity - 247000 KVAVoltage (stator) - 15750 VCurrent (stator) - 9050 AVoltage (rotor) - 310 VCurrent (rotor) - 2600 VSpeed - 3000 rpmPower factor - 0.85Frequency - 50 HzHydrogen - 3.5 Kg/cm2Stator wdg connection - 3 phase star connectionInsulation class - B

GENERATORS AT BTPC

ASH HANDLING

FLY ASH COLLECTION Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bag filters (or sometimes both) located at the outlet of the furnace and before the induced draft fan. The fly ash is periodically removed from the collection hoppers below the precipitators or bag filters. Generally, the fly ash is pneumatically transported to storage silos for subsequent transport by trucks or railroad cars.

BOTTOM ASH COLLECTION AND DISPOSALAt the bottom of every boiler, a hopper has been provided for collection of the bottom ash from the bottom of the furnace. This hopper is always filled with water to quench the ash and clinkers falling down from the furnace. Some arrangement is included to crush the clinkers and for conveying the crushed clinkers and bottom ash to a storage site.

SWITCHGEAR

The term switchgear, used in association with the electric power system, or grid, refers to the combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment.

Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream.

•Low Tension (less than 440 volts AC)• High Tension (more than 6.6 kV AC)

TRANSFORMERS• Step-Up the Voltage from

o 10.5kV to 220kV for 95 MW Generators.o 15.75kV to 220kV for 210MW Generators.

• 220kV output is transmitted to the switchyard for further transmission.

• Specifications :o Core typeo Lap windingo star-delta connectiono Cooling is oil natural air forced (ONAF)

SWITCH YARD

It refers to an electrical switchyard which is where high voltage electricity is switched. Electrical switchyards are usually part of a substation where electricity is transformed from one voltage to another.

The three phase power coming from transformer reaches the outgoing line by passing through isolator ,circuit breaker ,potential transformer ,current transformer and then finally to the outgoing line to different regions.