1. BHARAT HEAVY ELECTRICALS
LIMITED
ELECTRONICS DIVISION
A Report on
Power Plant Station,Automation & Control
Systems

2. Introduction to BHEL
BHEL Electronics Division (EDN) along with Electronics Systems Division (ESD-part of EDN), situated at
Bangalore is a leading supplier of new Generation Power Plant Automation and Control Systems. The
Electronics Division has also emerged as a leading player in the field of power transmission and distribution,
industry, transportation and non-conventional energy sources. The state-of-the-art equipment and systems
manufactured, meet the demanding requirements of both the national and international markets in terms of
technical specification and quality.
The Division has established references both in India and overseas by successful installation of Power
PlantAutomation and Photovoltaic systems. Besides providing unified solutions for various control system
applications, the Division proudly holds the largest market share for Power Plant Automation systems in India.
BHEL At Present
 Power Plant and Industries: Advance control and automation equipment and systems for power plants and
process industries
 Transmission and Distribution: Providing solutions for improving the efficiency, quality of power and
system stability
 Transportation: IGBT based Traction Drive Systems for Locomotives
 Non-conventional energy: Photovoltaic cells, Modules, MW size Power Plants, Space Grade Solar
Panels, Space Batteries and provide system level solutions
Product excellence, commitment to Quality, relentless efforts and unwavering commitment to in-house
solutions, along with Technical collaborations with international leaders, strategic investment in new ultra-
modern facilities and capacity expansion, have been the main factors for the rapid growth of the Division.
Certifications
ISO 9001 : Quality systems and procedures
ISO 14001: Environmental Management System Certification
ISO 27001: Information Security Management System(ISMS) Standard
OHSAS 18001: Occupational Health and Safety Assessment Series
Vision
BHEL’s vision envisages further growth for EDN, transforming the unit into a world class enterprise, providing
comprehensive solutions to customers, while exploring new frontiers in software and hardware applications to
fulfil the growing needs and expectations of the global market.
The Company has also joined the United Nations “Global Compact” and has committed to support the set of core
values enshrined in its principles in the area of human rights, labour standards, environment and anti-corruption.

3. EDN – Product Panorama
 THERMAL POWER PLANTS
Steam Generators, Steam Turbines, Turbo Generators along with regenerative feed cycle up to 800 MW
capacities for fossil-fuel, and combined-cycle applications, capability to design and manufacture Steam
Generators, steam turbines with supercritical steam cycle parameters and matching Turbo Generators of up to
1000 MW unit size.
Condensers, Condensate Extraction Pumps, Boiler Feed Pumps, Valves and Heat Exchangers meeting above
requirement of TG Sets up to 1000 MW.
 NUCLEAR POWER PLANTS
Steam generator & Turbines and matching Turbo-Generators, Condensers up to 700 MW capacity.
Heat exchangers
Pressure vessel
Reactor vessels
 GAS-BASED POWER PLANTS
Gas turbines and matching generators ranging from 25 to 292 MW (ISO) rating.
Gas turbine-based co-generation and combined-cycle systems for industry and utility applications.
 BOILERS
Steam generators for utilities, ranging from 30 to 800 MW capacity, using coal, lignite, oil, natural gas or a
combination of these fuels; capability to manufacture boilers with supercritical parameters up to 1000 MW unit
size.
Steam generators for industrial applications, ranging from 40 to 450 tonne/hour capacity, using coal, natural gas,
industrial gases, biomass, lignite, oil, Bagasse or a combination of these fuels.
Pulverized fuel fired boilers
Stoker boilers
Bubbling fluidized bed combustion (BFBC) boilers.
Circulating fluidized bed combustion (CFBC) boilers up to 250 MW.
Heat-recovery steam generators (HRSG).
Chemical recovery boilers for paper industry, ranging from capacity of 100 to 1000 tonne/day of dry solids.
 CONDENSER AND HEAT EXCHANGERS
Surface Condenser:
236 MW & 700 MW for Nuclear power plants
12.5 MW Marine applications
Industrial Condensers
Feed Water Heaters (HP Heaters, LP Heaters, Drain Coolers etc.)
Thermal -07 to 500 MW (sub-critical) & 300-800 MW (super critical with single stream)
Nuclear 236 MW, 500 MW and 700 MW rating
Moisture Separator &Reheater(MSR):
236 MW, 500 MW & 700 MW Nuclear sets
Live Steam Reheater (LSR):
500 MW FBR Nuclear sets
Auxiliary Heat Exchangers for Turbo and Hydro Generators :
Air Coolers (Frame & Tube Type)
Oil Coolers (Shell & Tube Type and Plug In Type)

4. Hydrogen Coolers (Frame & Tube Type)
Auxiliary Heat Exchangers for Transformers :
Oil Coolers (Shell & Tube Type Single Tube or Concentric Double Tube Type) (Frame & Tube Type)
Auxiliary Heat Exchangers for General Application
Water - Water Coolers (Shell & Tube Type)
Industrial Heat Exchangers for Refineries, Petro-Chemicals & Fertilizers industries.
Butterfly Valves( Fabricated/ cast body & door)
Flash Tanks for thermal & nuclear sets
Service Tanks, Storage Tanks & Pressure vessels for Thermal, Nuclear sets of all ratings & industrial
applications
CS/SS/Non-ferrous shell and tube heat exchangers and pressure vessels (For all applications irrespective of
rating)
Air-cooled heat exchangers for GTG upto Fr-9 FE, and Compressor applications of all ratings
Steam jet air ejectors for all condensers upto 150 MW
Deaerators from 7 MW to 800 MW
Gland steam condensers 7 MW to 150 MW
Gas coolers for all possible compressor applications
Oil coolers- STG upto 150 MW, GTG upto Fr-9 F E,
Generator Air coolers upto 150 MW STG and GTG up to 9 FA
 PUMPS
Pumps for various applications to suit utilities up to a capacity of 1000 MW.
Boiler feed pumps (motor or steam turbine driven).
Boiler feed booster pumps.
Condensate extraction pumps.
Circulating water pumps. (Also known as-Cooling water Pumps)
 AUTOMATION AND CONTROL SYSTEMS
Steam Generator/ Boiler Controls
Steam Turbine Controls
Boiler Feed Pump (BFP) Drive Turbine Control
Station Control and Instrumentation/ DCS
Offsite/Off base controls/ Balance of Plant Controls
Ash handling
Coal Handling
Water System
Mill Reject System
Condensate on-line tube cleaning system
Gas Booster Compressor
Hydro Power Plant Control System
Gas Turbine Control System
Nuclear Power Plant Turbine & Secondary Cycle control system
Power block of solar thermal power plant
Industrial Automation
Sub-Station Automation (SAS) and Supervisory Control & data Acquisition System (SCADA)
Electrical Control System (ECS) for Refineries
Energy Management System (EMS) for Power Plant

5.  POWER ELECTRONICS
Excitation system
AC Drive System
Static Starters
Induction Heating Equipment
 TRANSMISSION SYSTEM CONTROL
High Voltage Direct Current (HVDC) system
Flexible AC Transmission system (FACTS)
Fixed series compensation (FCS)/ Thyristor controlled series compensation (TCSC)
Static VAR Compensation (SVC) System
Controlled Shunt Reactor (CSR)
Static Compensator (STATCOM)
 POWER SEMICONDUCTOR DEVICES
Diodes- Ranging from 1400-4400V/250-2000A
Thyristors- Ranging from 1400-7000V/150-4950A
Rotating Diodes for Turbo generators.
 SOLAR PHOTOVOLTAICS
Mono/ Multi Crystalline Cells (125 and 156 mm)
Mono/ Multi Crystalline Modules (40 to 300 Wp)
PV Systems: Grid Interactive, Hybrid and stand alone PV power plants
Space grade solar panels
Space Quality Batteries
 DEFENCE ELECTRONICS
Integrated Platform Management system (IPMS)
Integrated Bridge System (IBS)
Machinery Control Room (MCR) Simulator
Training Simulator for Vehicles, platforms, radars, weapons, missiles and CBT for all defence and para-military
forces
Weapon Fire control system, Avionics, radio communication Products, Electronic warfare system and Early
Warning Systems.
Gun control System for Main Battle Tanks (MBT)

6. Thermal PowerPlant Layout
At present 54.09% or 93918.38 MW (Data Source CEA, as on 31/03/2011) of total electricity production in India
is from Coal Based Thermal Power Station. A coal based thermal power plant converts the chemical energy of
the coal into electrical energy. This is achieved by raising the steam in the boilers, expanding it through the
turbine and coupling the turbines to the generators which converts mechanical energy into electrical energy.
A typical Thermal Power Station Operates on a Cycle which is shown below.
A thermal power station is a power plant in which the prime mover is steam driven. Water is heated, turns into
steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the
steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle. The
greatest variation in the design of thermal power stations is due to the different fossil fuel resources generally
used to heat the water. Some prefer to use the term energy centre because such facilities convert forms of
heatenergy into electrical energy. Certain thermal power plants also are designed to produce heat power.
Globally, fossil-fuel power stations produce a large part of man-made CO2 emissions to the atmosphere, and
efforts to reduce these are varied and widespread.

7. Theory of Thermal PowerPlant Station
The theory of thermal power station or working of thermal power station is very simple. A power generation
plant mainly consists of alternator runs with help of steam turbine. The steam is obtained from high pressure
boilers. Generally in India, bituminous coal, brown coal and peat are used as fuel of boiler. The bituminous coal
is used as boiler fuel has volatile matter from 8 to 33 % and ash content 5 to 16 %. To increase the thermal
efficiency, the coal is used in the boiler in powder form.
In coal thermal power plant, the steam is produced in high pressure in the steam boiler due to burning of fuel
(pulverized coal) in boiler furnaces. This steam is further supper heated in a super heater. This supper heated
steam then enters into the turbine and rotates the turbine blades. The turbine is mechanically so coupled with
alternator that its rotor will rotate with the rotation of turbine blades. After entering in turbine the steam pressure
suddenly falls and corresponding volume of the steam increases. After imparting energy to the turbine rotor the
steam passes out of the turbine blades into the condenser. In the condenser the cold water is circulated with the
help of pump which condenses the low pressure wet steam. This condensed water is further supplied to low
pressure water heater where the low pressure steam increases the temperature of this feed water, it is again heated
in high pressure.
For better understanding we furnish every step of function of a thermal power station as follows,
1) First the pulverized coal is burnt into the furnace of steam boiler.
2) High pressure steam is produced in the boiler.
3) This steam is then passed through the super heater, where it further heated up.
4) This supper heated steam is then entered into a turbine at high speed.
5) In turbine this steam force rotates the turbine blades that means here in the turbine the stored potential energy
of the high pressured steam is converted into mechanical energy.
6) After rotating the turbine blades, the steam has lost its high pressure, passes out of turbine blades and enters
into a condenser.
7) In the condenser the cold water is circulated with help of pump which condenses the low pressure wet steam.
8) This condensed water is then further supplied to low pressure water heater where the low pressure steam
increases the temperature of this feed water, it is then again heated in a high pressure heater where the high
pressure of steam is used for heating.
9) The turbine in thermal power station acts as a prime mover of the alternator.
Components of Thermal PowerPlantStation
 Coal Preparation
 Steam Generator/Boiler
 Boiler drum
 Steam Turbines
 Condenser
 Boiler Feed Pump
 Cooling Towers
 Generator
 Electrostatic Precipitator

8.  Smoke stack
 CoalPreparation
 Fuel preparation system: In coal-fired power stations, the raw feed coal from the coal storage area 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, so that coal will undergo complete combustion during combustion
process
 Pulveriser pulveriser is a mechanical device for the grinding of many different types of materials. For
example, they are used to pulverize coal for combustion in the steam-generating furnaces of fossil fuel
power plants. Types of Pulverisers: Ball and Tube mills; Ring and Ball mills; MPS; Ball mill; Demolition
 Dryers: they are used in order to remove the excess moisture from coal mainly wetted during transport.
As the presence of moisture will result in fall in efficiency due to incomplete combustion and also result
in CO emission.
 Magnetic separators: coal which is brought may contain iron particles. These iron particles may result in
wear and tear. The iron particles may include bolts, nuts wire fish plates etc. so these are unwanted and so
are removed with the help of magnetic separators.
The coal we finally get after these above process are transferred to the storage site.
Purpose of fuel storage is two –
 Fuel storage is insurance from failure of normal operating supplies to arrive.
 Storage permits some choice of the date of purchase, allowing the purchaser to take advantage of seasonal
market conditions. Storage of coal is primarily a matter of protection against the coal strikes, failure of
the transportation system & general coal shortages.
There are two types of storage:
1. Live Storage (boiler room storage): storage from which coal may be withdrawn to supply combustion
equipment with little or no remanding is live storage. This storage consists of about 24 to 30 hrs. of coal
requirements of the plant and is usually a covered storage in the plant near the boiler furnace. The live
storage can be provided with bunkers & coal bins. Bunkers are enough capacity to store the requisite of
coal. From bunkers coal is transferred to the boiler grates.
2. Dead storage– stored for future use. Mainly it is for longer period of time, and it is also mandatory to
keep a backup of fuel for specified amount of days depending on the reputation of the company and its
connectivity.There are many forms of storage some of which are –
1. Stacking the coal in heaps over available open ground areas.
2. As in (I). But placed under cover or alternatively in bunkers.
3. Allocating special areas & surrounding these with high reinforced concerted retaking walls.
 Feedwaterheating
The boiler feed water used in the steam boiler is a means of transferring heat energy from the burning fuel
to the mechanical energy of the spinning steam turbine. The total feed water consists of recirculated
condensate water and purified makeup water. Because the metallic materials it contacts are subject to
corrosion at high temperatures and pressures, the makeup water is highly purified before use. A system of
water softeners and ion exchange demineralizers produces water so pure that it coincidentally becomes an
electrical insulator, with conductivity in the range of 0.3–1.0 micro Siemens per centimetre. The makeup
water in a 500 MW plant amounts to perhaps 120 US gallons per minute (7.6 L/s)to replace water drawn
off from the boiler drums for water purity management, and to also offset the small losses from steam
leaks in the system.
 Boilerand Auxiliaries
The boiler is a rectangular furnace about 50 feet (15 m) on a side and 130 feet (40 m) tall. Its walls are made of a
web of high pressure steel tubes about 2.3 inches (58 mm) in diameter.

9. Pulverized coal is air-blown into the furnace through burners located at the four corners, or along one wall, or
two opposite walls, and it is ignited to rapidly burn, forming a large fireball at the centre. The thermal radiationof
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 throughput. As the water in the boiler circulates it absorbs heat and
changes into steam. It is separated from the water inside a drum at the top of the furnace. The saturated steam is
introduced into superheat pendant tubes that hang in the hottest part of the combustion gases as they exit the
furnace. Here the steam is superheated to 1,000 °F (540 °C) to prepare it for the turbine.
 Boiler furnace and steam drum
The water enters the boiler through a section in the convection pass called the economizer. From the economizer
it passes to the steam drum and from there it goes through down comers to inlet headers at the bottom of the
water walls. From these headers the water rises through the water walls of the furnace where some of it is turned
into steam and the mixture of water and steam then re-enters the steam drum. This process may be driven purely
by natural circulation (because the water is the down comers is denser than the water/steam mixture in the water
walls) or assisted by pumps. In the steam drum, the water is returned to the down comers and the steam is passed
through a series of steam separators and dryers that remove water droplets from the steam. The dry steam then
flows into the superheater coils.
The boiler furnace auxiliary equipment includes coal feed nozzles and igniter guns, soot blowers, water lancing
and observation ports (in the furnace walls) for observation of the furnace interior. Furnace explosions due to any
accumulation of combustible gases after a trip-out are avoided by flushing out such gases from the combustion
zone before igniting the coal.
The steam drum (as well as the super heater coils and headers) have air vents and drains needed for initial start-
up
 Superheater
Fossil fuel power plants often have a superheater section in the steam generating furnace. The steam passes
through drying equipment inside the steam drum on to the superheater, a set of tubes in the furnace. Here the
steam picks up more energy from hot flue gases outside the tubing and its temperature is now superheated above

10. the saturation temperature. The superheated steam is then piped through the main steam lines to the valves before
the high pressure turbine.
The amount of superheat added to the steam is influenced by the location, arrangement, and amount of
superheater surface installed, as well as the rating of the boiler. The superheater may consist of one or more
stages of tube banks arranged to effectively transfer heat from the products of combustion.Superheaters are
classified as convection, radiant or combination of these.
 Economizer
It is located below the LPSH in the boiler and above pre heater. It is there to improve the efficiency of boiler by
extracting heat from flue gases to heat water and send it to boiler drum.
Flue gases coming out of the boiler carry lot of heat.Function of economiser is to recover some of the heat from
the heat carried away in the flue gases up the chimney and utilize for heating the feed water to the boiler.It is
placed in the passage of flue gases in between the exit from the boiler and the entry to the chimney.The use of
economiser results in saving in coal consumption , increase in steaming rate and high boiler efficiency but needs
extra investment and increase in maintenance costs and floor area required for the plant.This is used in all
modern plants.In this a large number of small diameter thin walled tubes are placed between two headers.Feed
water enters the tube through one header and leaves through the other.The flue gases flow outside the tubes
usually in counter flow.
Advantages of Economizer include
1) Fuel economy: – used to save fuel and increase overall efficiency of boiler plant.
2) Reducing size of boiler: – as the feed water is preheated in the economiser and enter boiler tube at elevated
temperature. The heat transfer area required for evaporation reduced considerably.
 Air Preheater
The remaining heat of flue gases is utilised by air preheater.It is a device used in steam boilers to transfer heat
from the flue gases to the combustion air before the air enters the furnace. Also known as air heater; air-heating
system. It is not shown in the lay out.But it is kept at a place near by where the air enters in to the boiler.
The purpose of the air preheater is to recover the heat from the flue gas from the boiler to improve boiler
efficiency by burning warm air which increases combustion efficiency, and reducing useful heat lost from the
flue. As a consequence, the gases are also sent to the chimney or stack at a lower temperature, allowing
simplified design of the ducting and stack. It also allows control over the temperature of gases leaving the stack
(to meet emissions regulations, for example).After extracting heat flue gases are passed to electrostatic
precipitator.
 Reheater
Power plant furnaces may have a reheater section containing tubes heated by hot flue gases outside the tubes.
Exhaust steam from the high pressure turbine is rerouted to go inside the reheater tubes to pick up more energy to
go drive intermediate or lower pressure turbines.
 Air path
External fans are provided to give sufficient air for combustion. The Primary air fan takes air from the
atmosphere and, first warming it in the air preheater for better combustion, injects it via the air nozzles on the
furnace wall.
The induced draft fan assists the FD fan by drawing out combustible gases from the furnace, maintaining a
slightly negative pressure in the furnace to avoid backfiring through any closing.

11.  SteamTurbines
The turbine generator consists of a series of steam turbines interconnected to each other and a generator on a
common shaft. There is a high pressure turbine at one end, followed by an intermediate pressure turbine, two low
pressure turbines, and the generator. As steam moves through the system and loses pressure and thermal energy it
expands in volume, requiring increasing diameter and longer blades at each succeeding stage to extract the
remaining energy. The entire rotating mass may be over 200 metric tons and 100 feet (30 m) long. It is so heavy
that it must be kept turning slowly even when shut down (at 3 rpm) so that the shaft will not bow even slightly
and become unbalanced. This is so important that it is one of only five functions of blackout emergency power
batteries on site. Other functions are emergency lighting, communication, station alarms and turbo generator lube
oil.
Superheated steam from the boiler is delivered through 14–16-inch (360–410 mm) diameter piping to the high
pressure turbine where it falls in pressure to 600 psi (4.1 MPa) and to 600 °F (320 °C) in temperature through the
stage. It exits via 24–26-inch (610–660 mm) diameter cold reheat lines and passes back into the boiler where the
steam is reheated in special reheat pendant tubes back to 1,000 °F (540 °C). The hot reheat steam is conducted to
the intermediate pressure turbine where it falls in both temperature and pressure and exits directly to the long-
bladed low pressure turbines and finally exits to the condenser.
The generator, 30 feet (9 m) long and 12 feet (3.7 m) in diameter, contains a stationary stator and a spinning
rotor, each containing miles of heavy copper conductor—no permanent magnets here. In operation it generates
up to 21,000 amperes at 24,000 voltsAC (504 MWe) as it spins at either 3,000 or 3,600 rpm, synchronized to the
power grid. The rotor spins in a sealed chamber cooled with hydrogen gas, selected because it has the highest
known heat transfer coefficient of any gas and for its low viscosity which reduces windage losses. This system
requires special handling during start-up, with air in the chamber first displaced by carbon dioxide before filling
with hydrogen. This ensures that the highly explosive hydrogen–oxygen environment is not created.
The power grid frequency is 60 Hz across North America and 50 Hz in Europe, Oceania, Asia (Korea and parts
of Japan are notable exceptions) and parts of Africa. The desired frequency affects the design of large turbines,
since they are highly optimized for one particular speed.
The electricity flows to a distribution yard where transformers increase the voltage for transmission to its
destination.
The steam turbine-driven generators have auxiliary systems enabling them to work satisfactorily and safely. The
steam turbine generator being rotating equipment generally has a heavy, large diameter shaft. The shaft therefore
requires not only supports but also has to be kept in position while running. To minimize the frictional resistance
to the rotation, the shaft has a number of bearings. The bearing shells, in which the shaft rotates, are lined with a
low friction material like Babbitt metal. Oil lubrication is provided to further reduce the friction between shaft
and bearing surface and to limit the heat generated.

12.  Condenser
Steam after rotating steam turbine comes to condenser.Condenser refers here to the shell and tube heat exchanger
(or surface condenser) installed at the outlet of every steam turbine in Thermal power stations of utility
companies generally. These condensers are heat exchangers which convert steam from its gaseous to its liquid
state, also known as phase transition. In so doing, the latent heat of steam is given out inside the condenser.
Where water is in short supply an air cooled condenser is often used. An air cooled condenser is however
significantly more expensive and cannot achieve as low a steam turbine backpressure (and therefore less
efficient) as a surface condenser.
The purpose is to condense the outlet (or exhaust) steam from steam turbine to obtain maximum efficiency and
also to get the condensed steam in the form of pure water, otherwise known as condensate, back to steam
generator or (boiler) as boiler feed water.
Condensers are classified as
I. Jet condensers or contact condensers
II. Surface condensers
In jet condensers the steam to be condensed mixes with the cooling water and the temperature of the condensate
and the cooling water is same when leaving the condenser; and the condensate can't be recovered for use as feed
water to the boiler; heat transfer is by direct conduction.
In surface condensers there is no direct contact between the steam to be condensed and the circulating cooling
water. There is a wall interposed between them through heat must be convectively transferred.The temperature of
the condensate may be higher than the temperature of the cooling water at outlet and the condensate is recovered
as feed water to the boiler.Both the cooling water and the condensate are separately with drawn.Because of this
advantage surface condensers are used in thermal power plants.Final output of condenser is water at low
temperature is passed to high pressure feed water heater,it is heated and again passed as feed water to the
boiler.Since we are passing water at high temperature as feed water the temperature inside the boiler does not
decrease and boiler efficiency also maintained.
 Boilerfeed Pump
Boiler feed pump is a multi-stage pump provided for pumping feed water to economiser. BFP is the biggest
auxiliary equipment after Boiler and Turbine. It consumes about 4 to 5 % of total electricity generation.

13.  Cooling Towers
The condensate (water) formed in the condenser after condensation is initially at high temperature.This hot water
is passed to cooling towers.It is a tower- or building-like device in which atmospheric air (the heat receiver)
circulates in direct or indirect contact with warmer water (the heat source) and the water is thereby cooled (see
illustration). A cooling tower may serve as the heat sink in a conventional thermodynamic process, such as
refrigeration or steam power generation, and when it is convenient or desirable to make final heat rejection to
atmospheric air. Water, acting as the heat-transfer fluid, gives up heat to atmospheric air, and thus cooled, is
recirculated through the system, affording economical operation of the process.
Two basic types of cooling towers are commonly used. One transfers the heat from warmer water to cooler air
mainly by an evaporation heat-transfer process and is known as the evaporative or wet cooling tower.
Evaporative cooling towers are classified according to the means employed for producing air circulation through
them:atmospheric, natural draft, and mechanical draft. The other transfers the heat from warmer water to cooler
air by a sensible heat-transfer process and is known as the non-evaporative or dry cooling tower.
Non-evaporative cooling towers are classified as air-cooled condensers and as air-cooled heat exchangers, and
are further classified by the means used for producing air circulation through them. These two basic types are
sometimes combined, with the two cooling processes generally used in parallel or separately, and are then known
as wet-dry cooling towers.
Evaluation of cooling tower performance is based on cooling of a specified quantity of water through a given
range and to a specified temperature approach to the wet-bulb or dry-bulb temperature for which the tower is
designed. Because exact design conditions are rarely experienced in operation, estimated performance curves are
frequently prepared for a specific installation, and provide a means for comparing the measured performance
with design conditions.
 Generator
Generator or Alternator is the electrical end of a turbo-generator set. It is generally known as the piece of
equipment that converts the mechanical energy of turbine into electricity. The generation of electricity is based
on the principle of electromagnetic induction. Most alternators use a rotating magnetic field. Different
geometries - such as a linear alternator for use with stirling engines - are also occasionally used. In principle, any
AC generator can be called an alternator, but usually the word refers to small rotating machines driven by
automotive and other internal combustion engines.
The generator voltage for modern utility-connected generators ranges from 11 kV in smaller units to 22 kV in
larger units. The generator high-voltage leads are normally large aluminium channels because of their high
current as compared to the cables used in smaller machines.
They are enclosed in well-grounded aluminium bus ducts and are supported on suitable insulators. The generator
high-voltage leads are connected to step-up transformers for connecting to a high-voltage electrical substation
(usually in the range of 115 kV to 765 kV) for further transmission by the local power grid.

14. The necessary protection and metering devices are included for the high-voltage leads. Thus, the steam turbine
generator and the transformer form one unit. Smaller units may share a common generator step-up transformer
with individual circuit breakers to connect the generators to a common bus.
 Electrostatic precipitator
It is a device which removes dust or other finely divided particles from flue gases by charging the particles
inductively with an electric field, then attracting them to highly charged collector plates. Also known as
precipitator. The process depends on two steps. In the first step the suspension passes through an electric
discharge (corona discharge) area where ionization of the gas occurs. The ions produced collide with the
suspended particles and confer on them an electric charge. The charged particles drift toward an electrode of
opposite sign and are deposited on the electrode where their electric charge is neutralized. The phenomenon
would be more correctly designated as electrodeposition from the gas phase.
The use of electrostatic precipitators has become common in numerous industrial applications. Among the
advantages of the electrostatic precipitator are its ability to handle large volumes of gas, at elevated temperatures
if necessary, with a reasonably small pressure drop, and the removal of particles in the micrometre range. Some
of the usual applications are:
(1) Removal of dirt from flue gases in steam plants;
(2) Cleaning of air to remove fungi and bacteria in establishments producing antibiotics and other drugs,
and in operating rooms;
(3) Cleaning of air in ventilation and air conditioning systems;
(4) Removal of oil mists in machine shops and acid mists in chemical process plants;
(5) Cleaning of blast furnace gases;
(6) Recovery of valuable materials such as oxides of copper, lead, and tin; and
(7) Separation of rutile from zirconium sand.
 Smoke stack
A chimney is a system for venting hot flue gasesor smoke from a boiler, stove, furnace or fireplace to the
outsideatmosphere. They are typically almost vertical to ensure that the hot gases flow smoothly, drawing air
into the combustion through the chimney effect (also known as the stack effect). The space inside a chimney
is called a flue. Chimneys may be found in buildings, steam locomotives and ships. The term funnel is
generally used for ship chimneys and sometimes used to refer to locomotive chimneys.Chimneys are tall to
increase their draw of air for combustion and to disperse pollutants in the flue gases over a greater area so as
to reduce the pollutant concentrations in compliance with regulatory or other limits.
Monitoring and alarm system
Most of the power plant operational controls are automatic. However, at times, manual intervention may be
required. Thus, the plant is provided with monitors and alarm systems that alert the plant operators when certain
operating parameters are seriously deviating from their normal range.
Battery-supplied emergencylighting and communication
A central battery system consisting of lead acid cell units is provided to supply emergency electric power, when
needed, to essential items such as the power plant's control systems, communication systems, turbine lube oil
pumps, and emergency lighting. This is essential for a safe, damage-free shutdown of the units in an emergency
situation.
Advantages of coal based thermal Power Plant
 They can respond to rapidly changing loads without difficulty
 A portion of the steam generated can be used as a process steam in different industries

15.  Steam engines and turbines can work under 25 % of overload continuously
 Fuel used is cheaper
 Cheaper in production cost in comparison with that of diesel power stations
Disadvantages of coal based thermal Power Plant
 Maintenance and operating costs are high
 Long time required for erection and putting into action
 A large quantity of water is required
 Great difficulty experienced in coal handling
 Presence of troubles due to smoke and heat in the plant
 Unavailability of good quality coal
 Maximum of heat energy lost
 Problem of ash removing
Efficiency of Thermal powerstation
The overall efficiency of a thermal power station or plant varies from 20% to 26% and it depends upon
plant capacity.
Installed plant capacity Average overall thermal efficiency
1MW 4%
1MW to 10MW 12%
10MW to 50MW 16%
50MW to 100MW 24%
above 100MW 27%
Thermal PowerPlant Location
A thermal power station or thermal power plant has ultimate target to make business profit. Hence for optimizing
the profit, the location of the station is much important factor. Power generation plant location plays an
optimizing part in the economy of the station.Many points to be considered to decide the best optimized location
of the power plant.
1) The electric power generation plant must be constructed at such a place where the cost of land is quite
reasonable.
2) The land should be such that the acquisition of private property must be minimum.
3) A large quantity of cooling water is required for the condensers etc of thermal power generation plant, hence
the plant should preferably situated beside big source of natural water source such as big river.
4) Availability of huge amount of fuel at reasonable cost is one of the major criterions for choosing plant
location.
5) The plant should be established on plane land.
6)The soil should be such that it should provide good and firm foundation of plant and buildings.
7) The thermal power plant location should not be very nearer to dense locality as there are smoke, noise steam,
water vapours etc.
8) There must be ample scope of development of future demand.

16. 9) Place for ash handling plant for thermal power station should also be available very nearby.
10) Very tall chimney of power station should not obstruct the traffics of air ships.
PowerPlant Automation
Power-system automation is the act of automatically controlling the power system via instrumentation and
control devices. Substation automation refers to using data fromIntelligent electronic devices (IED), control and
automation capabilities within the substation, and control commands from remote users to control power-system
devices.
 Automation for Hydro Power Plants/Irrigation Projects comprising of:
 Computerised control and Monitoring Systems
 Unit Control Boards
 Switchyard Control Boards
 Automatic Plant start-up/shut-down System
 Dam Controls
Typical display on HMI Work Station
 Important Achievements
 Export of Hydel Power Plant controls for project in Bhutan, Taiwan, Nepal, Vietnam, Tajikistan,
Afghanistan and Republic of Rewanda
 Excitation system has been designed, supplied and commissioned in a record time of one month to
restore the flood affected Power plant for APGENCO Srisailam 7X110 MW HEP

17. Performance Analysis, Diagnosticsand Optimisation(PADO)
BHEL-EDN offers PADO, a customized software based Performance Analysis, Diagnostics and Optimisation
Package, working on a client-server environment for Power Plants.
The PADO Package can be proposed and configured in following function-wise modules to suit project
requirements of sub-critical and super-critical utilities:
 Performance Analysis and Monitoring
 System and Performance Optimisation
 System and Performance Diagnostics
 Boiler Performance Optimisation System(BPOS) including intelligent soot blowing
 Intelligent Water and Steam Chemistry Management System
 Emission analysis and Monitoring
 Lifetime Monitoring of Boiler Thick walled components
Optimisation Package Display Screen
SolarPhotovoltaic Systems
The Electronics Division of BHEL where the Photovoltaic modules are manufactured has been involved in
the design and manufacture of sophisticated electronics and power semiconductors since 1978. Based on
this expertise, BHEL commenced manufacturing of Solar Photovoltaic cells and modules from 1983. The
Solar Cells and Solar PV Modules are manufactured in the State of the Art manufacturing line at Bangalore.
 Application
 Solar PV Power Plants
 Power packs for Banks/Retail fuel Outlets/Rural telephone Exchanges, etc.
 Water Pumping System
 Home Lighting
 Street Lighting

18. PowerSemiconductorDevices
BHEL commenced manufacture of power semiconductor devices in the year 1978, to cater to the growing
requirements of power electronic systems and controls in India. The semiconductor devices from BHEL,
consisting of thyristors, diodes and power modules, have earned a reputation for high reliability
and quality and are also exported to other countries.
These devices are manufactured in a state-of-the-art fabrication facility having diffusion, alloying,
encapsulation and testing equipment and this centre is the first in India to have been accredited with ISO
9001 and ISO 14000 certification among semiconductor product segment. BHEL-make devices are widely
used in a variety of applications such as High Current Rectifiers, UPS & Battery Chargers, Industrial &
Traction Equipment, High Speed Exciters of Turbo-generators and HVDC transmission systems.
 Diodes and Thyristors
Power Semiconductor Diodes in the range of 1400-4400V/250-2000A and Power Thyristors in the
range of 1400-7000V/150-4950A are manufactured and supplied to various market segment such as
Power Generation Transmission, Industrial Applications, Traction system etc.
EDN – Infrastructure
 Control Equipment Fabrication
 CNC Turret Punch,Turret with 45 stations, capable of handling sheets upto 2500 mm x 1250
mm with repositioning
 CNC Hydraulic Press Brake 150 T capacity
 CNC Lathe with Siemens 840D controller
CNC Turret Punch Machine Lathe with Bar Feeder

19. Control Equipment Main Assembly
 Multiple shop-floors with an aggregate area of 6900 m2 , many of them air-conditioned
 Total production capacity of about 5000 cubicles per annum
 Dedicated shop-floor with EOT crane of 5 Ton capacity for Power-convertors used in locomotives
 Automatic wire cutting, stripping and crimping machines
Main Assembly
Control Equipment System Testing
 Air-conditioned test area of approximately 2500 m2
 Capacity to line up and test upto 600 cubicles at a time across 5 test shop-floors
 Partial Discharge Test upto 50KV on HV circuits
 Sequence-of-event recording for DCS upto 128 channels
 Innovation simulation software tools and test-programs for control logic validation of DCS
Conclusion
In its quest to be a world-class Engineering Enterprise, committed to enhancing stakeholder values, BHEL
has been practicing International Standards of Quality in its products, Systems and Services through a
comprehensive Quality policy.
BHEL-EDN has always been striving to be a good cooperative citizen, striving to create environment-
friendly atmosphere through greeneries and eco-friendly business practices.
With the objective of developing young engineers from the rural belt of the country, BHEL has been
providing them with in-depth professional training.
.