NATIONAL THERMAL POWER CORPORATIONBADARPURINDUSTRIAL TRAININGADITYA SHEKHARB.TECH 4th YEAR (ELECTRICAL AND ELECTRONICS ENGINEERING),VIET

INTRODUCTION

NTPC Limited is the largest thermal power generating company of India. A 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 shares of the company and the balance 10.5% is held by FIIs, Domestic Banks, Public and other. Within a span of 32 years, NTPC has emerged as a truly national power company, with power generating facilities in all the major regions of the country.

BACKGROUND  BADARPUR THERMAL POWER STATION was established on 1973 and it was the part of Central

Government.

On 01/04/1978 is was given to NTPC.

Since then operating performance of NTPC has been considerably above the national average.

Badarpur thermal power station started with a single 95 mw unit.

There were 2 more units (95 MW each) installed in next 2 consecutive years.

Now it has total five units with total capacity of 720 MW. Ownership of BTPS was transferred to NTPC with effect from 01.06.2006

The power is supplied to a 220 KV network that is a part of the northern grid.

The ten circuits through which the power is evacuated from the plant are:

o 1. Mehrauli

o 2. Okhla

o 3. Ballabgarh

o 4. Indraprastha

o 5. UP (Noida)

o 6. Jaipur

Installed Capacity

PRINCIPLE OF STEAM POWER PLANT GENERATION

The working principle of a steam plant is based upon the

Rankine cycle. Generally steam is taken as the working

medium due to its ability to be stable and that it’s readily stable.

The flow of steam in the plant can be very easily be understood

by the flow diagram of the plant. A graph plotted between the

temperature and the entropy would indicate the technical

details of the working by the Rankine cycle.

Plant Flow Diagram(Modified Rankine Cycle)

AB- Heating of feed water (i.e. sensible heat addition)

BC- Evaporation of water in boiler (i.e. latent heat addition)

CD- Superheating of steam (i.e. heat addition)

DE- Isentropic expansion of steam in HP turbine

EF- Reheating of steam in Reheaters

FH- Isentropic expansion of steam in IP and LP turbine

VARIOUS IMPORTANT PARTS OF BTPS1.BOILER2.TURBINES3.COOLING WATER PUMP4.CONDENSER5.DEAREATOR6.REHEATER7.AIR PREHEATER8.PRECIPITATOR9.ECONOMISER10.COOLING TOWER11.TRANSMISSION LINES(3PHASE)12.UNIT TRANSFORMERS(3 PHASE)13.ELECTRIC GENERATORS(3 PHASE)14.CONDENSATE EXTRACTION PUMP

15. Steam governor valve 16. FEED HEATER17.COAL CONVEYOR18.COAL HOPPER19.FORCED DRAUGHT FAN20.FLUE GAS

1.BoilerBoiler is a rectangular furnace about 50 feet on side and 130 feet tall. theirs walls are made of high pressure steel tubes about 2.3 inches in diameter which circulates DM water to be converted into steam. The thermal radiation heats water and changes to steam. Steam is sent to the turbine .The efficiency and technology of boiler vary according to the operational pressures.1. Operational pressure>221 KSC---

%n=42.45%-----super critical boiler2. 175KSC <Operational pressure<221

KSC---%n=38.42%----- critical boiler3. Operational pressure<175KSC---

%n=38%-----sub critical boiler

The turbine generator consists of a series of steam turbines interconnected to each other and generators on a common shaft.

2.Turbines

3.Cooling water pumpsIt pumps the water from the cooling tower which goes to the condenser.

4.CondenserThe steam coming out from the Low Pressure Turbine (a little above its boiling pump) is brought into thermal contact with cold water (pumped in from the cooling tower) in the condenser, where it condenses rapidly back into water, creating near Vacuum-like conditions inside the condenser chest.

5.Deareator

A deareator is a device for air removal and used to remove dissolved gases (an alternate would be the use of water treatment chemicals) from boiler feed water to make it noncorrosive.

6.ReheaterReheater is a heater which is used to raise the temperature of steam which has fallen from the intermediate pressure turbine.

7.Air preheaterThe purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas.

8.PrecipitatorAn Electrostatic precipitator (ESP) is a particulate device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge.

ELECTRICAL MAINTENANCE DEPARTMENT – I (EMD-I)

It includes: Motors High Tension/Low Tension Switchgear Coal handling plant

MOTORSAC MOTORS

Squirrel cage motor Wound motor Slip ring induction motor

 In modern thermal power plant three phase squirrel cage induction motors are used but sometime double wound motor is used when we need high starting torque e.g. in ball mill. 

SWITCH GEAR Switchgear is one that makes or breaks the electrical

circuit. It is a switching device that opens & closes a circuit

that defined as apparatus used for switching, Lon rolling & protecting the electrical circuit & equipments.

The switchgear equipment is essentially concerned with switching & interrupting currents either under normal or abnormal operating conditions.

The tubular switch with ordinary fuse is simplest form of switchgear & is used to control & protect& other equipments in homes, offices etc.

For circuits of higher ratings, a High Rupturing Capacity (H.R.C) fuse in condition with a switch may serve the purpose of controlling & protecting the circuit.

COAL HANDLINGThe fuel used in the thermal power plants in the boiler

furnace is coal. Coal undergoes various processes like separation, crushing, etc and is then finally moved to the furnace in the form of pulverised coal.

Coal: It is a mixture of organic chemicals and mineral materials produced by natural process of growth and decay. The chemical properties of any coal depend upon the proportions of different chemicals components present in it. There are four types of coal:

1. Peat 2. Lignite 3. Bituminous Coal 4. Anthracite

ELECTRICAL MAINTENANCE DEPARTMENT –II (EMD-II)

It includes: Generators Transformers Switch yard

GENERATORS

The generator works on the principle of electromagnetic induction. There are two components stator and rotor. The rotor is the moving part and the stator is the stationary part. The rotor, which has a field winding, is given a excitation through a set of 3000rpm to give the required frequency of HZ. The rotor is cooled by Hydrogen gas, which is locally manufactured by the plant and has high heat carrying capacity of low density. If oxygen and hydrogen get mixed then they will form very high explosive and to prevent their combining in any way there is seal oil system. The stator cooling is done by de-mineralized (DM) water through hollow conductors. Water is fed by one end by Teflon tube. A boiler and a turbine are coupled to electric generators. Steam from the boiler is fed to the turbine through the connecting pipe. Steam drives the turbine rotor. The turbine rotor drives the generator rotor which turns the electromagnet within the coil of wire conductors.

Carbon dioxide is provided from the top and oil is provided from bottom to the generator. With the help of carbon dioxide the oil is drained out to the oil tank.

RATINGS OF THE GENERATORS USED

Turbo generator 100MW TURBO GENERATOR 210 MW  The 100 MW generator generates 10.75 KV and 210 MW

generates 15.75 KV. The voltage is stepped up to 220 KV with the help of generator transformer and is connected to the grid.

The voltage is stepped down to 6.6 KV with the help of UNIT AUXILLARY TRANSFORMER (UAT) and this voltage is used to drive the HT motors. The voltage is further stepped down to 415 V and then to 220 V and this voltage is used to drive Lt Motors.

 

TRANSFORMERS

It is a static machine which increases or decreases the AC voltage without changing the frequency of the supply.

It is a device that: Transfer electric power from one circuit to another. It accomplishes this by electromagnetic induction. In this the two electric circuits are in mutual inductive

influence of each other.

WORKING PRINCIPLE:It works on FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION (self or mutual induction depending on the type of transformer).

MAIN PARTS OF TRANSFORMER 1. Secondary Winding2. Primary Winding.3. Oil Level4. Conservator5. Breather6. Drain Cock7. Cooling Tubes.8. Transformer Oil.9. Earth Point10. Explosion Vent 11. Temperature Gauge.12. Buchholz Relay13. Secondary Terminal14. Primary Terminal

SWITCH YARD As we know that electrical energy can’t be stored like cells, so what we generate should be consumed instantaneously. But as the load is not constants therefore we generate electricity according to need i.e. the generation depends upon load. The yard is the places from where the electricity is send outside. It has both outdoor and indoor equipments. OUTDOOR EQUIPMENTS

BUS BAR. LIGHTENING ARRESTER WAVE TRAP BREAKER CAPACITATIVE VOLTAGE TRANSFORMER EARTHING ROD CURRENT TRANSFORMER. POTENTIAL TRANSFORMER LIGHTENING MASK 

INDOOR EQUIPMENTS

RELAYS. CONTROL PANELS CIRCUIT BREAKERS

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