APractical Training Report

On

“KOTA SUPER THERMAL POWER STATION”

Submitted in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGYIn

MECHANICAL

2010-2011(12th May, 2010 - 12th June, 2010)

Submitted To: Submitted By:

MECHNICAL ENGINEERING

CONTENTSS.NO. TOPIC REMARK

1.

2.

3.

4.

5.

PREFACE

ACKNOWLEDGEMENT

ABOUT PLANT

PLANT FAMILIARIZATION(i) TUBINE(ii) BOILER(iii) E.S.P.(iv)COAL HANDLING PLANT(v)ASH HANDLING PLANT(vi) GENERATOR(vii)(viii)

CONTROL AND INSTRUMENTATION CIRCLE

(i) SWAS PACKAGE

(ii) ATRS PACKAGE

(iii) DDC PACKAGE

(iv) FSSS PACKAGE

PREFACEA very important element in curriculum of an Engineering student is the

Practical Training.I under went practical training at “KOTA SUPER THERMAL

POWER STATION” from 11-05-2010 to 11-06-2010. This is a part of total 30 days training program incorporated in the curriculum of the RAJASTHAN TECHNICAL UNIVERSITY for B.Tech. courses. This period was before my 6th

sem. - B.Tech. Exams.

As I am a student of Mechanical Branch so the training at K.S.T.P.S. has been particularly beneficial for me. I saw the various procedures, processes and equipment used in production of electricity by thermal powers which were studied in books and this has helped me in better understanding of power generation.

S.T.P.S. is a very large plant and it is very difficult to acquire complete knowledge about it in a short span. I have tried to get acquainted with overall plant functioning and main concepts involved therein. The scope of Mechanical engineering is increasing day by day. It is a vital trade.

During training I was permitted to take training at many section of mechanical ( Boiler and maintenance, turbine , fan, Air pre heater, coal handling plant, water treatment plant, DM plant, coal mills) and general plant familiarization. I have summarized all the things, which I saw & learned at S.T.P.S. in this training report.

Thermal power stationA 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 either drives an electrical generator or does some other work, like ship propulsion. 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 fuel sources. Some prefer to use the term energy center because such facilities convert forms of heat energy into electrical energy.

AN INTRODUCTIONTOSURATGARH SUPER THERMAL POWER STATION

Suratgarh Super Thermal Power Station is owned by Rajasthan Rajya Vidhyut Utpadan Nigam Ltd. and is situated near village Raiyanwali about 25 KM from Suratgarh town, an ideal location for setting up a thermal power station in the state having regards to the availability of land, water, transmission network proximity to broad gauge railway and being an important load centre for north west Rajasthan. The techno-economic clearance for the prefect was issued by CEA in June 1991 – the planning commission accorded investment sanction for the project in Nov. 91 for a total estimated cost of Rs. 1253.31 crores on prices prevailing in Sept. 1990. The updated cost of the project is estimate at Rs. 2300 crores of including IDC.

It has generation capacity of 1500 MW and installed with six Units of 250 MW each. It is a coal base thermal station. Water and coal required in a large amount. Coal is received here from coal-fields of MP areas through railways and water is received from INDIRA GANDHI CANAL. The supply of coal is from MP, Jarkhand by rail. About 18000 tonne coal required per day for whole unit and each unit consumes 150 tonnes coal per day.

About 2x3 km2 area covered by plant and approximately 1800 employees works in a plant including chief engineer to labour. The supply electricity to the northern Rajasthan, Ratangarh, Bikaner, Ganganagar.

FUTURE EXPENSION

It has been decided to set up 2 X 660 MW super critical units (Unit # 7 & 8) at SSTPS. For this purpose about 446 Hectare land has been identified adjacent to the existing 6 X 250 MW plant. This land is under process of acquisition. M/s TEC have been appointed consulting engineers for this project. The state Govt. has also accorded its inpriciple approval for setting up in future, two additional units of 2 X 660 MW (Unit # 9 & 10) also based on super critical technology.

Installed capacityFollowing is the unit wise capacity of the plant.[2].

Stage Unit Number

Installed Capacity (MW)

Date of Comisioning Status

Stage I 1 250 May, 1998 RunningStage I 2 250 March, 2000 RunningStage II 3 250 October, 2001 RunningStage II 4 250 March, 2002 RunningStage III 5 250 June, 2003 RunningStage IV

ACKNOWLEDGEMENT

I wish to express my deep sense of gratitude to my training & placement officer Mr. Arjit Choudhary and H.O.D. of Mechanical Mr. D. N. Naresh for suggest and valuable guidance me for S.T.P.S. It is my proud privilege to express my sense of gratitude to Mr. Anil Dhawan (AEN) for providing me adequate facilities to undergo training at S.T.P.S.

I have in particular to appreciate the effort and keen interest taken by Mr. D. K. Nadheria (XEN), Mr. N. C. Jain (AEN), Mr. N. K. Jain (XEN) and Mr. Deepak Tater (JEN) for their kind help and assistance in under standing the working of diff. Equipment and for their kind guidance during the period of training. I am also grateful to Mr. Jangid (TA C&I) for their persistent help and for providing some of the technical data in form of computer print outs. Last but not the least I am equally obliged to all those engineers technical personnel and operators at S.T.P.S. who gave me their valuable time and rendered practical knowledge in my training period.And at last I want to thank my colleagues. Without their help guidance and suggestions it was not possible to produce this training report.

(Arvind sharma) 07EMTME021 7th sem.- B.Tech.,Mech.

M.A.I.E.T. JAIPUR.

THERMAL POWER GENERATIONSteam and water undergo various phases of “Carnot Cycle” in the Boiler, Turbine and other equipments during this process.In Thermal Power Station, fossil coal is used as fuel for steam generation in the Boiler. Steam so generated is utilised in Steam Turbine to generate mechanical energy for rotating the Generator for producing electric power.TUBINE Introduction The steam turbines and their auxiliaries installed have been manufactured by M/s BHEL . The turbines are three cylinders, compound 3000 rpm, double flow exhaust type reheat units with initial parameters of 13 kg/cm2 and 5 low pressure heaters are fed .The high pressure cylinder comprises of two curt is wheels as a regulation stage . Intermediate pressure cylinders comprise of twelve stages and each of the double flow section of the L.P. cylinder consists of four stages.Operation

There are two live steam lines connecting the boiler to the turbine. The superheated steam enters the H.P.turbine and strikes its blades hence heat energy of steam is converted into mechanical energy. The steam from H.P. turbine is reheated in reheaters and reheated steam is sent to I.P. turbine through hot steam lines. Here second stage of energy conversion is takes place. Then steam is sent to L.P. turbine from where it is ejected by vacuum ejectors and condensed. Here are two cold reheat and two hot reheat lines connecting the reheater and turbine. In each of the two live steam lines one electrically operated isolating valve, one water separator and one quick closing stop valve are mounted. The direction of revolution of turbine is clock wise when looking at turbine from front bearing pedestal. For the oil lubrication of bearings and for governing, the main oil pump driven shaft is assembled into the front bearing pedestal of turbine itself.

STEAM TURBINE

Introduction:

Steam turbine is a rotating machine which CONVERTS HEAT ENERGY OF STEAM TO MECHANICAL ENERGY.

In India, steam turbines of different capacities, varying from 15 MW to 500 MW, are employed in the field of thermal power generation. The design,

materials, auxiliary systems etc. vary widely from each other depending on the capacity and manufacturer of the sets.

Basic principles:The Thermal Power Plants with steam turbine uses Rankine cycle. Rankine cycle is a vapour power cycle having two basic characteristics:

1. the working fluid is a condensable vapour which is in liquid phase during part of the cycle and

2. The cycle consists of a succession of steady flow processes, with each processes carried out in a separate component specially designed for the purpose. Each constitute an open system, and all the components are connected in series so that as the fluid circulates through the power plant each fluid element passes through a cycle of mechanical and thermodynamic stages.

The turbine is of tandem compound design with separate HP, IP and LP cylinder. The HP & IP turbines are of single flow type while LP turbine is of double flow type; the turbine is condensing type with single reheat. It is basically engineered on reaction principle with throttle governing. The stages are arranged in HP, IP and LP turbines, driving alternating current full capacity Turbo generators.

GENERAL DESCRIPTION

Superheated steam (130 kg/cm2, 5350C) from the boiler enters into the High pressure turbine through emergency stop valves and four control valves. The high pressure turbine (HPT) comprises of 12 stages, the first stage being governing stage. The steam flow in High pressure turbine (HPT) being in reverse direction, the blades in high pressure turbine HPT are designed fro anticlockwise rotation, when viewed in the direction of steam flow. After passing through High pressure turbine (HPT) steam (27 kg/cm2, 3270C) flows to boiler for reheat and reheated steam (24.5 kg/cm , 535 C) comes to the intermediate pressure turbine (IPT) through two interceptor valves and four control valves mounted on the IPT itself.

The intermediate pressure turbine has 11 stages. High pressure turbine (HPT) and intermediate pressure turbine (LPT) through two crossover pipes. In low pressure turbine, steam flows in the opposite paths have four stages in each path. After leaving the low pressure turbine the exhaust steam (0.09 kg/cm abs) condenses in the condensers welded directly to the exhaust part of the low pressure turbine. Rotors of intermediate and low pressure turbines are connected by a semi flexible coupling.

The direction of rotation of the rotors is clock wise when viewed from the front bearing end towards the generators. The three rotors are supported in five bearings. The common bearing of High pressure and Intermediate pressure rotors is a combined journal and radial thrust bearing. Turbine is equipped with a turbine gear which rotates the rotor of the turbine at a speed of nearly 3.4 rpm for providing uniform heating during starting and uniform cooling during shut down. Condensate from the hot well of condenser is pumped by the condensate pumps, and supplied to he deaerator though ejectors, gland steam cooler and four number low pressure heaters. Steam is

extraction form the various points of the turbine to the heat the condensate in these heat exchangers. Form deaerator the feed water is supplied to boiler by boiler feed pumps though three number High pressure heaters.

Specification

Type - tandem compound condensing

Reaction

Rated output of turbine - 250 KW

Rated speed - 3000 RPM

Main steam temperature - 537 C

Rated pressure - 150 kg/cm

TURBINE COMPONENTSCasing or Cylinders: A casing is essentially a pressure vessel which must be capable of withstanding the maximum working pressure and temperature that can be produced within it. The working pressure aspects demand thicker and thicker casing and the temperature aspects demand thinner and thinner casings.

1. H.P Turbine Casing: The principal parts of the HP turbine casing are and axially split inner shell, enclosing the rotor and outer shell of a barrel-type construction. The barrel type of cylinder construction ensures symmetry of the wall thickness around the axis of rotation and hence the wall thickness itself is relatively less than that used in other type of construction.

2. I.P. Turbine Casing: The IP turbine is split axially and is of single shell design. The outer casing accommodates a double flow inner casing. The steam coming from the reheater is passed into the inner casing via admission branches which are symmetrically arranged in the top and bottom halves of the outer casing.

3. L.P Turbine Casing: The LP turbine is of double flow type. The casing is of triple shell, fabricated construction. The outer casing consists of the front and rear end walls, two longitudinal girders and a top cover. The inner shell of the inner casing acts as the guide blade carriers for the initial stages of the turbine. The guide blade carriers of the LP stage groups are so designed that, together with the inner casing, they form annular ducts which are used for extractions.

Steam Valves: A turbine is equipped with one or more emergency stop valves, in order to cut off the steam supply during periods of shut down and to provide prompt interruption of the steam flow in emergency. In addition

governing valves are used to provide accurate control of steam flow entering the turbine.

Blading: In steam turbine, the blades transform the thermal energy into mechanical energy. It is obvious that balding has got direct impact on the efficiency and reliability of turbine. Appropriate blade profile, with high aerothermodynamics efficiency having sufficient mechanical strength to withstand the steam forces. A final accurate check is made when the blades have been fitted into the rotor.

HP and IP Balding; These blades have a 50% reaction component and both fixed and moving blades have the same profiles. Each rotor blade is milled from a single piece of material complete with inverted T-root and integral shroud. In medium and low temperature regions, the fixed blades are made of solid drawn materials.LP Balding; The least three stages of the LP turbine have twisted blades. The differences between the circumferential velocity at the rotor blade root and tip is quite considerable and is taken into account by twisting the blade along its length. The fixed blades of the last two stages are hollow.

Shaft Glands: Labyrinth type glands seal the shaft where it passé through the casing. In the case of HP and IP Turbine, these consist of a series of sealing strips alternatively into the shaft and into stationary rings. In case of the LP turbine glands sealing strips are fitted into stationary rings only. The pressure of the steam leaking through the gland is reduced by converting the pressure energy into velocity energy, which is then dissipated as eddies as the steam passes through large no. of strips.

Bearings; Three journal bearings and one combined journal and thrust bearing are used for supporting the turbine shafting system. The HP Rotor is carried into two bearings, a simple journal bearing at the front end of the shaft and a combined journal and thrust bearing at the end immediately adjacent to the coupling with the IP Rotor. Intermediate pressure and low pressure rotors have a single journal bearing each at the rear ends.

Turning gear: The turbine is equipped with hydraulic turning gear capable to rotate the shaft system at high speed during shut-down and start-up periods in order to minimize.

The turning gear assembly is fixed on the front pedestal of HP turbine and engages the shaft of the main oil pump and thereby also turbine shaft via

the solined shaft, shaft flance and over-running clutch. The turbine generator shaft system is rotated by Hydraulic motor, wheel which is driven by pressure oil supplied by Jacking oil pump.

Thermal insulation of Turbine: The thermal insulation of turbine shall consist of Asbestos free Mineral Wool mixed with suitable filling and binding agent. Insulation thickness to be applied shall vary depending on the surface temperature prevailing in that zone. This is being done to achieve uniform rate of cooling of different section of turbine casing.

Turbine governing system

The main purpose of governor is to maintain this desired speed of turbine during fluctuations of load on the generator by varying steam input to the turbine.The governing system in addition to ensuring the falling load-speed characteristics of the turbine also ensures the following functions:1. The run up the turbine from rest to rated speed and synchronizing with the

grid.2. Meeting the system load variations in a predetermined manner, when

running in parallel with other machines.3. Protecting the machine by reducing the load or shutting off completely in

abnormal and emergency situations.

The governing system also includes other devices to protect the turbine from abnormal condition that may arise during operation.

In STPS By-pass Governing is used.

By-pass Governing: In this system, in general, the steam is supplied through a primary valve and is adequate to meet a major fraction of the maximum load which is called economic load loads less than this, the regulation is done by throttling steam through this valve. When the load on the turbine exceeds this economic load which can be developed by the unthrttole full flow through the primary valve, a secondary valve, is opened and throttled steam is supplied downstream, bypassing the first stage and some high-pressure stages. This steam joins the partially spent steam admitted through the primary valve, developing additional blade torque to meet the increased load.

Governing of Reheat Turbine In reheat turbines in cases of partial of full load ow off even after the HP control valves are fully closed the entrained steam in the reheaters and hot reheat line is more than enough to speed up the turbine above over speed limits. Hence it is necessary to provide stop valves and interceptor valves on hot reheat line before IP turbine. While the stop valve

is operated controlled similar to HP control valve but at a higher speed range by a secondary of pre-emergency governor as it is called. The valve remains full open at rated speed and starts closing at about 3% overspeed and is fully closed at about 5% over speed.

TURBINE OIL SYSTEM

Purpose of Oil SystemThe turbine of system fulfils four functions. It:

1. Provides a supply of oil to the journal bearings to give an oil wedge at he shaft rotates.

2. Maintaining the temperature of the turbine bearings constant at the required level. The oil does this by removing the heat, which is produced by, the shaft conduction, the surface friction and the turbulence set up in the oil.

3. Provides a medium for hydraulically operating the governor gear and controlling the steam admission valves.

4. Provides for hydrogen-cooled generators a sealing medium o prevent hydrogen leaking out aling the shaft.

BOILER

Introduction The boiler is the main part of any thermal power plant. It converts the fuel energy into steam energy. The fuel may be furnace oil, diesel oil, natural gas or coal. The boilers may be fired from the multiple fuels.The boiler installed in S.T.P.S. are made by M/s BHEL . Each of the boilers are single drum, tangential fired water tube naturally circulated over hanged, balanced draft, dry bottom reheat type and is designed for pulverizing coal firing with a max. Continuous steam output of 375 tons/hour at 138 kg/cm2 pressure and 540 degree cent. Temp. The thermal efficiency of each boiler at MCR is 86.8 %. Four no. Of bowl mills have been installed for each boiler. Oil burners are provided for initial start up and stabilization of low load .Two E.S.P. (one for each boiler) is arranged to handle flue gases from the respective boilers. The gases from E.S.P.are discharged through 180 meters high chimney. I.D. fan and a motor is provided near the chimney to induce the flue gases. The boiler is provided with a balanced draft consisting of two forced draft fans and two induced draft fans. Flue gases are utilized to heat the secondary air for combustion in the tubular type air heaters installed in the boilers. Since the boiler furnace is maintained at a

negative pressure, to avoid atmospheric air entering the furnace a hydraulic pressure is maintained at the furnace bottom. The water filled in the stainless steel seal through the hydraulic seal between the furnace ash hoppers and the water wall ring heater. Adequate clearance is also provided for the downward expansion of the furnace. Ash is formed by the result of burning of coal inside furnace. A small quantity of ash is collected in the bottom ash hopper and considerable amount of ash is collected in the E.S.P. and magnetic separator hopper. This collected ash is extract and disposed off in a slurry form in the ash disposal arc.

Basic theory and auxiliaries

The boiler also termed, as ‘steam generator’ is a container in which water can be fed and by the application of heat evaporated continuously into steam. The heat source is obtained by burning the fuel, which is coal here in our case .The walls contained in the boiler drum flows through the down corner water walls and then through risers back to the drum. This closed ckt. Movement of boiler water is termed as circulation. The heat energy applied in the furnace is absorbed by the water walls and water in this ckt. gets heated up .This give rise to the formation of steam bubble in the water walls and risers . The mixture of water and steam will rises continuously and move to the steam drum due to its lightness. The mixture of water and steam is continuously displaced by the colder water. In the drum there by establishing a natural circulation. As the mixture of water and steam takes place in the steam separators and the saturated steam is led into the upper heaters for further heating and water particles fall back into the drum water. After the feed control station the feed water enters into the economizer inlet header where the feed water is preheated before entering the boiler drum. The economizer is located below the real horizontal super heater in the boiler near gas pass. The economizer has a no. Of sections composed of parallel tube ckt. The flow direction of feed water in the economizer is in counter flow direction to the gas flow. The feed water coming out of the economizer of the outlet header enters the boiler drum. The boiler drum is located at 44-m level. There are four downcomers pipes connecting the water side of the drum to the furnace lower water wall inlet headers. The front and rear wall inlet header feed the front and rear furnace wall tubes. The furnace sidewalls are fed by the two side walls inlet header. The heat absorption takes place in the water walls. As a result of heat absorption there will be a mixture of water and steam in the ckt. Which is collected in the outlet headers .A series of riser tubes are provided to carry the water and steam mixture from the water wall header into the drum where separation of water and steam takes place .The wet steam which enter the drum from the riser tubes is collected in a compartment, formed by internal baffles. From here, the steam is

passed through too rows of turbo separator which has a primary and a secondary stage. In the turbo separator water is thrown off and the steam passes through the screen separators in the internal stage of separation.

CIRCULATION SYSTEM:

It is essential to provide an adequate flow of water and/or of water-steam mixture for an efficient transfer of heat from furnace to the working fluid and to prevent ‘burn-outs’. This is irrespective of the mode of circulation being used.

In STPS NATURAL type of circulation system are used.

Natural Circulation: In this type, no external pumping device is used for the movement of

the fluid. The difference in densities in contents of fluids in down comers from the drum and risers in the furnaces is used to effect the movement of fluids. This type of circulation is employed in most of the utility boiler.

The movement of the steam and water will increase with increased heat input to a maximum value or so called end point, after which further increase in heat absorption will result in a decrease in flow.One of the characteristics of natural circulation is its tendency to provide the highest flow in the tubes with the greatest heat absorption.

Heat Transfer in Boiler:

In boiler heat energy is released from the combustion of fossil fuels and the heat is transferred to different fluids in the system and a part of it is lost or left out as unutilized.

There are three modes of heat transfer :

Conduction Convection Radiation

Heat energy is transferred from a heat source to a heat receiver by one or more of these modes for which heat source should be at a higher temperature than the receiver.

In superheater tube with high temperature region but does not directly view the flame. Here the heat is transferred from flue gas to superheater tube metal by convection and by non-luminous radiation and in the tube metal by conduction and to the steam by forced convection.

The power plant boilers are large capacity steam generators used purely for the electrical power generation.

BOILER PRESSURE PARTS WATER & SATURATED STEAM CIRCUITS

Feed water is supplied to the steam drum from the economizer outlet

links. The waterside of the steam drum is connected with the furnace bottom water-wall header through down-comers.

The front and rear wall bottom headers feed the front and rear furnace wall tubes. The furnace sidewalls are supplied by the two side wall bottom headers. All the bottom headers are connected together in the form of a ring. Some tubes of the furnace rear wall form the supply tubes to the extended side wall inlet headers.

The extended side wall tubes terminate in the rear section of the side wall top headers.

The water in the furnace walls front and rear water-walls and the extended sidewalls absorb heat. The resulting mixture of water and steam is collected in the outlet headers and discharged into the steam drum through a series of riser tubes In the steam drum separation of water and steam takes place .The boiler water mixes with the incoming water .The saturated steam is led to the super heater connecting tubes.

Passing through the various stages of super heaters, the steam is superheated to the design temperature. From the super heater outlet header the superheated steam is led to the turbine via the main steam lines.

Steam Drum Internals:

The function of the steam drum internals is to separate water and steam from the mixture generated in the furnace walls. The steam purification primarily depends on the extent of moisture removal, since solids in steam are carried by the moisture associated with it. The drum internals reduce the dissolved solids content of the steam to below the acceptable limit.

The fitting and alignment of drum internals are very important fro its efficient performance. Any misalignment with gap will lead to heavy carry-over of impurities into steam which will get deposited in the superheater and turbines.

The separating chamber should be leak proof for efficient performance of drum internals. After the fit-up of drum internals is over, the inside of the drum should be thoroughly cleaned and should be free from foreign materials.

Economizer:

The purpose of the economizer is to preheat the boiler feed water before it is introduced into the steam drum, and to recover some of the heat from the flue gases leaving the boiler.

The economizer is located in the boiler real gas pass below the rear horizontal superheater. Each section is composed of a number of parallel tube circuits. All tube circuits originate from the inlet header and discharge into the outlet header through economizer intermediate headers and economizer hanger tubes.

Always use only deaerated water for boiler feeding. This is essential to keep down the inside corrosion of pressure parts including economizer.

In STPS Plain tube type of economizer are installed. The staggered formation induces more gas side turbulence than the in line and so results in a higher rate of heat transfer. However, it has the disadvantage of giving a higher draught loss.

Super heater:

Superheated (SH) are meant for raising the steam temperature above the saturation temperature present trend is to limit the superheated and reheated steam temperature around 5400C. The percentage of heat to super heater and reheater for the 165 bar boiler is approx 50%.

The super heater is composed of four basic stages or sections: a Pendant Spaced Section, a Platen Section, a Rear Horizontal Section and the Steam Cooled Wall and Roof Section.

The platen Section is located directly above the furnace in front the furnace arch. It absorbs heat mainly by radiation.

The Pendant Section is located behi9ng the screen tubes. The predominant mode of heat transfer is convection.

The Horizontal Section of the superheater is located in the rear vertical gas pass above the economizer. This is the primary superheater of the convective, counter flow type.The steam cooled wall suction from the side, front and rear walls and roof of the vertical gas pass.

Steam Flow: Saturated dry steam from the drum follows the course that is:

Steam cooled wall roof tubes –steam cooled side wall tubes – extended steam cooled side wall tubes – front steam cooled wall tubes – steam cooled roof and rear wall tubes- super heater rear horizontal assemblies – super heater de-super heater- platen super heater – pendant super heater.Super heated steam from the pendant super heater outlet header goes to the turbine via the main steam lines.After passing through the high-pressure stages of the turbine, steam is returned to the re-heater via the cold reheat lines. The reheat de-super heaters are located in the cold reheat lines.

Reheat flow through the unit is as follows: Front pendant re heater – rear pendant re-heater. After being reheated to the design temperature, the reheated steam is returned to the low-pressure section of the turbine via the hot reheat line.

Reheater: Reheater are provided to raise the temperature of the steam from

which part of energy already been extracted by HP turbine.The reheater is composed of two stages or section, the front pendant

vertical spaced platen section and the rea5r pendant vertical spaced platen section.

The rear pendant vertical spaced section is located above the furnace arch between the water- cooled screen tubes and rear water wall hanger tubes.

The front pendant vertical spaced plated section is located between the rear waterwall hanger tubes and the superheated platen section.

All reheater drains and vents are opened before lighting off. The vents and drains to the atmosphere must be closed prior to raising a vacuum in the condenser. Drains connecting with the condenser may be lift open until the boiler is under light load

Desuperheater: Desuperheaters are provided in the superheater connecting links and

the cold reheater lines to permit reduction of steam temperature when necessary and t maintain the temperatures at design values within the limits of the nozzle capacity.

Temperature reduction is accomplished by injecting spray water into the path of the steam through a nozzle at the entering end of the desuprheaterthe spray water source is from the boiler feed water system.

The location of the desuperheaters helps to ensure against water carryover to the turbine and also eliminates the necessity for high temperature resisting materials in the desuperheater construction.

Water Cooled Furnaces:

Bharat Heavy Electrical Limited has developed the modern water-cooled furnace. Furnace is the primary part of boiler where the chemical energy available in the fuel is converted to thermal energy by combustion. Furnace is designed for efficient and complete combustion. Major factors that assist for efficient combustion are time of residence (fuel) inside the furnace, temperature inside the furnace and turbulence which causes rapid mixing between fuel and air.It has following Advantage:

In furnace not only combustion but also heat transfer is taking place simultaneously.

The maintenance work involved in repairing the fire bricks is practically eliminated.

Due to heat transfer in the furnace the flue gas leaving the furnaces is reduced to the acceptable level to the superheating surfaces.

Operation: 1. Internal Deposits : It is essential that the tubes be kept free

form scale formation and copper and iron oxides deposits.

This is accomplished by proper boiler water and feed water treatment.In high pressure boilers iron and copper oxides introduced form the pre-boiler system, may lead to internal corrosion in the areas of deposits and eventually cause tube failures. Feed water treatment in this case comprises corrosion control in pre-boiler system.

2. Blow down : Boiler blow down used as a means of controlling boiler water concentration and to remove sludge formation. The frequency of blowing down depends upon local condition, such as: character of the water nature of feed water treatment, design and rating of e boiler etc. in most cases the continuous blow down system is sufficient.

3. Ash Deposits (slugging) : The amount and the rate of slagging depends largely on the type of fuel burned. The furnace walls cannot be entirely kept free from deposits, but should be kept “reasonably clean”. Heavy local accumulation could be avoided by proper use off soot blowing equipment. The wall blowers should not be used indiscriminately but only as required in the affected areas.

Gradual fouling of the furnace walls during commercial operation will cause increasing furnace outgas temperature and high steam temperature which may result in exceeding the range of steam temperature controls. Wall blowers can be used to keep these controls, within their operating range.

Flame inside the furnace should be watched and taken care to keep them off from impinging furnace walls. The selection of burners and loading is to be done such that the heat loading is uniform in furnace. The leakage if air through the furnace should be avoided.

Soot Blowers: Because of the mature of the deposits resulting from the combustion of coal, and to a relatively smaller extent from oil, means have to be provided to prevent an accumulation of deposits from chocking the boiler gas passes and to maintain the boiler heating surfaces in a suitably clean condition for effective heat transfer whilst on load. The most commonly used method of on load cleaning is soot blowing, although other methods, such as shot cleaning on economizers and tubular air heaters have been used to a more limited extent on order boiler.

Steam has mainly been used as the soot blowing medium, but recently the used low-pressure air as a soot blowing medium has been introduced as this offers a number of advantage.

BOTTOM CONSTRUCTIION

The construction of the furnace bottom depends on fuel and ash conditions. Bottom designs most commonly used for coal fired units are of the open hopper type, often referred to as the dry bottom type. For gaseous and oil fuels, closed bottoms are generally utilized.

Open Hoop Type Construction:

In this type of bottom construction two furnace water walls, usually the front and rear walls slope down toward the centre of the furnace to form the inclined side of the bottom. Ash and /or slag from the furnace is discharged through the bottom opening into an ash hopper directly below it. Depending on the height of the furnace, six to fourteen inches clearance between the furnace and ash hopper is allowed for downward expansion of the furnace walls. Either a water seal arrangement or a mechanical seal (expansion joint) prevents leakage of air at this point.

AIR AND GAS PATH

General: The total air flow through the unit is handled by two numbers axial

reaction forced draft fans and two numbers axial reaction primary air fans. The flue gas produced in the furnace from combustion of fuel is evacuated by two numbers radial double suction Induced draft fans. The schematic of air and flue gas system is enclosed.

Air System:

1. Combustion Air (Secondary Air) : The forced draft fans supply the required secondary air for combustion.

This air is preheated by two no. RPAH. Control of secondary air flow is done by FD fan blade pitch control. The distribution of hot secondary air to the wind box compartments is controlled by “Secondary air dampers”.

2. Air for Drying and Transportation of pulverized coal (Primary Air) : The cold primary air fans supply the air required for drying the coal in the tube mills/mixing box and for transporting the pulverized fuel from both ends of the tube mill to the coal burners. The primary air is heated in the primary sectors of the Rotary RAPH.

The control for the primary air pressure is achieved through PA fan inlet dampers.

3. Scanner Cooling Air : Each boiler is provided with 20 no. VISIBLE LIGHT SCANNER. The two no. of scanner air fans are provided to supply the required air for cooling these flame scanners. The supply of air is taken from FD fan discharge. The air is filtered and boosted to the required pressure by the scanner air fans. Additionally an emergency air supply connection from atmosphere is provided for supplying the cooling air to the scanners in case both FD fans trip.

4. Seal Air : Six no. of seal air fans are (2 nos. per mill) are provided for each boiler. The sealing air is required for mill trunounim mill discharges valves and gravimetric feeders, of the two seal air fans provided for each tube mill, one is in operation and the other standby. The seal air takes suction from the atmosphere.

Gas system: The flue gases produced in the furnace as a result of combustion, travels upward in the furnace, across the horizontal pass and downward through the second pass of the boiler to the air preheater. Two no. of Induced draft fans are provided to evacuate the flue gas from furnace to the chimney. The ID fans are provided with hydraulic coupling and inlet damper control. PRESERVATION OF BOILERS

Atmospheric corrosion of ferrous materials proceeds rapidly in the presence of oxygen and moisture. The oxides produced are objectionable and can be transported to critical heat transfer areas as well as to the turbine. Pit type corrosion can also occur in walls. In large boilers, with numerous complex circuits and bends, it is practically impossible to completely dry the boiler in preparation for storage.

GUILLOTINE GATE

In the power plants, usage of guillotine gate is probably the best device for isolation and it can be relied upon to operate completely even in hot, noxious and dirty environments and under corrosive conditions.Guillotine gates are recommended for EP inlet and outlet, ID fan inlet and outlet, Primary air fan outlet and mill isolation from cold and hot air.Guillotine is simply a free moving obstruction tolerant blade which travels in a rigid frame, is triggered by reliable operator, travels to close against a non-fouling rigid seat, and has adequate provision for clean out.Fro services operating 2600C or above, bonnet enclosures are provided to limit thermal differential during operation.

The guillotine must be used only in a fully opened fully closed position and never left in an intermediate position. When the gate blade is open, the gate blade must be withdrawn completely form the seal. If the gate blade should stall while closing run the gate blade up to 150 mm and attempt to close again. This procedure until the gate blade is fully closed.

Fuel Oil Burning System

Fuel Oil Atomization: Atomizes the process of spraying the fuel oil into fine mist, for better mixing of the fuel with the combustion air. While passing through the spray nozzles of the oil gun, the pressure energy of the oil converts into velocity energy, which breaks up the oil stream into fine particles. for satisfactory atomization the viscosity shall be less than 15-20 centistokes.

HEA Ignitors: HEA Ignitors are provided in this Boiler. This ignitor uses LFO/HFO as main fuel and this is ignited using spark and is mounted adjacent to oil gun.

Air Cooled Oil Guns: The atomized assembly of an operating oil gun is protected from the hot furnace radiation by the flowing fuel oil and steam which keeps it relatively cool. The oil gun assemblies supplied for this project have been designed for air cooing provision.

Burner Trip Valves: To control the atomizing medium and fuel flow to the oil guns, pneumatic operated trip valves are used.

Main Parts of Boiler:1. The boilers consist of the following main parts:2. Forced Draft Fan (FDF)3. Air Preheater (RAH)4. Burners5. Furnace6. Up Rise Tubes7. Down Comer Tubes8. Water Tubes9. Super Heaters10.Gas Recirculation Fan (GRCF)11.Re-Heater12. Induced Draft Fan (IDF)

AIR PREHEATER

Air preheater is a heat exchanger in which air temp. is raised by transferring heat from other fluids such as flue gas . Since air heater can be successfully employed to reclaim heat from flue gas at lower temp. level ,then it is possible with economizer the heat ejected to chimney can be reduced to a great extent thus increasing the efficiency of a boiler.

Regeneration Air Pre Heater

It is an essential boiler auxiliary, because hot air is necessary for rapid and efficient combustion in the furnace and also for drying coal in the milling plant.

Specification

1. Heating element - Hot end, Hot intermediate, Cold end Materials - Carbon & Corten steel

2. Rotor main drive motor - 11 kW, 1450 rpm, 50 Hz Coupling - Fluid coupling 11.5 fcu2. Bearing

Guide bearing : Spherical roller bearing Support bearing : Spherical roller thrust Thermostat: Burling thermostat

3. Oil capacity Guide brg. Housing : 25 lt. Support Brg. Housing: 150 lt.

4. Steam Coil Airpreheater Number of steam Coil APH : 2 Nos per boiler Installed position : Vertical Design Pressure: 20 kg/cm2

Design Temperature: 2500C Weight of One steam coil APH: 1950 kg.

Description

HOW THE LJUNGSTROM REGENERATIVE AIR PREHEATER WORKS

The Ljunstrom RPAH absorbs waste heat from flue gas and transfers this heat to incoming cold air buy means of continuously rotation heat transfer elements.As the rotor slowly revolve the mass of the elements alternately through the air and gas passages, heat is absorbed by the element surfaces passing through the hot gas stream; then,, as same surfaces are carried through the air stream, they release the stored up heat thus increasing the temperature of the incoming combustion or process air.

Parts of RAPHHeating Element

The heating element is a compact arrangement of formed metal sheets contained in the rotor in two or more layers.Cleaning - A pressure pump, garden type, pneumatic spray gun of 5 to 10 lt. capacity is suitable to apply anti rust oil with good penetration.

Rotor Bearing

The complete rotor is supported by a thrust bearing. The load is transmitted to the thrust bearing by a trunnion, bolted to the lower end of the rotor post of by an extension to the rotor post. To guide the upper end of the rotor, a guide trunnion is bolted to the face of the rotor post. The position of this trunnion is maintained by a radial guide bearing assembly. Both the support and guide bearings are lubricated with an oil bath.

Rotor Drive Unit

The driving force for turning the rotor is applied at its periphery. A pin rack mounted on the rotor shell is engaged by a pinion attached to the low speed shaft of a power driven speed reducer. Auxiliary Drive - This drive ensure the continued operation of the Preheater even if power to the electric motors interrupted. Generally, Air Motor is used for the auxiliary drive.Caution - Air motor should not be operated without the Lubricator.

Rotor seals

Seals are providing at both the ends of the Air Preheater to minimize leakage between the air side and the gas side. The hot and cold end radial seals are attached to each diaphragm of the rotor. Seals provided at the rotor post are set to operate with minimum clearances with respect to the horizontal sealing surface go the sector plate. The bypass / circumferential seals provide sealing between the periphery of the rotor and the connection plate/housing, all seals may be adjusted to necessary clearances.

Cleaning Device

Cleaning Device is provided at the cold end (gas side) to remove soot deposits on the heating elements.

It consists of an electric motor coupled to a gear driven crank mechanism which oscillated the swivel heater carrying the nozzle pope or pipes.

Water washing of air heater

When residua deposit accumulations cannot be removed readily by soot blowing, it, sometimes becomes necessary to water wash the heating surface to maintain acceptable draft losses through the air preheater. Most deposit accumulations forming on the air prehearater heat transfer surface are highly soluble in water and, therefore, are easily removed by washing provided a sufficient quantity of water is used.Water source - Fresh water is ordinarily used for washing air preheaters. The most commonly used sources of water for washing air preheaters are rivers, lakes, and ponds although well water and house service water are also used extensively.

LubricationRotor Support Bearing

The rotor support bearing of the Ljungstrom air preheater may be lubricated by one of the two methods. It may be either bathe lubricated, or lubricated by means of a combined bath and forced circulation and filtering system. The choice of lubricant will depend on the expected maximum operation temperature of the support bearing. This, In turn will depend upon the type of lubrication an cooling system, and upon condition surrounding the support bearing.The lubrication oil used may be either an FP type of lubricate with lead napthenate additive, pr a straight mineral oil.The oil selected for the support bearing will also be suitable for the GUIDE BEARING

Rotor stoppage alarm

It is a device which is used to give a signal when the rotor is stopped without our control.

Reason for rotor stopping remedial measure

1. Big foreign materials jammed in Thoroughly cleaning the Air Preheater after

Between the rotor and sector plates. maintenance.

2. Main drive will fail Proper maintenance of the main motor

ADVANTAGE

1. It compact and hence save space and structure coal.2. This is the type can be economically used for high capacity boiler.3. Holes in the elements due to corrosion etc. will not materially affect for

performance of the heater.4. Ducting arrangements are neat, streamlined, simple and less costly5. Less weight of metal permit economic usage of alloy steel.

DISVANTAGE

1. Moving parts increase the possibility of outages.2. Leakage of air into, gas , dust into air, because of entrainment by rotary action, Leakage of air into gas because of the impossibility of perfect sealing.

Fouling , plugging and Corrosion

Deposits in airheateras are initiated by condensation of acid or moisture from flue gas on metal surface. Degree of fouling depends on air heater heating element metal surface. Minimum metal temperature occurs at the cold end, where as a result most fouling and corrosion occur.As coal contains less sulphur corrosion is not nor normally as much a problem as fouling and hence lower exit gas temperature to a level of 1200C. The gas outlet temperature and /or air inlet temperature has to be raised to restrict the corrosion to the permissible level. During starting and at low loads the flue gas exit temperature fails to a low value that will lead to corrosion.

CONDESER The functions of condenser are:1. To provide lowest economic heat rejection temperature from the steam.

Thus saving on steam required per unit of electricity.

2. To convert exhaust steams to water for reuse this saving on feed water requirement.

3. Deaeration of make-up water introduced in the condenser.4. To form a convenient point for introducing makes up water.

IN STPS RVUN SURFACE CONDESER is used.

Surface Condenser: This type is generally used for modern steam turbine installations. Condensation of exhaust steam takes place on the outer surface of the tubes, which are cooled by water flowing inside them.The condenser essentially consists of a shell, which encloses the steam space. Tubes carrying cooling water pass through the steam space. The tubes are supplied cooling water form inlet water box on one side and discharged, after taking away heat form the steam, to the outlet water box on the other side.Instead of one inlet and one outlet water boxes, the may be two or more pair of separate inlet-outlet water boxes, each supplying cooling water to a separate bundle of tubes. This enables cleaning and maintenance of part of the tubes while turbine can be kept running on a reduced load.

Description of condenser

The condenser group consists of two condensers, each connected with exhaust part of low pressure casing. A by-pass branch pipe has interconnected these woe condensers. The condenser has been designed to create vacuum at the exhaust of steam turbine and to provide pure condensate for reusing as feed water for the boilers. The tube layout of condenser has been arranged to ensure efficient heat transfer from steam to cooking water passing through the tubes, and at the same time the resistance to flow of steam has been reduced to the barest minimum.

350% capacity condensate pumping sets are installed for pumping the condensate from condenser to the deaerator4 through low-pressure heaters. Two pumps are for normal operation and one works as stand by pump.

Materials for Condenser tubes

Selection of tube material mainly on the quality of cooling water and the cost. Coppers alloys are preferred as copper has very high heat transfer coefficient. But as copper has very little mechanical strength; it has to be reinforced by alloying with other metals.

Stainless steel tubes has also been used and has good corrosion resistance though heat transfer coefficient is quite lower ht an the copper alloy.

Regenerative Feed Heating System

If steam is bled from a turbine and is made to give up its latent and any superheat it may possess, to a heater this system is called regenerative, because the fluid gives up heat, which would be otherwise wasted, to the fluid whilst in another state to raise its temperature. The highest theoretical temperature to which the feed water may be raised in the heater is the saturation temperature of the bled steam. There is an optimum point at which the steam is bled form the turbine once a feed temperature is selected, a tapping point near the stop valve produces no gain in efficiency as practically live steam is used for heating.

Regenerative system of 250 MW unit

The regenerative system of the turbine consists of four low-pressure heaters, two gland coolers, one deaerator and three high-pressure heaters. The condense is drawn by condensate pumps from the hot well of condenser and is pumped to the deaerator through gland coolers and low pressure heaters where it is progressively heated up by the steam extracted from seals and bled points of the turbine. The drain of condensate steam on LP heaters No. 2,3 and 4 flows in cascade and is ultimately pumped into the main condenasate line after heater No.2 or flows to condenser. The feed water after being deaerated in the deraerator is drawn buy the boiler feed pump and pumped to boiler through high pressure heaters where it is heated up by the bled steam from the turbine. The drain of condensed steam of HP heaters flows in cascade and under normal load conditions flows to the deaerator.

HP-LP BYPASS SYSTEM

This bypass system has been provided to allow the steam generator to build up, during start-up, matching steam parameter with the tribune. The steam generated is dumped into the condenser, thus avoiding loss of boiler water. This system enables starting of he unit of sliding parameters and also facilitates hot restarting of the unit. In the event of loss of load on the turbine, the bypass system disposes the steam produced by; the boiler automatically to he condenser without affecting the boiler operation.

The bypass system had two sections: HP & LP. The HP-Bypass system diverts the steam before main steam valve to he cold reheat CRH line. HP Bypass system also reduces the rated steam parameters of the incoming steam from the superheated to the steam condition expected in the CRH line (i.e. steam temp. and pressure after HP turbine exhaust).

The LP Bypass diverts the incoming steam from hot reheat line before intercepting valves to he condenser after reducing the HRH steam parameters to the conditions approximately to that of LP steam turbine exhaust steam.

HP Bypass station is utilised for the following tasks:

1. To establish flow at the outlet of superheated for raising boiler parameters during starts up.

2. To maintain or controls steam pressure at pre-set value in main steam line during start up.

3. To warm up the steam lines.4. To control steam temperature down of HP bypass at the reset value

LP Bypass station is utilised for the following tasks:

1. Control of steam pressure after reheater.2. Establish flow of steam from reheat lines to condenser by its opening,

proportional to the opening of HP bypass valves.

DEAERATER Condensate from hot well is pumped to de aerator by

condensate extraction pump. Functions of de aerator are: -1. Removal of dissolved air/oxygen in boiler water.2. Chemical dosing for maintaining quality of boiler water.

3. Regenerative heating of feed water for increasing its temperature and efficiency of plant.

4. Storage of feed water in water/steam cycle.

Booster Pump

WORKING:50 % tandem boiler feed pump sets are supplied to this contact, three pump sets for each boiler. Two sets are run in parallel, supplying each boiler, with one pump set being on stand-by. Each pump set consists of a “FA1856” booster pump, directly driven form one end of the shaft of an electric driving motor, and a “FK6D30’ boiler feed pump driven from the opposite end of the motor shaft through a variable speed turbo-coupling. The drive is transmitted, in each case through a spacer type flexible coupling.The bearings in the booster pump and pressure stage pump and in the motor are lubricated from a forced lubricating oil system incorporated in the turbo coupling.The booster pump is a single stage, horizontal, axial split casing type, having the suction and discharge branches on the casing bottom half, thus allowing the pump internals to be removed without disturbing the suction and discharge pipe work of the alignment between the pump and the motor.The pump shaft is sealed at the drive end and the non-drive end by mechanical seals which are flushed by a supply of clarified water.

TECHNICAL DATA: Pump type : FA1856 Direction of rotation : Anti - clockwise (Viewed from drive end) Liquid pumped : Boiler Feed Water Suction temp. : 161.10C Flow rate : 490 m3/hr. Efficiency : 81 % Input power : 151 KW Speed of pump : 1485 rpm

Components of Booster Pump:

Pump Casing Rotating Assembly

Journal and Thrust bearing Bearing Housing Mechanical Seals Motor / Pump Casing

Boiler Feed pump

WORKING:

The FK6D30 type Boiler Feed Pump is a six stage, horizontal centrifugal pump of barrel casing design.The pump internals are designed as cartridge which can be easily removed for maintenance without disturbing the suction and discharge piping work or the alignment of the pump and the turbo coupling.The pump shaft is sealed at the drive end and non-drive end by mechanical seals, each seal being flushed by water in a closed circuit and which is circulated by the action is cooled by, [assign through a seal cooler, one per pump, which is circulated with clarified cooling water. The rotating assembly is supported by plain white metal lined journal bearings and axially located by a Glacier double tilting pad thrust bearing.

TECHNICAL DATA:

Pump type : FK6D30 No. of stages : 6 Direction of rotation : Anti – clockwise (Viewed form drive end) Suction temp. : 161.10C Design flow : 490 m3/hr. Efficiency : 81 % Speed : 5310 rpm Input power : 3322 KWDrive Motor Manufacturer : B.H.E.L., Haridwar

Rating : 3550 KW Speed : 1492 rpm Electrical supply : 6.6 kv, 3-ph, 50 Hz

Components of Boiler Feed Pump: Pump Casing Discharge Cover Suction Guide Ring Section Assembly Mechanical Seal Journal and Thrust bearing Bearing Housing Hydraulic Balance Flexible Coupling

The lubricating oil for the journal and thrust bearings, of the booster pump and boiler feed pumps and the drive motor will be supplied form the lubrication oil system associated with the hydraulic coupling and should be as follows:

Condensate Extraction Pump

Technical Specification:

Type : EN 8 H 32

Direction of rotation viewed : Clock-wise

Suction temp. : 46.10C

Sp. Gravity : 0.9901

Speed : 1485

Power absorbed : 266 KW

Efficiency : 78 %

WORKING:

The condensate Extraction Pumps are of the vertical, eight stage, Centrifugal canister type, with the driving motor supported on a fabricated head piece and the eight inter connected pump stage are suspended below the head piece. The pump discharge branch and suction branch are formed on the head piece above floor level. The eight pump stages are contained within a fabricated canister, and each stage casing is located by spigot and secured together with bolts, nuts and lock washer. The canister is suspended and secure to a foundation ring with screws. The head piece is also secure to the canister with screws.

Each pump directly driven through a flexible coupling by a 325 KW electric motor. Components of Condensate Extraction Pumps:

Head piece Foundation Ring Canister Stuffing Box Assembly Thrust and journal bearing assembly Coupling Driving motor

Variable Speed Fluid Coupling

Some boiler feed pumps the KHI types are coupled with their driving motor through a variable speed hydraulic coupling. The hydraulic coupling serves the purpose of controlling the speed of feed pump for maintaining definite delivery head and delivered quantity of the feed water as per requirement of the boiler. This reduces the power consumption particularly at part load operation.

Basic Principle and Operation:

A fluid coupling is basically a combination of pump and turbine connected in series. The rotating impeller energy to the operating fluid. The resultant centrifugal force causes the fluid to flow outwards whereby the velocity is increased by the impeller. The flow of the fluid into the runner takes place at the outer diameter, where the energy is transmitted from the fluid. The fluid contained in the runner blade chambers then flows inwards to the centre and back into the impeller blade chambers.The working circuit is governed by a system which can continuously extract or supply the working compartment fluid. This enables precise adjustment of the driven machine speed to be achieved. The working compartment is the chamber between the primary and secondary wheels which is a connected to a rotating chamber consisting of an inner and an outer shell. The oil level in the working compartment determines the speed at the output side of the coupling and depends upon the radial position of a scoop tube located in the scoop chamber.

In SURATGARH THERMAL POWER PLANT, there are three fans:

1. F.D.FAN (Forced fan)2. I.D.FAN (Induced fan)3. P.A.FAN (Primary fan)

Forced Draft FanIn the Axial Reaction Fans (Type AP), the major part of (about 80 %) energy transferred is converted into static pressure in the impeller itself. The rest of the energy is converted into static pressure in the diffuser. These fans are generally driven at constant speed. The flow is controlled by varying the angle of incidence of impeller blades. It therefore becomes possible by this process to achieve high efficiencies even during part load operation. The blade pitching operation is performed by mechanical linkages connected to a hydraulic servomotor which is flanged to the impeller.

Technical Data:

Application : Forced Draft Fan

No. off : 2

Medium handled : Atmospheric Air

Orientation : Vertical Suction and

Horizontal Delivery

Capacity : 105.2 m3/Sec

Temp. Of medium : 450C

Speed : 1480 rpm

Coupling : Rigiflex coupling

Drive motor

Rating : 700 KW

Speed : 1480 rpm

Fan Weight : 8 Tones

Type of fan regulation : Blade Pitch Control

When looking in flow direction, the fan consists of the following Components:

Suction chamber

Fan Housing

Rotor Consisting go shaft, one impeller with adjustable blades with

pitch control mechanism.

Main bearings (Antifriction bearings)

Outlet Guide Vane housing with guide vanes

Diffuser

Fan Accessories: Rigiflex Shaft Coupling:

The fan shaft is connected to the motor shaft by means of Rigiflex couplings.

Oil Circulation System : The oil system consists of an oil tank, two pumps(on Stand by), filters, coolers and necessary fitting.

Drive Motor: These fans are driven by constant speed Synchronous Induction motors. Silencer: These fans are provided with a silencer to attenuate. Airborne noise to acceptable level.

Lubrication: The lubrication oil for the fan bearings ate supplied by the centralized oil pumps which supply oil for the hydraulic servo meter also.

Recommend Oil: Servo Prime - 68 of IOC

Turbinal - 68 of HPC

INDUCED DRAFT FAN

Radial fans manufactured are single stage, single/ double suction, simply supported/overhung centrifugal machine which can be used to handle fresh air as will as hot gases in power plant application. In this, the medium handled enters the impeller axially and after passing through the impeller leaves radially. A large part of the energy transferred to the medium is converted into kinetic energy as the medium passes through the impeller. The spiral casing converts part of the kinetic energy in the medium to pressure energy. These fans are generally driven by constant speed motors. The output of the fan is usually controlled by inlet dampers or inlet guide vanes or by varying the speed of the fan by suitable speed control device.

Technical data: Application : Induced Draft Fan

No. off : 3

Type : NDZV 33 S

Medium handled : Flue Gas

Orientation : 450 Top incl. Suction

Bottom Horizontal,

Delivery

Capacity : 250.5 m3/Sec

Temp. of medium : 1540C

Speed : 740 rpm

Coupling : Hydraulic Coupling

Drive motor

Rating : 1750 KW

Speed : 740 rpm

Fan Weight : 52.7 Tones

The major sub-assemblies of the fan are as follows:

Impeller with shaft assembly

Bearings and thermometers

Suction chamber and spiral casing

Flow regulation devices

Shaft seals

Couplings

The fan is drive by an electric motor. The fan bearings are lubricated by means of oil

lubrication. The oil must not foam during operation. Foam removing agents containing silicon must not be utilized. The oil must have good anti-corrosion properties.

PRIMARY AIR FAN

PA Fan is same as forced draft fan. Only the differences is that in this fan there are two stages AP fan(Axial Profiles fan), the two impellers are connected by means of a link rod, with this we can operate both the impeller blades synchronously.

Technical data : Application : Primary Air Fan

No. off : 3

Type : AP 2 17/12

Medium Handled : Atmospheric Air

Speed : 1480 rpm

Rating : 1400 KW

Fan wt. : 10.8 tones

E.S.P. E.S.P THEORY

E.S.P. is a highly efficient device for extraction of suspended particles and fly ash from the industrial flue gases.

WORKING PRINCIPLE :

E.S.P can handle large volume of gases from which solid particles are to be removed Advantages of E.S.P. are :- High collection efficiency Low resistance path for gas flow Treatment of

large volumes at high temp.Ability of cope with corrosive atm.An E.S.P. can be defined as a device which utilized electric forces to separate suspended particles from flue gases WORKING STEPS : Ionization of gases and charging of dust particles Migration of dust particles. Deposition of charge particles on collector surface. Removal of paE.S.P. consist of two sets of electrodes, one in the form of thin wire, called discharge or emitting electrode in the form of plates. The emitting electrodes are placed in the center or midway between two plates and are connected to-ve polarity of H.V. D.C source of order of 37 KV collecting electrodes are connected to + ve polarity. The voltage gradient between electrodes creates “CORONA DISCHARGE”, Ionizing the gas molecules. The dust particles present in flue gases acquire -ve charge and deposited on collecting electrodes. The deposited particles are removed by knocking the electrode by a process called “RAPPING’ DONE BY “ RAPPING MOTORS”.

Cooling Towers:Cooling towers are heat removal devices used to transfer process waste heat to theatmosphere. Cooling towers may either use the evaporation of water to remove process heat andcool the working fluid to near the wet-bulb air temperature or rely solely on air to cool theworking fluid to near the dry-bulb air temperature. Common applications include cooling thecirculating water used in oil refineries, chemical plants, power stations.Cooling Water Pump:The motor of the CWP has following specification;

Type: Y1600-16/2150

Out Put Power: 1600KW

Stator Voltage: 6.6KV

Speed: 372rpm

Frequency: 50Hz

Stator Rated Current:182A

Stator Connection: 2Y

Ambient Temperature: 50C

Insulation Class B

Weight 17500Kg

CW Pump:

Type is single stage double suction centrifugal pump

Type: 1400S25-1

Capacity: 16000m3/H

Speed: 370rpm

Power : 1600KW

Weight : 35000kg

Head : 25m

NP SHR : 8.5m

COAL HANDLING PLANT Wagon tippler has rated unloading capacity of twelve box wagon per hour, including shunting and spotting time of haulage equipment. For vibrating feeders of capacity 350 tons/hr. each have been provided feeding unloads coal. A steel hopper has been provided in crusher house to receive coal and distribute it through manually operated rack and pinion gate to three vibrating screens of 675 t/hr. capacity each coal above 200 mm size passes on granules for crushing and reduction in size. Coal below 20 mm size passes granular and discharged on to crushed coal conveyor belt. Following permutation and combination of operation are possible with installed system. To transfer all crushed coal received from crusher house to live storage pipe. To transfer part of received crushed coal to plant and to balance to storage yard. To deliver the raw coal bunkers part and received crushed coal mixed with balanced coal from the live storage pipe. To transfer the plant crushed coal at 750 T/hr from the reclaim live pile and simultaneously stock and s/ road. the vibrating ones as stated above can be obtained by the use of flap gates which are installed on various chute and two vibrating feeders, installed on tower. The coal carried on various conveyers shall be main monitored to ensure proper loading and distributing weightless and vibrating feeders.

ASH HANDLING PLANT The ash handling system provide for continuous collection of bottom ash from the furnace hearth and its intermittent removal by hydro ejectors to a common slurry sump. It also provides for removal of fly ash to the common slurry sump. Each boiler is provided with ash precipitator for collecting the fly ash from the flue gases with high efficiency of collection to minimize the dust mains and to reduce the wear of induced draft fan. The fly ash separated from flue gases in the ash precipitator is collected in hoppers at the bottom from where it is mixed with water to form slurry and disposed off to pumping area by means of hydro ash pumps. Bottom ash from the boiler furnace is passed through slag crushers and then slurred to the slurry chamber at the suction of the ash disposal pumps. These are high pressure and low pressure pumps for this purpose. At a time one pump is working and other two are stand by. From the ash disposal pump house ash slurry is pumped through pipe lines to the ash dump area within about 1.5 km away

from the ash disposal pump house. Too separate discharge lines are provided one for each unit but only one line is used. The ash slurry from the two units is taken in one discharge line through electrically operated valves.

WATER TREATMENT

INTRODUCTION: The natural water contains solid, liquid and gaseous impurities and therefore, this water cannot be used for the generation of steam in the boilers. The impurities present in the water should be removed before its use in steam generation. The necessity for reducing the corrosive nature & quantity of dissolved and suspended solids in feed water has become increasingly important with the advent for high pressure, critical & supercritical boilers.

IMPURITIES IN WATER:

The impurities present in the feed water are classified as given below –

1. Undissolved and suspended solid materials Turbidity and Sediment Sodium and Potassium Salts Chlorides Iron Manganese & Silica

2. Dissolved Salts and Minerals Calcium and Magnesium Slats

3. Dissolved Gases Oxygen Carbon Dioxide

4. Other Materials Free Mineral Acid Oil

RAW WATER AND IMPURITIES:

Source: The various sources of water can be broadly classifies as:

a) Rain waterb) Surface water (Rivers, Streams, Ponds, Lakes)c) Ground water ( Springs, Shallow wells and Deep Wells)

Impurities:

The major impurities of water can be classified in three main groups are: Non- ionic and Undissolved :

These are mainly turbidity, slat,mud, dirt and other suspended matter

1. .Ionic and Dissolved 2. Gaseous Impurities : Carbon Dioxide and Oxygen

Removal Of Impurities: Our major concern is industrial water treatment, whereby, water used directly or indirectly in an industrial process is made suitable for that particular application. The use of water in boilers fro steam generation is an obvious industrial use. Depending on the process, varying degrees of purity of treated water are required. For example, a textile processing unit will require soft and clear water for process use: a chemical plant or electronic components manufacturing unit will require ultra-pure water containing total dissolved impurities not exceeding 0.5mg/litre or less.

MILLING PLANT

Pulverized coal Systems:

For steam generation, there is basically system of pulverization normally in STPS plant used is Direct Firing System

Direct Firing System:

1. Hot Primary System:

In this system the fan is located before the pulverized and handles complete primary air required for drying a transporting the coal. Disadvantages are that the fan is required to handle high temperature air resulting in high a fan power. Separate sealing air fans are required to seal the mill and Journal bearings.

2. Cold Primary Air System:

The primary air fan handles clean cold air either from FD fan discharge or taking suction from atmosphere. The advantages are saving in fan power and maintenance. The only disadvantage. Is the cost increase due to additional duct work and air heater.

3. Suction System:

In this system the mill operates under negative pressure. Suction being created by an exhauster placed after the mill. The exhauster handles all the coal air mixture and forces it into the burners. The advantage of suction system is that the plant can be maintained clean. The disadvantage of this system id that he high speed exhauster has to handle coal air mixture and tends to wear more as the pulverized size increase.

4. Pressurized Exhauster system:

In this system the mills operate under positive pressure. With exhauster provided at hr exit of pulverize to boost the pulverized coal into the pressurized furnace. Since the pulverized operates with lesser pressure than forced draft fan pressure.

In plant TUBE type of pulverized mill is used.

Drum/Tube mills:

This type mills is slow speed type. They operate at a speed of 17-20 rev/min and formerly were designed as suction mills. The mill drum carrying the ball charge rotate in the antifriction bearings. Raw-coal is fed to the drum through the inlet elbow and gets crushed to powder inside the mill drum. The ball charge and the coal are carried to certain height inside the drum and slowed to fall down. Due to the impact of the balls on cola particle sand due to attrition as the particles slide over each other and also over the liners, the coal gets crushed. Hot flue gases are used for drying and transporting the pulverized coal from the mill to the classifier. As a result of this high availability in a tube- ball mill installation, it is not normal to provide standby milling capacity; this helps to reduce the overall capital cost of the plant. Power requirements have also been reduced, but they are still much greater than those for medium-speed mills.

Advantage:

High output possible, up to 50 tones per hour.

No maintenance over long periods

High availability

Because of high availability no stand by capacity is required

No mill rejects, no problems with ‘tramp’ iron

Reserve of fuel within mill makes output more stable.

Disadvantage:

High power consumption

Some problems with control of coal level within the mill.

Virtually constant power consumption at all loads; low load operation of

therefore not economical.

With high moisture content fuels a high primary air temperature is

required because of the low air /fuel ratio

Unplanned stops leave the mill full of coal which, under unfavorable

conditions, can ignite. This coal has to be quenched and even dug out

otherwise the mill cannot be restarted.

COAL FEEDERS

Coal feeders deliver the cola from the bunkers to the mill. Since the amount of coal delivered determines the output of the mill, if follows that the cola flow, through the feeder has to be controlled. This is normally achieved either by control of feeder speed or by control of the position of a scraper knife or plough.

In plant Drag Link Coal Feeders type of Coal Feeder is used.

Drag Link Coal Feeders:

In this type of cola feeder, the coal leaves the bottom of the bunker through a large outlet hopper which is connected directly to the feeder casing. The cola falls on the feeder top plate and is dragged along by the conveyor chain to the point where the top plate ends. The depth of the cola bed is controlled by the height regulating gate. At the end of the top plate the cola falls down between the stands of the chains to the Point of discharge at the mill inlet coal delivery chute. The rate of coal feeds controlled by variable speed motor drive.

. DUST EXTRACTION PLANT

In plant the methods used for the removal of dust from gases are ELECTROSTATIC PRECIPITATOR which uses electrical forces to remove the dust from the gas stream.

Electrostatic Precipitators

Working Principle:

The principles upon which an electrostatic precipitator operates are that the dust laden gases pass into a chamber where the individual particles of dust are given an electric charge by absorption of free ions from a high voltage d.c. ionizing field. Electric forces cause a steam of ions to pass from the discharge electrodes to the collecting electrodes and the particles of dust entrained in the gas are deflected out o the gas steam into the collecting surfaces where they are retained, either by electrical or molecular attraction. They are removed by an intermittent blow usually referred to as rapping, this causes the dust particles to drop into dust hoppers situated below the collecting electrodes.

There are four different steps in the process of precipitation

1. Ionization of gases and charging of dust particles.2. Migration of the particle to the collector.3. Deposition of charged particles on the collecting surface.4. Dislodging of particles from the collecting surface.

Performance Criteria: The performance of the electrostatic precipitator depends on several factors among which the prominent are:

Characteristics of dust:

a) Particle size distribution

b) Dust loading

c) Chemical composition

d) Electrical resistively

e) Adhesive/cohesive properties

Characteristics of gases :

a) Temperature.

b) Chemical composition

c) Moisture content

d) Quantity to be handled

e) Pressure

Description: The electrostatic precipitator essentially consists of two sets of electrodes, one in the from of thin wires called discharge or emitting electrodes and other set called collecting electrodes in the from of pipes or plates. The emitting electrodes are placed in the centre of pipe or midway between two plates and are connected usually to negative polarity of high voltage d.c. source if the order if 25-100 kv. The collecting electrodes are connected to the positive polarity of the source and grounded.

The major fundamental parts of the electrostatic precipitator consist of the following:

1. Casing2. Hoppers 3. Has distributor screen4. Collecting System5. Emitting system6. Rapping mechanism for collecting system7. Rapping mechanism for emitting system8. Insulator housing

Electrical System:

For optimum functional efficiency of the precipitator, the supply voltage cloud is maintained near the flash over level between the precipitator electrodes. This can be achieved by an electronic control system which rises the output voltage to flash over level and reduces it automatically by a small amount in the event of a flash over.

Interlocking System: This system is designed for the safety of the personnel and protection of equipment during the operation and maintenance. This system will not operate unless the instructions are followed sequentially.

The system consists of rotary switches interlocks and key exchange boxes. The exchange boxes are located in control room and at prominent places on the precipitator casing. In the interlocking system, the insulator housing, inspection doors, hopper doors, HV isolating switches are provided with key interlocks.

GENERATORMechanical energy is converted into electric power the stator

windings of generator by the interaction of rotating magnetic field. Rotating magnetic field is created by field windings mounted on rotor shaft with the help of excitation system. When the shaft is rotated at 3000 RPM by the coupled turbine electric power is generated at a voltage 16.5 KV and 50 HZ frequency. Generator is filled with hydrogen gas for cooling its winding which in turn is cooled by circulating water. The voltage of such generated electricity is step up to 220kv or 400kv through transformer and power transmitted to Ratangarh GSS for Northern Grid, and different areas of Rajasthan.

6.0 million units energy is generated in 250 MW unit in a single day, out of this about ten percent is consumed in unit itself for running its auxiliary equipments like pumps, fans etc. about 3300 metric tons of coal is consumed in one 250 MW unit in one day.

THEORY Turbo generator manefactured by BHEL in Co-Operate with most modern design concept and constructional features which ensures reliability, easy and constructional and operational economicity. The generator stator is a tight construction, supporting and enclosing the stator wdgs, core and hydrogen coolers. Cooling medium hydrogen is contained within a frame and circulated by fans mounted at either ends of rotor. The Generator is driven by directly equipped steam turbine at a speed of 3000 r.p.m. The generator is designed for continuous operation at rated O/P. Temp. detector and other devices installed or connected within the M/c, permit the measrement of wdgs, teeth core, and hydrogen temp. hydrogen pressure and purity in M/C under the conditions. The Source of excitation to rotor wdgs is thyristorised D.C. supply. The Ausiliary equipment supplied with M/C superrises and enables the control of hydrogen pressure and purity, shaft sealing lubricating oils. There is a provision for cooling water in order to maintain a constant temp. of coolant (hydrogen) which controls the temp. of wdg., core etc as per loads.Technical Data:

• Apparent power 294MVA

• Active Power 250 MW

• Current 10290 Amps.

• Voltage 16.5 kV+/- 825V

• Speed 3000 rpm

• Power Factor 0.85

• Hydrogen Pr. 3.0 bar

• Rated Field Current 2386 Amps.

CONTROL AND INSTRUMENTATION CIRCLE: - STPS have divided four sections in C&I (control & instrumentation) Circle: -

1. SWAS package2. FSSS package3. ATRS package4. DDC section

SWAS [ Steam Water Analasis System ]: - Steam Water Analysis System is full form of SWAS. SWAS package is use for analysis of steam sample which coming from Boiler. There are coming nine lines from the Boiler. These nine lines go in cooling system for temperature Maintain. There are two types of cooling system, Primary cooling system and Secondary cooling system. The equipment is designed and assembled to enable the conditioning of samples of Boiler water and steam by reducing the temperature and pressure to a suitable state to enable the chemical parameters of the sample to be monitored.

Sample conditioning panel comprises: -Line Numbers: -

1. Make up drum water2. Conedensate pump Discharge3. LP Heater inlet 4. Feed water booster pump

5. Feed water economizer inlet 6. Boiler drum water 7. Boiler saturated steam8. Main steam 9. Hot well

Steam samplesForm Boiler

There are different measurements of samples of steam: -

SODIMAT: - The measurement of sodium in industrial ultrapure waters. The measurement is based on a direct potentionetric technique. Technique using highly sensitive sodium glass electrode. The difference of potential between the glass electrode and the reference electrode is directly proportional to the sodium concentration. Modern high-pressure power plants require feed water of very high purity. Safety in that sector is of great importance and the sodium measurement plays a specific role compared to pH, conductivity and silica trace. Actually sodium cations and anions are always linked. Most cations have a corrosive influence in water and vapor cooling circuits. Became of this chemical link

PrimaryCooling

SecondaryCooling

Conditioning P & T

Dry Panel

BLOCK DIGRAM OF SWAS PACKAGE

between sodium ions and anions, sodium measurement presents particularly important risk of corrosion and other effects. The SODIMAT uses a sodium sensitive glass electrode to measure sodium in a sample which has been previously conditioned to a pH > 10.

HYDRASTAT: - low-carbon steel exhibits a significantly improved resistance to corrosion it in contact with water of high alkalinity (pH 9-10).High – pressure circuits operating with the alkaline reign, therefore employ volatile alkalizing agents such as ammonia in combination with hydrazine to elevate the feed water pH to a level > pH 9.0. The addition of hydrazine serves the dual function of an alkalizing agent as well as on oxygen scavenger thus lowering the level of corrosion. The anodic dissolution of iron in low carbon steels is nominal at ph 9.5 provided the totally demineralized water is available ammonia concentrations required to reach this high degree of alkalinity would be detrimental to the copper tubes of the condenser because of dissolution of copper, thus imposing an upper limit of ph 9-9.3. CONDUCTIVITY MEASURMENT: - The electric conductivity measures the transport of electric change in any field. In metal conductors the current flows by transport of electrons where as in solution. It flows by transportation such as Na+ and Cl- which the higher transport of charges is the conductance of the solution.Conductivity is the capacity of a solution has to conduct current: -In solution conductivity is much more complicated than in conductors because several species ensure the transport of charge for instance in drinking water the conductive species registered are sodium, calcium, magnesium, ferrous cations, ferrites, phosphates and nitrate ions for slightly concentrated solution. The concentration of H+ protons and hydroxyl OH- ions can no longer be neglected in the presence of the product this. Therefore leads to a non-linear variation conductivity/ concentration.

SILICOSTAT: - Hp turbine nozzles and blades may, under the influence of high-pressure superheated steam exhibits significant capacity and conversion efficiency losses as a result of silica contaminated steam latter tends to from insoluble deposits on critical part of the turbine leading to surface roughness which, in turn, is detrimental to turbine efficiency. In order to assure optimum turbine performance continuous monitoring of silica in superheated steam, boiler water and feedwater is of the utmost importance. The polymetron silcostat has been designed specifically to complete this task.

Analyzers: -

Lines Coming from Type of Analysis

Line 1 Make up Drum water

Specific conductivity

Line 2 Conedensate pump discharge

pH, specific conductivity, cation conductivity, dissolved oxygen, sodium.

Line 3 LP heater / inlet pH, specific conductivity, dissolved

Oxygen.

Line 4 Feed water booster pump

Dissolved

Oxygen.

Line 5 Feed water Economizer inlet

pH, specific conductivity, cation

conductivity, silica,

Hydrazine.

Line 6 Boiler drum water pH, specific conductivity, silica.

Line 7 Boiler saturatedSteam

Specific conductivity, cation conductivity.

Line 8 Main steam Specific conductivity, cation conductivity, silica.

Line 9 Hot well (2 off) Specific conductivity.

The sample analysis panel comprises the following analyzers: - No. of Analyzers

Analysis 1 Single channel silica 1 Two channel silica 2 Dissolved oxygen 1 Hydrazine 14 Conductivity 4 pH 1 Sodium

ATRS [Automatic Turbine Run Up System ]: -

Introduction- All control function related to turbine are realized by Microprocessor based PROCONTROL ATRS System. This is based on user friendly programming languageP10. The system is divided in three sub groups: - 1. SGC-Oil :- Oil pumps(AOP,EOP,JOP) interlocks, automatic &

protn. Operation are realized in this group.2. SGC-Conden. & Evac . : - CEP’s & vacuum pump operation.3. SGC-Turbine :- For automatic synchronization of machine to

the grid. Procontrol requires serial data exchange confined to the electronic room(panels), process computer(monitoring) and control room.

HARDWARE The data transmission is performed with two level serial bus system- Local Bus : - Local bus interconnects all input, output, and

processing electronic modules, which is part of station. Each local bus work independently from any other local bus or Intra-Plant.

Intra – Plant Bus : - This bus interconnects its related local buses via coaxial cables. And through which Monitoring computer and diagnostic station connected. The local bus can be grouped together in the same panel or distributed in different panels. Each massage is cyclically transmitted over the local as well as intra- plant buses and transmission freq. Is selectable and can be every 10 ms.

PROCONTROL has following basic type of electronic modules: - Individual Control modules : - These implemented to control,

supervise, monitor, protect individual valves, pumps, fans etc. Modules equipped with a microprocessor, built-in l/o and dedicated control entity to control element. A serial l/o interface to the local bus to receive process signals required for interlaces & permissive logoc. Hardwired interface is also provided to control room. Modules are- AS45, AS46, AS47.

Programmable Processor :- This modules used for automation and superimposed on the individual control modules and allows to build control, protection and alarms. Module is-PR05.

Input/Output modules :- Various modules for input/output capabilities and connected to local bus. These modules can handle single, double throw contacts, thermocouple, RTD’s, milliamp signals etc. or to provide milliamp, voltage, electronic contact output signals.

LOGIC: - TURBINE PROTACTION

SN SERVICE ALARM TRIP1 Lub oil Pr V. Low 2.1kg/cm2 (2 out of Pr. Swth. Oprt.) 2 Cond vacuum V. Low -0.8 -0.7kg/cm2 (2 out of 3 vac. Swth. Oprt.) 3 HPT Exhst Stm Tmp V. Hi 480 510 (2 out of 3 T/C Tmp. Rises)4 Axial Shift V. Hi +/- 0.5mm. +/- 1.0mm (2 out of 3 Senser optd.)Protection ON:- 1) FIRE PROT.2 CH-1 (2) FIRE PROT.2 CH-2 3)ANY JOP ON & SPEED<10 RPM &SPEED RELEASE & SO/H2 DP>1.2 BAR EMER.OIL PUMP(EOP-DC) Protection ON:- 1 SLC EOP-DC CMD-51

(i) SLC EOP-DC ON & EOP AC FAIL & L.O.PR<2.1

(ii) SLC EOP-DC ON & EOP AC OFF & EOP AC DIST. & LUBE OIL PR<2.1

EMER. OIL PUMP(EOP-AC)Protection ON:- 1)FIRE PROT.2 CH-1 (2)FIRE PROT.2 CH-2(3)EOP AC PROT. ON

(i) SLC EOPAC ON & LUB OIL PR<2.1 (ii) EOP DC ON

JACKING OIL PUMP-2 (JOP-DC)Per. ON:- JOP-1(AC) OFFAuto ON:- 1.SLC JOP-2 CMD-51 (i)SLC JOP-2 ON & JOP PR.<100 &TUR SPEED<510 (ii)SLC JOP-2 ON &JOP-1 OFF & JOP-1 DIST.

(iii) SLC JOP-2 ON & JOP AC FAIL & TUR SPEED<510

Prot. ON:- 1) FIRE PROT.2 CH-1 (2)FIRE PROT. 2 CH-2

3) JOP-1 OFF & JOP AC FAIL & TUR SPEED<510Prot. ON:- 1)FIRE PROT.2 CH-1 (2)FIRE PROT.2 CH-2 3) JOP-1 OFF & JOPAC FAIL & TUR SPEED>15 & TUR

SPD<2800