RAJASTHAN RAJYA VIDYUT UTPADAN NIGAM LIMITED(RRVUNL)

SUMMER TRAINING REPORT

SURATGARH SUPER THERMAL POWER STATION ( SSTPS ), SURATGARH

Malaviya National Institute of

SUBMITTED TO: SUBMITTED BY:

Department of Electrical Engineering Anil Kumar

Maalaviya National Institute of Technology, 2008UEE105

Jaipur BATCH: E-1

CONTENTS

S.NO. TOPIC REMARK

1.

2.

3.

4.

5.

PREFACE

ACKNOWLEDGEMENT

ABOUT PLANT

PLANT FAMILIARIZATION

(i) TURBINE

(ii) BOILER

(iii) E.S.P.

(iv) COALHANDLING PLANT

(v) ASH HANDLING PLANT

(vi) GENERATOR

(vii) CONDENSER

(viii) MILLING PLANT

(ix) SWITCHYARD

CONTROL AND

INSTRUMENTATION CIRCLE

SWAS PACKAGE

ATRS PACKAGE

DDC PACKAGE

FSSS PACKAGE

PREFACE: -

A very important element in curriculum of an Engineering student is the Practical Training.

I underwent practical training at “SURATGARH THERMAL POWER STATION” from 01-06-2011 to 30-07-2011. This is a part of total 60 days training program incorporated in the curriculum of the Malaviya National Institute of Technology, Jaipur for B.Tech. course.

As I am a student of Electrical Engineering so the training at S.T.P.S. has been particularly beneficial for us. 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 and concepts of controlling of instrumentation power.

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. It is very vital trade.

ACKNOWLEDGEMENT

I wish to express my deep sense of gratitude to our training & placement officer Mr. Rohit Goyal and H.O.D. of electrical Mr. K. R. Niazi for suggest and valuable guidance for S.T.P.S. It is my proud privilege to express my sense of gratitude to Assistant engineers for providing me adequate facilities to undergo training at S.T.P.S.

I am thankful to Mr. B.P. Gautam (SE), Mr. Udaybhan Singh Shekhawat (JEN) & Mr. Sandeep (JEN) for their valuable guidance and co-operation without which it was not possible to get so much knowledge. I am also grateful to Mr. Ghanshyam Agarwal (AEN) & Mr. Ramesh Sethi (AEN) their persistent help and for providing some of the technical data.

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.

Anil Kumar

ABOUT PLANT: -

Rajasthan Rajya Vidhyut Utpadan Nigam Ltd.(RVUN) established under companies Act- 1956 by Government of Rajasthan on 19.7.2000 is engaged primarily in the business of GENERATION OF ELECTRICITY.

At present the total installed capacity of various Thermal and Hydel Power Stations owned and run by RVUN is 2086.85.

The operation and maintenance of Rana Pratap Sagar(172 MW)

And jawahar Sagar (99MW) Hydel Power Stations (owned by RVUN being shared project with MP State) is also carried out by RVUN.

With the commissioning of Unit #4 of 250MW at STPS it has become FIRST SUPER THERMAL POWER STATION OF RAJASTAN.

W Unit #1 of STPS w as commissioned on coal firing on 4.10.1998 and commercial operation of the unit was declared from 1.2.1999. The unit was dedicated to the Nation by Hon’ble Chief Minister of Rajasthan Shri Ashok Gehlot on 3.10.1999.

The foundation stone for Unit # 3 and 4STPS stage – II was laid by Hon’ble Chief Minister of Rajasthan Shri Ashok Gehlot on 3.10.1999.

250MW Unit # 2 of STPS was commissioned on 28.3.2000 and was put on commercial operation from 16.7.2000. It saved Rs.80 crores due to early start of generation. The Unit was dedicated to the Nation by Hon’ble leader of Opposition, Lok Sabha Smt. Sonia Gandhi on 13.10.2000.

The foundation stone for 250MW Unit # 5 under STPS Stage-III was laid by Hon’ble Union Minister of Power Shri Suresh P.Prabhu on 12.2.2001.

250Mw Unit # 3 of STPS was commissioned on oil 29.10.2001 and was put on commercial from 15.1.2002. The unit was dedicated to the Nation by Hon’ble Dy. Leader of Opposition, lok Sabha Shri Shivraj V.Patil on 17.3.2002.

250MW Unit #4 of STPS was commissioned on oil 25.3.2002 and has been put on commercial operation from 31.7.2002.

LOCATION OF 1500MW SURATGARH SUPER THERMAL POWER STATION (SSTPS)

The resinous project of Rajasthan, the Super Thermal Power Station, and Suratgarh is situated near village Thukrana about 27 km. from Suratgarh city in Sriganganar district. The site was considered an ideal location for setting up a thermal power station due to availability of land, water, transmission line and cheap labour.

A total land area of 5029 bighas been acquired for the power station and 12 km. long constructed from national highway no. 15 near Birdhwal railway station to plant site.

A private railway line of 17 km. has been constructed for coal supply from railway station to plant site along with private railway station at Birdhwal and at STPS site. The water availability is also good because the INDRA

GANDHI CANAL is 5 km. away from power plant. In the STPS

transportation facility is also very good.

Development consultant to the project. The civil work of the powerhouse building and township were awarded to m/s RSBCC Ltd. Jaipur a govt. of Rajasthan undertaking.

THERMAL POWER PLANT

A thermal power stat ion is a power plant in which the prime mover is s team driven.Water is heated, turns into s team and spins a s team turbine which ei ther drives an electrical generator or does some other work, like ship propulsion. After itpasses through the turbine, the steam is condensed in a condenser and recycled now here 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.

GENERAL PLANT OVERVIEW

First of all coal zone and collection of coal comes in miles by the mean of CHP (Coal Handling Plant). CHP is the biggest site of coal like belt conveyors, bunker or crusher house etc.

Belt conveyor is used to lift the coal, cleaning collection or hammering process in the Bunker or Crasher House and Stacker &declaimer device is used to store or collect the coal in coal yard.

The size of coal which enters the mill is about 25mm each. The ball and tube mill is used in the power station. The coal, which was entering in the mill,grinds in the mill up to the powdered form. This powdered form of coal sends to the boiler Furnace where this coal burns and generate heat.

Initially the liquid fuel (Diesel + Stream) is used to generate the heat. The air is also used with coal in furnace for generating the flame heat. Water flow in tube which is mounted around a wall of boiler, this water comes on the drum after crossing the Economizer because the purpose of goes on aborting heat at constant pressure and is evident by rise in the temperature. A stage reaches where water begins to boil and there is no rise in temperature at this stage stream is formed.

Burnt coal converts in to ash some one of flue gasses because the temperature of flue gasses is very high so if we went to increase the efficiency of the system these flue gasses flow in many stages like, Super heater, air preheater & Economizer.

After passing the flue gasses the temperature of steam, which was flows in super heater, is rises. When the flue gasses in the air preheater passes the temperature increases. At the last stage when the flue gasses flows in the Economizer the temperature of water which can feed into boiler dream is also increase.

After passing few stages the flue gasses taken from boiler by IDM (Intermediate Draft Fan) and send to chimney through ESP (Electro Static Precipitator). The Electro Static Precipitator which use electric force to remove the dust from the

gases steam some ash send to ash dyke threw pipes in a slurry form with the help of number of pumps.

Boiler drum is situated at the top of the furnace throw the boiler tubes which are situated in the furnace. The water is used to produce steam. First of all water comes in Economizer after this its temperature increases up to 307°c.

After this water goes in the boiler drum and heater, which are mounted on the top of the furnace, then the water flows in the tubes. These tubes are connected with the flame in the furnace. Due to heating the water converted into the steam. This steam is collected in boiler drum. The temperature of the steam is about 538°c with the help of super heater.

First of all steam flows threw HP (High Pressure) Turbine at a pressure of 150kg/cm² and there is expansion of steam in turbine at a temperature of 340°c and the pressure of 340kg/cm² and gives the mechanical work for this the rotor rotates at some speed. This steam is again heated with the help of super heater and this heated steam is send to IP (Intermediate Pressure) Turbine and the steam expand at a temperature of 200°c and pressure is 6kg/ cm². This expended steam direct send to LP (Low Pressure) Turbine and expansion of steam in this turbine is double flow.

This steam moves the blades of the all their turbines that as these blades rotates on the same shaft, which are connected to the Generator. As the blade moves are the rotor of the generator is also rotates at 3000 RPM at effective load. Thus rotation of the rotor occurs. The magnetic field results for the generation of electricity.

After this water feed into HPB (High Pressure Boiler) by the help of BFP (Boiler Feed Pump). For this the temperature of water is about 250°c. In the last stage the water is feed into the Economizer. This cycle works regularly and it is same for all units in this Super Thermal Power station.

COAL FOR STEAM STATION:-

In India, the principal sources of energy are coal amounting to over 95% of the total primary energy resources of the country. The coal reserves of obtaining in our country are of the order of 130,000 Million Tones or even more and few reserve is being located. The main area where coal mines are located easterner regions Viz.

Bihar, West Bengal, central region viz. Singrauli coal fields, Tamilnadu. Small source of coal are located in the entire country as well.

CONSIDERATION FOR THE LOCATION OF THE LARGE

THERMAL PLANT:-

The important aspect to be borne in mind during site selection for a thermal power plant availability of coal, ash disposal facility, space requirement, nature of land, water, transport facility labor, public problems, size of the plant. Large development in the thermal power generation calls for proper planning in choice of site, climatic condition, unit size, coal requirements and transport, transmission system etc. It is normal practice to consider various alternative sites for locating thermal plant and work out comparison to arrive at economically feasible location. The preparation of feasibility report for a thermal station requires study under two headings viz. area selection and site selection. The area selection study comprises the study of factor given below, which are required for the establishment of any production oriented industry. Some of the also applicable when final choice of site is made.

Supply of row materials, which is the case of thermal station are coal and water, are for extreme importance. Transport facilities to whole the raw materials viz. Coal in this case and the capital equipment. Transmission of the power produced to the local centers. A labour force of size and quality required but this will not be of ever riding consideration. In our country the migration of labour from one place to another does not pose very difficult problems. Climatic conditions has also plays an important role in area selection.

PLANT FAMILIARIZATION

TURBINE

Steam turbine is a rotating machine which CONVERTS HEAT ENERGY OFSTEAM TO MECHANICAL ENERGY.In India, steam turbines of different capacities, varying from 15 MW to 500MW, are employed in the field of thermal power generation.

Steam turbine is a device which consist heat energy mechanical energy. In India, steam turbine of different capacity varying from 15-500MW, are employed in the field of thermal power generation. The design material auxiliary system etc. Very widely from each other depending on the capacity and manufacture of the sets. Therefore the discussion in the chapter will follows the general pattern applicable to almost all type of turbines, with reference to the specific features of 210 MW steam turbine and 500 MW turbines which from the backbone of the power sector in India, here is 250 MW turbines are used.

WORKING 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 onreaction principle with throttle governing. The stages are arranged in HP, IP and LP turbines, driving alternating current full capacity Turbo generators.

When steam is allowed to expand through a narrow orifice. Reaction turbine is used in Suratgarh thermal power station. In this turbine in which some expansion of steam in fixed blade and some expansion in moving blade. It assumes kinetic energy at the expense of its enthalpy (heat energy). This kinetic energy of steam is changed to mechanical energy through the reaction of steam against the blades. After this the rotor rotates with some speed.

SPECIFICATIONS:Type - tandem compound condensing ReactionRated output of turbine - 250 KWRated speed - 3000 RPMMain steam temperature - 537 CRated pressure - 150 kg/cm

CONSTRUCTION, STEAM FLOWS:-

The steam turbine is a random compound machine with high pressure intermediate pressure and low-pressure parts and HP and LP parts are single flow cylinders and LP parts are double flow cylinder. Rigid couplings connect the individual turbine. The HP turbine has been constructed for throttle governing. The initial steam stops and control valves. The line leading from the HP exhaust going to the re-heater is provided with swing check valve, which prevent heat steam from the re-heater flowing back into HP turbine.

The steam is coming from the re-heater is passed to the IP turbine via to combined re-heater stop & control valves. Cross-around pipes connect the IP & LP cylinder. Blades are arranged at several points of turbine.

HIGH PRESSURE TURBINE

The outer causing of high pressure HP type turbine is of the barrel type and has neither other as axial nor a radial flag. This prevents mass accumulation with high terminal stress. The almost perfect rotation symmetry permits maturate wall thickness of nearly equal strength at all section. The inner casing is axially split and kinematically supported. As the pressure difference across the wall of inner casing is low, the horizontal flag and connection belt can be kept small. The barrel

type casing permits flexibility of operation in the form of short start-up time and a high rate of change of load at high initial steam condition. Inlet steam temperature and pressure is 538°c and 150Kg/cm². Rotation speed is 3000 rpm whose medium is steam.

INTERMEDIATE PRESSURE TURBINE 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.

LOW PRESSURE TURBINE

The casing of the double flow IP turbine is of their three-shell design. The shell is axial split and has rigid welded construction. The inner shell taking the first rows of guide blades are attached cinematically in the middle. The turbine has an electro hydraulic governing system blacked up with a hydraulic governing. An electric system measures and control speed and output and operates the control valves hydraulic in conjunction with an electro hydraulic governing system permits run up control of the turbine up to rated speed and keeps speed swings following sudden load shedding low. The liner output frequency characteristics can be very closely set during operation.

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 inparallel with other machines.3. Protecting the machine by reducing the load or shutting off completely inabnormal 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.

BOILER

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.Boiler is an equipment which is used to generate the steam. The steam gives a main role for generate for the electricity. Initially water entered the boiler at a temperature of 300°c and gives output temperature is 500°c of steam. For this purpose Drum, Economizer, Pre heater, Super heater equipments are used. A path of water which was comes in boiler as given below:-

Condensate water comes in the LPH (Low Pressure Heater) with the help tubes and water goes in the Dearator. Dearator is a devise which is use to remove the oxygen practical in water. Dearator water comes in the high pressure heater with the help of boiler feed pump, after this water comes in Economizer and the temperature of water 360°c and last stage water comes in boiler drum after this water flows in the tubes and converts in steam.

IMPROVED MEATHOD OF HEATING OF BOILER

The saving of latent heat of the steam by evaporation of water above critical pressure of the steam. Heating of water can be made by mixing the superheated steam. The mixing phenomenon gives highest heat transfer coefficient. The overall heat transfer coefficient can be increase by increasing the water velocity inside the tube and increasing the gas velocity. Boiler furnaces have negative pressure or vacuum because the flam has not entered in outermost area of boiler. Coal nozzle liquid oil nozzle or air nozzle rise are provide at all corners in the boilers. Here is water tube type boiler used for these tubes mounted on walls of boiler. An electrostatic precipitator is a large, industrial emission-control unit. It is designed to trap and remove dust particles from the exhaust gas stream of an industrial process. Precipitators are used in these industries-

Power/Electric Cement Chemicals Metals Paper

GENERAL CONSTRUCTION OR OPERATION

This boiler has divided by into these zones. In the zone first transfer is preheated by radiation as the flam in the zone is diffused yellow flam, which radiates much more than the premixed blue flam. As the burnt gases upward and secondary air is added.

The effect of radiation is reduced, becomes predominate as the flam changes from diffused to premix. The space marked by R+C receives heat by convention as well as radiation provided suitable heat transfer surface is including into path. The heat into zone 2 & 3 takes place mainly convention. Zone two is identifying as high

temperature and 3 as low temperature zone. Zone two is preferably for locating superheated air. Air is preheated because we want to reduce the surface area requirement. Zone three is used for economizer.

OPERATION

When the heated water comes in the drum and the flow in the heater which is situated in the bottom of boiler. Initially the liquid fuel is used to generate the heat. The air is also used with coal powder in the furnace of boiler for generate the flame heat. A stage reaches when water begins to boil without temperature change at this stage steam is formed and according to density this steam goes in the drum and then turbine.

MAJOR PARTS OF A BOILER

In thermal plant boiler consists of many parts as discussed below:-

FURNACE

Furnace is the primary part of boiler where chemical energy available in fuel is converted into thermal energy by combustion.

Dry bottom furnace is used at STPS boiler. In which selected coal of nonslogging type will be encountered in the furnace. Normally a maximum of 20% of the total ash may be collected as slag at bottom of furnace while the rest is carried away along with flue gases.

STEAM DRUM INTERNALS

Steam drum as storage tank which is used to store the steam and water. The function of the steam drum internals is to separate water and steam from the mixture generated in the furnace walls and to remove the desired solid content of the steam to below the acceptable limit.

SUPERHEATER

Super heater is main for raising the steam temperature above the saturation temperature. The introduction of advanced steam cycle in modern boilers has placed in greater burden on reheated for the 165 bar boiler is approximately 50%.

SH (Super Heater) can be classified into convention and radiation type according to heat transfer process.

AIR PREHEATER

The air preheater is now essential boiler auxiliary, because hot air is necessary for rapid and efficient combustion and also for drying coal in the milling plant.

There are two main type of air preheater in use today: static recuperative plate or tube type and the rotatory regenerative type. Here in STPS rotator regenerative type is used.

1. Heating element - Hot end, Hot intermediate, Cold endMaterials - Carbon & Corten steel2. Rotor main drive motor - 11 kW, 1450 rpm, 50 HzCoupling - Fluid coupling 11.5 fcu

2. BearingGuide bearing -Spherical roller bearingSupport bearing -Spherical roller thrust Thermostat -Burling thermostat3. Oil capacityGuide brg. Housing -25 lt.Support Brg. Housing -150 lt.4. Steam Coil AirpreheaterNumber of steam Coil APH -2 Nos per boilerInstalled position -VerticalDesign Pressure -20 kg/cm2Design Temperature -2500CWeight of One steam coil APH -1950 kg.

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.

CONDENSER

The functions of condenser are:1. To provide lowest economic heat rejection temperature from the steam. Thussaving 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 condenserThe condenser group consists of two condensers, each connected with exhaust partof low pressure casing. A by-pass branch pipe has interconnected these woe condensers. The condenser has been designed to create vacuum at the exhaust ofsteam turbine and to provide pure condensate for reusing as feed water for theboilers. The tube layout of condenser has been arranged to ensure efficient heattransfer from steam to cooking water passing through the tubes, and at the sametime the resistance to flow of steam has been reduced to the barest minimum.350% capacity condensate pumping sets are installed for pumping the condensatefrom condenser to the deaerator4 through low-pressure heaters. Two pumps are fornormal 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.

TECHNICAL DATA

Design C.W., temperature 33°c

Cold water temperature 8.31°c

Cold water flow quantity 35,000m³/hr.

No. of C.W. passes 2

No. of tubes 15,664

REGENERATIVE FEED HEATING SYSTEMIf steam is bled from a turbine and is made to give up its latent and any superheat itmay possess, to a heater this system is called regenerative, because the fluid givesup 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 250MW UNITThe regenerative system of the turbine consists of four low-pressure heaters, twogland 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 thedeaerator through gland coolers and low pressure heaters where it is progressivelyheated 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 SYSTEMThis 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 isdumped into the condenser, thus avoiding loss of boiler water. This system enablesstarting 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 steamproduced by; the boiler automatically to he condenser without affecting the boileroperation. 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 interceptingvalves to he condenser after reducing the HRH steam parameters to the conditionsapproximately 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 duringstart 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.

DEAERATERCondensate 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 foreach boiler. Two sets are run in parallel, supplying each boiler, with one pump setbeing 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 -FA1856Direction of rotation -Anti - clockwise(Viewed from drive end)Liquid pumped - Boiler Feed WaterSuction temp. -161.10CFlow rate -490 m3/hr.Efficiency -81 %Input power -151 KWSpeed 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 centrifugalpump 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 FK6D30No. of stages 6Direction of rotation Anti – clockwise(Viewed form drive end)Suction temp. 161.10CDesign flow 490 m3/hr.Efficiency 81 %Speed 5310 rpmInput power 3322 KWDrive MotorManufacturer B.H.E.L., HaridwarRating 3550 KWSpeed 1492 rpmElectrical 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 SPECIFICATIONSType EN 8 H 32Direction of rotation viewed Clock-wiseSuction temp. 46.10CSp. Gravity 0.9901

Speed 1485Power absorbed 266 KWEfficiency 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 theeight inter connected pump stage are suspended below the head piece. The pumpdischarge 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

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 FAN

In 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 highefficiencies 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 DATAApplication Forced Draft FanNo. off 2Medium handled Atmospheric AirOrientation Vertical Suction and Horizontal Delivery Capacity 105.2 m3/SecTemp. Of medium 450CSpeed 1480 rpmCoupling Rigiflex couplingDrive motor Rating 700 KWSpeed 1480 rpmFan Weight 8 TonesType 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 COUPLINGThe 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 MOTORThese fans are driven by constant speed Synchronous Induction motors.SILENCERThese fans are provided with a silencer to attenuate. Airborne noise to acceptable level.

LUBRICATIONThe 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 IOCTurbinal 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 aswill 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 DATAApplication Induced Draft FanNo. off 3Type NDZV 33 SMedium handled Flue GasOrientation 450 Top incl. Suction Bottom, horizontal Delivery Capacity 250.5 m3/SecTemp. of medium 1540CSpeed 740 rpmCoupling Hydraulic CouplingDrive motor Rating 1750 KWSpeed 740 rpmFan 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 aretwo 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 FanNo. off 3Type AP 2 17/12Medium Handled Atmospheric AirSpeed 1480 rpmRating 1400 KWFan wt. 10.8 tones

CONDENSATE EXTRACTION PUMPS

This is used to feed the condensate water into low-pressure heaters. This pump air of the vertical, eight stage, centrifugal types. In steps, three pumps are located with condenser with each boiler. In running conditions to the pumps are used to increase the efficiency of the boiler section of the plant.

E.S.P.

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

Performance of Electrostatic Precipitator (ESP) deteriorates over the years and they are not able to meet the required emission standard. In the present paper we discuss the performance of ESP’s in a power plant, which is situated right in the centre of a mega city. As the power plant is surrounded by densely populated area of the city the other emission control methods like flu gas treatment with SO3/NH# cannot be applied due to a further risk of pollution. Pulse charging methed has also limited scope of further enhancing the particulate collection efficiency of ESPS. The decision was taken to put additional unit of ESP along with existing unit of ESP. Performance Guarantee (PG) tests were carried out for the whole ESP systems. Samples were collected from the inlet and outlet of the each ESP systems. The collection efficiencies were determined for individual and for the whole set of ESPs. The results indicate a significant deterioration of collection efficiency old ESP unit at the level of (90-93)% against designed value of more than 99%. The new ESP unit, which was put ahead of old ESP unit, was operating in the range of (93-96)% of collection efficiency. The over all Collection efficiency of the system exceeded all the time more than 99.5%.

An electrostatic precipitator (ESP) is integral parts of coal based thermal power plant to control particulate emissions. ESPs are being used at DVB IP stations in Delhi. Initially BHEL-make ESPs were being used for 60 MW boiler at unit-5 of DVB IP stations. Over the years the performance of BHEL ESPs deteriorated and they are not able to meet the required emission standards. As IP station is right in the heart of city, the other emission control methods like flue gas treatment with SO3/NH3 can not be applied due to a further risk of pollution. Pulse charging method has also limited scope for improving the particulate collection efficiency of ESP. The decision was, therefore, taken to put additional units of ESP along with existing ESPs supplied by BHEL. In order to meet the particulate emission standards, DVB IP station has acquired additional set of ESPs from Alstom Power Boiler Ltd., Shahabad-585229. These ESPs are working in series with existing BHEL ESPs for 60 MW boiler at DVB IP station unit-5, Delhi. The flue gases coming out from the boiler are allowed to flow through two passes namely A and B. A set of ESPs consisting of ALSTOM ESPs followed by BHEL ESPs are fixed in each of the pass. The clean flue gases from pass A and pass B are combined and then passed through stack. The probing ports are available at the inlet and outlet of Alstom ESP. The inlet ports for BHEL ESP are the outlet ports for the two ALSTOM ESPs. However, the outlet probing ports for the A&B passes of BHEL ESPs are common after ID fan but before entry to stack.

The emission level from the power plant depends on the stable operation of boiler and efficient functioning of ESPs. Performance Guarantee PG tests unit-5 of DVB

IP station Delhi were to be carried out when the boiler got stabilized at about 60% load in the first week of March 2002. For carrying out dust loading tests at various parts of ESP systems, the services of SIMA (Sophisticated Industrial Materials Analytic) Labs Pvt. Ltd. Okhala Industrial Area, New Delhi- 110020 were acquired. Simultaneous dust loading test were carried out in a given pass at the inlet of ALSTOM ESP, at the common junction of outlet/inlet of ALSTOM/BHEL ESPs and at final out let of ESP systems. The test were conducted in pass A and B. Two sets of readings were obtained at different times on each points. Besides the measurements of dust concentration, other parameters like flue gas flow rates, flue gas temperatures, pressure drops etc. were also measured. A record of electrical operating parameters of each field in ALSTOM and BHEL ESPs were kept besides boiler side reading of unit 5.

(i) The stack monitoring parameters are listed in Table1. The measured parameters are flue gas temperature (0C); inlet/outlet and final velocities in side the duct (m/s), flue gas volume flow rates (NM3/hr), and suspended

particulate matter, SPM, (mg/ NM3). In all 12 sets the measurements have been taken at different points in the two passes A and B. The reading recorded have been depicted in figure.1 enclosed.

(ii) The electrical parameters in each field of ALSTOM ESP have been recorded during the investigation periods. Primary voltage (V) and current (A), secondary voltage (kV) and current (mA), spark rate per minute in all six fields (3 each in pass A and B) have been recorded at different times.

(iii) The operative electrical parameters in BHEL supplied ESPs, which following the ALSTOM make ESPs in each pass have also been recorded at different intervals during investigations.

Based on the observations made during investigations the particulate collection efficiency of ALSTOM ESPs and overall efficiencies of the system have been evaluated and other observations have been made. The results are summarized as follows:

(1) If one observes the volume flow rate of flue gas (QE/Hr) in table 1, the total volume of gas flow on pass (A) +pass (B)is more than the final outlet flow. A similar trend is observed through out the investigation. This shows leakage of gases in the path between the outlet of ESPs and final out let. (Ref. in the figure 1). The gas flow rate vary between 178638 Nm3/hr (49.62 Nm3/sec) to 190774 Nm3/hr (52.99 Nm3/sec). The leakage of gas varies in the range (6- 10)%. It might result in higher reading of SPM (Solid Particulate Matter) per unit of volume than

the actual, as the flue gas will leak leaving SPM behind. Pluging the leakage will result in actual observed values.

(2) The operating parameters are as follows:

Gas flow rate ≈101.6 m3/s, Gas temperature ≈ 130 0C

Specific consumption rate ≈ 0.8 Tons/MW/hr.

Electrical load ≈ 37 MW, Coal ash ≈ 40%, Fly ash ≈ 90%

≈ 29.13 gm/ m3 at 130 0C ≈ 43.0 gm/ NM3

inlet dust concentration=37∗0.8∗0.9∗0.4101.6∗3600

gm/m3

Thus, this value matches well with those measured values of SPM (mg/ NM3) and shown in table 1 & figure 1.

(3) The observed values shown in table 1 has been used to calculate the collection efficiencies of ESP systems. The dust collection efficiency has been calculated using following relations

i) Dust collection efficiency of ALSTOM ESP/BHEL ESP

= Inlet dust loading at pass A∨B –Outlet dust loading at pass A∨B

Inlet dust loading at pass A∨B

ii) Dust collection efficiency of overall system:

Inlet dust loading at pass A – Final outletInlet dust loading at pass A

iii) Theoretical efficiency of ESP may be calculated by using Deusch- Anderson equation as follows:

where,

A = Total collection area of plates (m2)

Q = Gas flow rate (m3/s)

W = Average migration velocity of charged dust particles (m/s)

Collection efficiency=1-exp(-AQ

w)

The dust collection efficiencies of ALSTOM ESPs and overall collection efficiencies have been calculated using

expressions in 1 and 2 and are shown in Table A. As one can observe from table A, the collection efficiencies of ALSTOM supplied ESPs in pass A and pass B varies between (93.48-95.74) % with average 94.60 % . While the overall collection efficiencies of the whole systems varies between (99.59-99.73) % with average 99.63 %. The designed values of dust collection efficiency of ALSTOM supplied ESPs is 93 % at gas flow rate of 148 M3/s (94 Nm3./sec). As in present case the ESP is operating at gas flow rate (∼101.6 NM3/s), the efficiency is likely to be effected if all other operating conditions remain same (equation at iii). The collection efficiencies of BHEL supplied ESPs varies between (90.60-93.86)% with average 93.23%.

The electrical parameters for all the ESPs have been noted.. There are five fields in each pass of ESP. The values of charge ratios have been kept constant. These values are 1:7 for 1st field, 1:11 for second field, 1:15 for third field, 1:17 for fourth field and 1:21 for fifth field. Only in the 1st field some back corona has developed as indicated by sparks. Otherwise most of the time, back corona has been suppressed as no sparks have been observed in other field. Secondary voltages in the five fields vary from 35 kV in first field to ∼22 kV in last field. Similarly secondary current in first field (∼ 65 mA) are higher than in last field (∼ 14 mA). Normal practice is however to set lower current in initial field and higher currents in final fields.

The variation of electrical parameter of ESP supplied by ALSTOM has been noted. As may be observed quite high secondary voltages high (>50 kV) have been maintained in all three field and both pass of ESP. No sparks have been observed during the operation, which shows the absence of back corona. As the voltage

maintained are high, a higher migration velocity is expected resulting in higher collection efficiency.

Plant load varies from 30 MW to 39 MW during the observation period. The gas temperature are almost constant; 136 0C in pass A and 130 0C in pass B. Temp. difference of 4-8 0C between airheater outlet to ESP inlet gives an impression of considerable air infiltration which dilutes the flue gases coming from boiler. Mechanical Draught is produced by Forced Draught (FD) and Induced Draught (ID) fans. FD fan, which is installed at the inlet of air preheater consumes less power and operates at near constant current rating (21 Amp and 23 Amp for pass A and B respectively). The ID fans are located near the stack, they handle hot combustion gases and their power requirem constant rating of 48 Amp in both passes. The gas flow even at lower Boiler load is more than 100% Boiler load which may overload ID fans resulting sometime puffing effect in the furnace. The opacity reading is also shown in figure, however, because of their positioning and calibration problems; these may not be relied upon.

Particle size analysis has been carried for the fly ash samples collected at the inlet and outlet of pass-A of the ESP systems. The particle Size are thus been measured at the inlet and outlet of ALSTOM ESP in pass-A. A GALAI-CIS-1 computerized Inspection system ( Laser based particle size analyzer) has been used for particle size measurements.

Table 2 and Table 3 show volume distribution of particles in different ranges at the inlet and outlet of ESP respectively. As can be observed from Table2 that around 56% of particles are having sizes less than 10 micron , a total of 44% are in larger range (18.41% in 10-20 micron, 13.31% in 20-30 micron, 10.93% in 30-4- micron and 0.49% in 40-50 micron range). At the outlet of ESP on the other hand, as shown in table7 the fraction of particles up to size of 10 micron goes up to 93% and only 7% are in the range of 10-20% micron range .The sample size was too small at the final out let for taking any meaningful size distribution measurements. However the fraction of smaller size particle (<10 micron) should still be more.

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 “ RAPPINGMOTORS”.

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 and cool the working fluid to near the wet-bulb air temperature or rely solely on air to cool the working fluid to near the dry-bulb air temperature. Common applications include cooling the circulating water used in oil refineries, chemical plants, power stations.

COOLING WATER PUMP

The motor of the CWP has following specification;Type Y1600-16/2150Out Put Power 1600KWStator Voltage 6.6KVSpeed 372rpmFrequency 50HzStator Rated Current 182AStator Connection 2YAmbient Temperature 50CInsulation Class BWeight 17500Kg

CW PUMP

Type is single stage double suction centrifugal pumpType 1400S25-1Capacity 16000m3/HSpeed 370rpmPower 1600KWWeight 35000kgHead 25mNP SHR 8.5m

The Over-all collection efficiencies for particulate have been improved by putting two ESPs in series. Further improvement is possible on adopting following steps.

♦ Plugging of leakage in the boiler / ESP system upto stack. This will minimise infiltration as well as make ID fans operation suitable to create adequate suction in the furnace.

♦ Operating the boiler at stable load with minimum fluctuation.

♦ Increasing current level of collecting electrodes of BHEL ESPs with lower current in initial fields and higher current in final field.

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 WATERThe 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 & Silica2. Dissolved Salts and Minerals · Calcium and Magnesium Slats3. Dissolved Gases · Oxygen · Carbon Dioxide4. Other Materials · Free Mineral Acid · Oil

RAW WATER AND IMPURITIES

SOURCESThe 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)

IMPURITIESThe 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

.Ionic and Dissolved 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.

COALHANDLING PLANT

Any of various ways in which coal is grouped. Most classifications are based on the results of chemical analyses and physical tests, but some are more empirical in nature. Coal classifications are important because they provide valuable information to commercial users (e.g., for power generation and coke manufacturing) and to researchers studying the origin of coal.

SPEED REDUCER

Speed Reducers feature wash down coating.

January 10, 2005 - Suited for speed reducers, Stainless Bost-Kleen™ utilizes Bisphenol-F type epoxy, which offers chemical, pressure, and thermal resistance to prevent wear and cracking caused by caustic chemicals and high-pressure wash downs as well as scratches that may occur from contact during installation and operation. Coating is USDA and FDA accepted, BISCC certified, and available on all speed reducers.

The coal handling portion of a power plant can encompass every piece of equipment from rail, truck, or barge unloading to the conveyors, crushers, and storage bins. The equipment generally operates intermittently for a set number of hours each day and does not consume a significant amount of energy. An estimated, typical power requirement as a fraction of total gross power plant output is 0.07%. Improvements to the process efficiency are limited primarily to the motors and drives. As the drives deteriorate in function and performance, they can be replaced with more energy-efficient motors. Additionally, VFDs are already used for certain applications within the coal handling equipment, but for reasons other than efficiency at low turndown. Specifically, VFDs are used to reduce excess strains on equipment, such as belts and conveyors during startup, and their application for reducing energy demands at turndown is not significantly applicable due to the intermittent operation of the coal handling equipment. Although VFDs provide more precise control of the operating equipment, which can be considered an efficiency improvement, the reduction in overall plant heat rate is not substantial.

Coal pulverizers are used to provide fine coal particles for pneumatic transport into the boiler for combustion. Fine coal particles improve the combustion efficiency of a boiler. The improvement in combustion reduces the amount of coal that must be transported and burned in the boiler and thereby reduces fuel cost and the plant heat rate. Improvements to pulverizer designs have enabled more finely ground coal and a lower primary air pressure drop through the pulverizer.Ref. 49 Such improvements can also be incorporated on older existing units, but may result in a loss in mass throughput. This reduction in throughput is generally greater than the fuel use savings from enhanced coal fineness, thereby reducing the capacity of the pulverizer. If a plant has excess pulverizer capacity, such improvements can be implemented. If the facility is switching fuels, then such upgrades are probably warranted. But, based on historical projects, this area of improvement has not yielded significant reductions in plant heat rate unless the machinery was severely degraded. The costs associated with such projects are significant.

The ash handling system presents some opportunities to switch from a water-sluicing bottom ash system to a dry drag chain system, which can save some power and water for the plant. But, in general, ash handling equipment is another area of material handling that does not present much opportunity to economically reduce auxiliary power requirements. An average of the power consumed by ash handling equipment as a percentage of total gross plant power consumption is 0.1%. The equipment operates intermittently, similar to the coal handling equipment and, therefore, is not considered a prime area of investment for plant heat rate reduction.

ASH HANDLING PLANT

This plant is used to handles the dust or ash particle that was given by the flu gases or also in furnace. The methods used for the removal of ash or dust from gases are many but, for power station application, in STPS. The electrostatic precipitator, which uses electrical forces to remove the dust from the gas steam. In ESP our different steps the process of precipitation:-

Ionization of gases and charging of dust particles. Migration of the particle to the collector. Deposition of the charge particles on the collecting surface. Dislodging of the particles from the collecting surface.

For the purpose of generates the electrical force of there the transfer or

rectifier are consists at the top of ESP.

Ash slurry in boiler is 3KM away from plant with the help of pump house.

In each unit 28 hoppers or fields are consists for the purpose of collection of coal.

GENERATOR

Generator is the electrical end of turbo generator set. It is a cylindrical pole synchronous generator. It is generally known as a piece of equipment that actually converts the mechanical energy of turbine into electricity. The generation of electricity is based on the principle of electromagnetic induction.

A generator consists of the following main components and associated

system:-

(1). Stator

(2). Rotor

(3). Excitation system

(4). Cooling system

(5). Sealing system

STATOR

The stator is the component that embodies the armature core and armature winding. It is totally enclosed gas tight fabricated structure. It is the single heaviest load in the whole turbo generator. The major part of this load is stator core. The

stator comprises of an inner frame and outer frame. The outer frame is a rigid fabricated structure of welded steel plates. Within this shell is fixed cage of girderbuil circular and axial ribs. The ribs divides the yoke into, compartments throw which hydrogen/air flow into radial ducts in the stator core and circulates throw the gas coolers housed in the frame. The inner cage is usually fixed to the yoke by an arrangement of springs to dampen the double frequency vibration inherent in 2-pole generator. The details of the stator have been shown in the figure on the next page. In large generators (500MW etc.), the frame is constructed as two separate parts. The fabricated inner cage is inserted in the outer frame after the stator has been assembled and the winding completed.

STATOR CORE

The stator is built up from a large no of vanished insulated punching or thin sections of thin (generally 0.35 mm to 0.5 mm) steel plates. The use of cooled rolled grain-oriented, loss less steel iron which the punching are made can contribute to reduction in the weight of stator core for two main reasons.

(1). There is an increase in core stacking factor which improvement in lamination, cold rolling and in core building techniques.

(2). The advantage can be taken of the high magnetic permeance of grainoriented steel to work the stator core at comparatively high magnetic saturation without fear of excessive iron loss or too heavy a demand for excitation ampere-turns from the generator rotor.

The slot ventilation holes etc. are punched out in one operation in the stampings and as such the stampings are rather complicated or accounts of holes and the slots that have to be produced. The core stampings are assembled in an inner leaved manner on core bars. The core consists of several pockets separated by steel spacer for radial cooling of the core by hydrogen. To ensure a tight and monolithic core, pressing of the punching is done in several stages and completely built, the core us help in pressed condition by mean of heavy non magnetic steel press rings which are bolted to the end of core bars as additional support is provided to the teeth portion by means of non magnetic fingers held between the core and the press ring. The press rings are tempered on the face toward the core, so that an even pressure is exerted over the end surface of the core when core bars are tighten. Copper

screens provided between the end packets and press rings reduce the end zone heating.

In order to isolate the stator body and thus foundation from magnetic vibrations of the stator core. The core bars are designed to provide elastic suspension of core in the stator.

STATOR WINDING & INSULATION

Stator core carries the armature winding where the voltage is generated due to electromagnetic induction. Each stator conductor must be capable of carrying the rated current without overheating and the insulation must be sufficient to prevent leakage current flowing between earth and phase.

The stator has a three phase double layer short core type bar winding having two parallel paths. Each coil side consists of glass insulated solid and hollow conductor with cooling water passing through the latter in case of water cooled conductors being used in higher capacity units. Water is fed to and fro the winding throw Teflon tubes.

The stator winding conductors, both solid and hollow, are transposed about

a non magnetic duct, which provide the flow path for the coolant gas in case of H2 cooled generator. In liquid cooled windings the transposed conductors are rectangular tubes. The transposition can be done in no. of ways but most commonly used method of transposition is Roebel arrangement.

The rotor is cast chromium, nickel, molybdenum and vanadium steel ingot and it is further forget and machined. The rotor forging is then planed and milled to form the teeth. Very often a hole is bored throw the center of the axially from one end to the other for inspection. Slots are then machined for winding and ventilation.

ROTOR

ROTOR WINDING & RETAINING RINGS

The rotor carries the field windings. Silver bearing copper (containing 0.03 to 0.1 % silver) is used for the winding with mica as the insulation between conductors. A mechanically strong insulator such as micanite is used for lining the slots. Later designs of windings for circulation of the cooling gases throw the actual conductors. When rotating at high speed, centrifugal force tries to lift the winding out of the slots and duralumin wedges contain them.

The end turns outside the slots are covered by non magnetic steel retaining end rings are secured to a turned recess in the rotor body. By shrinking or screwing and support at the other end by fitting the rotor body.

MILLING PLANT

Coal handling plant deals with the under loading of the coal racks, crushing of coal at different stages to stack the crusher coal at the stock pile to feed the crushed coal to the coal bunkers either directly from the rack or stockpile stacked coal through declaimer.

Coal handling plant is an important consistent of a plant. It provides crushed coal to the bunker from where it is feed to the mill in the coal mill; it gets transformed into the form of water. Coal wagons are unloaded at the wagon tippler. Here, it gets crushed to 200mm size in the ruler crusher. This is the primary stage crushing of the coal. This coal is feed to the rotatory breaker throw conveyers’ belt system. In the rotary barker the size of the coal is reduced up to 100 mm. the secondary stage of crushing this coal. This coal is either stacked at the stockpiles made for the

storage of coal or it is feed directly to the third stage. In the third stage is feed either from the stacked coal at the stockpile or directly from the rotary barker. While conveying coal to the third stage crusher, as ILMS In Line Magnetic Separator comes into the way. Here iron materials pieces etc. get separated.

The coal is feed to third stage crusher where it is crushed into size of 10 mm. this coal feed to the bunkers from where it is feed to the coal mills. To unload the coal wagons or to crush coal and to stack it and to feed it to coal bunkers. Various equipments and conveyers are installed in coal handling plant.

Some of the important equipments are listed below:-

Wagon tippler Roll crusher In Line Magnetic Separator Vibrating Feeder Apron Feeder Rotary Breaker Ring Granulator Grizzly Feeder

A brief description and working of above equipments is explained below:-

WAGON TRIPPLER

Wagon tippler unloads wagons. The sides are charged to provide at the wagon tippler. The main types of tippler auxiliaries are as

1. Rorary Wagon Tippler - Gravity & Hydraulic Clamping

2. Side Discharge Wagon Tippler - Gravity & Hydraulic Clamping

3.Wagon Pusher

4. Side Arm Charger

5.Wagon Shunting Device

ROLL CRUSHER

Roll Crushers are compression type crushers, and were once widely used in mining. They have, within the last 10 or so years, fallen into dis-favor among mining and processing companies. The probable reason is because

the large mines require very large crushed product output with minimal cost,makes the roll crusher uncompetitive. The roll crushers are not nearly as productive as cone crushers, with respect to volume, and they do have a little higher maintenance associated with them. Roll crushers do, however, give a very close product size

distribution, and if the ore is not too abrasive, they do not have high maintenance costs.

IN LINE MAGNETIC SEPARATOR

Type ‘A’ magnetic separators utilize a number of closely spaced north & south magnetic "poles" to create a powerful magnetic field capture and retain small to medium sized tramp metal contaminants. Type ‘A’ magnet circuits are ideally suited for applications such as final inspection of high quality consumer food product. Type ‘A’ magnets are available in a wide range of models each having many standard sizes to meet your specific magnetic application and budget requirements.

VIBRATING FEEDER

Vibrating feeders are in operation worldwide and can be found in mining and quarry operations, as well as aggregate, chemical, and industrial processes. Some of the more common feeder applications are in coal mining.

APRON FEEDER

TENGL Apron feeders are engineered for heavy duty operation and for primary and subsequent application stages. These custom-built machines are designed to suit individual requirement of capacity, size and material handled.

ROTARY BREAKER

A Rotary coal breaker is designed to receive run-of-mine coal. The coal breaker provides both positive control to the top size and libration of rock from coal.

RING GRANULATOR

It is a third stage crusher, called ring granulator. This crusher crushes the secondary crushed into 25 mm coal size. It is driven by HT motor 655 KW. This

motor is of the highest rating squirrel cage induction motor in coal handling plant. The crushed coal is then feed to the bunkers throw conveyers belt.

GRIZZLY FEEDER

A mill is a device in which a drum is considered which one rotates on some speed and present ball are also rotates. From this the coal is pulvorised or grained in the form of powder.

Power plant boiler fuel demand is transmitted as a coal feeder speed demand to a coal pulverizer control. A speed controller operates the feeder in accordance with the speed demand, and a position controller for a hot coal transport air damper positions the hot air damper to hold the mill outlet

temperature to a set point value and to increase or decrease damper position in accordance with a feed forward signal representing the feeding speed demand. A position controller for a cold air damper regulates the total primary air flow to a value needed for safe and smooth transport of the

pulverized coal to the boiler burners, and it accordingly acts as a process trim on the feed forward control applied by the hot damper controller.

The advantage of a ball mill may be summarized as:-

1. High output possible up to 50 tones per hour.

2. No maintains over a long period.

3. High availability.

4. This keeps primary air power requirement to minimum.

On the other hand it has some disadvantages also as listed below:-

1. High power consumption.

2. Some problem with control of coal level with in the mill.

TECHNICAL DATA:-

Application Ball tube mill

System type Pressurized direct firing

Eff. Dia. of shell 4.7 m

Eff. Length of shell 7.2 m

Shell (rpm) 15 RPM

Total weight of balls 80 tones/period

No. of lines 600 each mill

Main motor reducer gain ratio 12.5:1

Bearing type ball and roller bearing

Coupling type Fluid coupling

Lubricant oil temp. 40°c

Main motor rating 2400 KW

Auxiliary motor rating 1500 KW

MAIN PARTS OF MILL:-

Coal Feeder Coal Classifier Speed Reducer Valve or Damper

SWITCHYARD

A switchyard provides a connection point for transmission lines of the same voltage. The proposed Eastern Terminal switchyard requires approximately 4 hectares of land, However, Western Power is looking for an area of approximately

20 hectares to ensure that the switchyard can be adequately screened and to accommodate a terminal substation, in case future major development in the hillsarea trigger the need for increased power.

Current electricity forecasts indicate that it is extremely unlikely that the switchyard would be developed into a substation. Significant increases in power demand from major industrial development in areas to the east of the Eastern Terminal switchyard site would need to occur for the switchyard to be developed into a substation. Based on current State and Local Government planning, there is no foreseeable need to develop the site beyond the 4 hectares switchyard.

HIGH TENSION SWITCH-GEAR

OPERATING MECHANISM FOR HIGH TENSION ELECTRIC SWITCH-GEAR:-

Operating mechanism for high tension electric switch gear comprising hydraulic cylinder means for reciprocating a rack, a pinion engaged with the rack for rotation thereby, and a three bar toggle linkage connected between said pinion and the rotary stack of the switch for operating the switch; said mechanism being characterized by its economy, compactness, foolproof operation, safety features and power.

ISOLATORS

Elegant Design Low watt loss Switch disconnections, for manual operation. Connection: 25 sq mm box type terminal on both side for cables. Available in SP, DP, TP, and FP Mounting: Clip on DIN 35 mm rail. Can be mounted easily in any of the regular distribution boards.

CONTROL AND INSTRUMENTATION CIRCLE

SWAS PACKAGE

Steam and Water Analysis System (SWAS) shall be furnished for continuous monitoring and control of water and steam purity in the plant cycle and at other important points as specified in this specification.

The sampling system shall obtain samples from steam and water system, which shall be adequately conditioned and fed to analyzers for continuous analysis and provide parallel facility for grab sampling as specified.

The analyzer outputs shall be used for providing -

a) Continuous monitoring of various parameters using indicator with an isolated analog outputs of 4-20mA, DC for each parameter for monitoring in plant monitoring system.

b) RS-485 / Profibus output for diagnostics

c) Alarm for all significant parameters measurements, which exceed their permissible limits including those of sample conditioning system in the form of potential free contacts. The visual annunciation will be taken care of in main control room. The alarm outputs should be terminated on the terminal blocks provided in the junction box within the analyzer panel.

The offered system shall be complete with sample conditioning devices and monitoring instruments (for temperature, pressure, flow & sample) and analyzers as well as all required accessories to provide a complete and integrated sampling and analysis system as per the intent and requirements of this specification. Sample line diagrams shall be used to implement the design at system level. Vendor should be able to demonstrate the type test of sample conditioning system in his factory. As analyzer is the most important ingredient of SWAS, vendor should be able to provide proofs of collaboration with internationally recognized analyzer manufacturer from Europe or USA. Vendor to also furnish performance letters

from reputed power companies like NTPC/BHEL. Non-compliance to any of these criteria automatically disqualifies the vendor.

All piping, tubing, fittings and other sample wetted parts in the sampling and analyzing system shall be of type 316 stainless steel, except for those within the analyzers, which will be as furnished by the manufacturer.

All SWAS system components and accessories shall be from the latest proven product range of qualified manufacturers. The SWAS package including analyzers should be supplied by one approved systems vendor, who can supply the complete equipment. The vendor should have in-house capabilities to manufacture the package, such as TIG welding, NDT procedures, Hydrostatic testing upto 600 Bar, facilities for assembly & testing etc. The welding inside the SWAS panels should be done by welders approved for high pressure welding. The welders should be IBR / ASTM approved.

Vendor to be able to provide proven track record in “Coal based thermal power stations”. For this, vendor must provide a list of SWAS supplies that are made under his own brand and also manufactured in his own manufacturing plant. These supplies should have been made to Thermal Power Stations, which should be good enough to qualify him as an experienced vendor for SWAS. Vendor should have supplied such SWAS packages to minimum 10 Thermal power plants OR 20 Combined Cycle power plants Non compliance to this criteria automatically disqualifies the vendor.

All sample piping from primary root valves on process fluid lines/equipment to bulk head of SWAS panel will be arranged by the buyer. The cooling water & necessary electrical supply upto the SWAS package will be arranged by the buyer.

SAMPLE CONDITIONING SYSTEM

Sample conditioning system shall be designed and constructed to receive and condition all samples (listed in the enclosed Sample Stream Specification) as required by the respective analyzers connected to the sample streams.

Sample line to analyzer elements shall incorporate an anti-siphon design to prevent possibility of running dry because of a broken or plugged sample line

SAMPE ISOLATION VALVES &BLOWDOWN VALVES

A) For High pressure & High Temperature Lines before primary sample cooling: All sample isolation valves & blowdown valves for sample pressures of 40

Kg/Cm2 &/or above 200 Deg.C. above must be “Globe type with back seat arrangement”, integral stellited seat and welded body/bonnet design. These Valves must be IBR approved & selected as per Valves Pressure Class- ANSI B16.34-1996, Material must be suitable to withstand this high pressure and high temperature. Preformed pure graphite rings should be used as gland packing material (graphoil ropes are not acceptable). The plug & spindle should be single piece & of non-rotating type. The plug should be guided throughout its travel. The spindle should be roller burnished to ensure leakage free performance. For blow down service, valve should be provided with control cone such that the throttling area gets separated from seating area, thus enhancing the life of the seat. Needle valves / Instrument valves are not acceptable. Dilution of these specifications will disqualify the vendor.

B) For Low pressure & Low Temperature Lines before secondary cooling:

For Low Pressure (i.e. below 40 Kg/Cm2) and temperature application. Needle valves are acceptable suitable for these application. Material for these valve must be SS316.

SAMPLE COOLER (BOTH PRIMARY AND SECONDARY SAMPLE COOLERS)

All samples having a temperature in excess of 45C shall be cooled by use of sample cooler. The design of all sample coolers that handle live steam shall be validated by external authority in manufacturer’s country.The sample cooler shall use general service water (softened water) as cooling water. This cooling water is tapped from general service water whose temperature may vary from 20 DegC to 36 DegC. Cooling water pressure differential available for SWAS will be minimum 1.5 bars.

SAMPLE FILTERS

Sample particulars removal shall be accomplished by passing all samples through filters with type 316 stainless steel body. The filter design should allow the removal of filter element without dis-assembling the Filter from the line. The filter element shall be capable of retaining particles of 40 micron and larger. The filter should be located before the pressure regulator.

The filters in the secondary system shall be having blowdown arrangement for ease of cleaning of the filter element.

SPECIFICATIONS

Conductivity Analyzer

Description Specifications Vendor Response

Conductivity Sensor

Principle Resistive conductivity measurement

Measuring Ranges/ Cell Constants

0.0 - 200.0 µS/cm (k=0.01)

0- 2000 µS/cm (k=0.1)

0.00 - 20.00 mS/cm (k=1)

Relative accuracy ± 1% of full scale reading (±2 % >500 mS/cm)

Temperature Sensor

Temperature -10.0 to + 125.0 °C (14.0 to 257.0 °F)

Resolution 0.1 °C / °F

Relative Accuracy ± 0.5 °C (± 1.0 °F)

Sensor PT100

Temperature Compensation Auto / manual (reference at 25 °C)

Set Point Controller Functions

Function (switchable) limit control

P/PI control (pulse length/pulse frequency)

Integral time 0 to 999.9 minutes

Adjustable period with pulse length controller

0.5 to 20 sec.

Adjustable period with pulse frequency controller

60 to 120 pulses/min

Pickup / Dropout delay 0 to 2000 seconds

Wash cycle (If required-optional)

0.1 to 199.9 hours

Wash duration (If required-optional)

1 to 1999 seconds

Switching conductivity hysteresis

0 to 10 % of full scale

Contact outputs, controller 1 SPDT, 3 SPST relays

Switching voltage max. 250 VAC

Switching current max. 3A

Switching power max. 600 VA

Alarm Functions

Function (switchable) Latching / pulse

Pickup delay 0 to 2000 seconds

Switching voltage Max. 250 VAC

Switching current Max. 3A

Switching power Max. 600 VA

Display

LCD UV coat, backlit 14 segments display with symbols for status information

Backlight On/Off selectable with four

level of brightness control

Electromagnetic Compliance (EMC) Specifications

Emitted Interference EN 61 326

Immunity to Interference EN 61 326

Environmental Conditions

Ambient temperature operating range

0 to 40 °C

Maximum Relative humidity

80% up to 31°C decreasing linearly to 50% at 40°C

Power Supply

Input 80 to 250 VAC/DC 50/60 Hz Approx. 10VA

Main Fuse 250 mA anti-surge, S504 BUSSMANN

Pollution Degree 2

Transient Overvoltage category

II

Electrical Data and Connections

Signal Output Two 0/4 to 20 mA outputs for conductivity and temperature, galvanically isolated.

Digital communication Profibus DP

Load Max. 600 Ω

Conductivity input Screw terminal

Connection terminal 5-pin, 9-pin, and 19-pin terminal blocks

Enclosure

Dimensions 175 x 96 x 96 mm (6.89 x 3.78 x 3.78 inch)

Weight 700 g

Material ABS

Insulation IP 54 (front) / IP 40 (housing)

pH Cell And Transmitters

Description Specifications Vendor Response

pH Sensor

pH Range 2.00 to 12.00 pH

Resolution & Accuracy 0.01 pH & ± 0.01 pH

mV Range 0 to 100% or -1000 to 1000 mV

Resolution & Accuracy 0.1% or 1 mV / ± 1 mV

Temperature -9.9 to 125 oC (15.0 to 257.0 oF)

Resolution & Accuracy 0.1 & ± 0.5 oC (± 1.0 oF)

Sensor Pt 100

Temperature Compensation Automatic (± 10 oC / ± 18 oF offset adjustment) /

Manual

Set-point And Controller Functions

Function Limit / Proportional Control / Proportional Integral

(Pulse Length or Pulse Frequency)

Integral time 999.9 minutes

Pickup / Dropout Delay 0 to 1999 seconds

Wash Cycle (If required-optional)

0.1 to 199.9 hours

Wash Duration (If required-optional)

1 to 1999 seconds

Switching pH Hysteresis 0.1 to 1 pH

Switching ORP Hysteresis 1 to 10.0 % / 10 to 100 mV

Contact Outputs, Controller 1 SPDT; 3 SPST relays

Switching Voltage/Current/Power

Max 250 VAC / Max 3A / Max 600 VA

Alarm Functions

Function (switchable) Latching / pulse

Pickup delay 0 to 1999 seconds

Switching Voltage/Current/Power

Max 250 VAC / Max 3A / Max 600 VA

Display

LCD UV coat, backlit 14 segments display with

symbols for status information

Backlight On/Off selection with four level of brightness control

Emissions According to EN 50081-1

Susceptibility According to EN 50082-1

Environmental Conditions

Ambient Temp. Operating Range

-10 to 50 oC (14 to 122 oF)

Rel. Humidity 10 to 95% (non-condensing)

Electrical Data And Connections

Power requirements 80 to 250 V AC/DC

Frequency 48 to 62 Hz

Signal output Two /4 to 20 mA outputs for pH/mv and temperature , galvanically isolated

Digital communication Profibus DP

Load Max.600 Ω

pH / ORP Input BNC (1012 Impedance)

Connection terminal (1 x 3-pin; 1 x 9-pin & 1 x 19-pin terminal blocks)

Main fuse 250 mA, anti-surge

Enclosure

Dimensions (W x H x D) 175 x 96 x 96 mm Panel Mount

Weight 700g (unit); 950g (boxed)

Material ABS

Insulation IP 54 (front) , IP 40 (housing)

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.

HARDWAREThe 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 intraplantbuses 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 PROTACTIONSN 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.)