A modern power station contains numerous electrical equipment. However, the most important items are: (i) Alternators. Each alternator is coupled to a steam turbine and converts mechanical energy of turbine into electrical energy. The alternator may be hydrogen or air cooled. The necessary excitation is provided by means of main and pilot exciters directly coupled to the alternator shaft. (ii) Transformers. A generation station has different types of transformers, viz., (a) main step -up transformers which step-up the generation voltage for transmission of power. (b) station transformers which are used for general service (e.g., lighting) in the power station. (c) auxiliary transformers which supply to individual unit-auxiliaries. (iii)Switchgear. It houses such equipment which read more

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Boiler require clean and soft water for longer life and better efficiency.However, the source of boiler feed water is generally a river or lake which may contain suspended and dissolved impurities,dissolved gases etc. Therefore, it is very important that water is first purified and softened by chemical treatment and then delivered to the boiler.The water from the source of supply id stored in storage tanks.The suspended impurities are removed through sedimentation, coagulation and filtration. Dissolved gases are removed by aeration and degasification. The water is ‘softened, by removing temporary and permanent hardness through different chemical processes. The pure and soft water thus available is fed to the boiler for steam generation.Picture of a water treatment plant is shown read more

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The prime mover converts steam energy into mechanical energy. There are two type of steam prime mover viz., steam engines and steam turbines. A steam turbine has several advantages over a steam engine as a prime mover viz., high efficiency, simple construction, higher speed, less floor area requirement and low maintenance cost. Therefore, all modern steam power stations employ steam turbines as prime mover.Steam turbines are generally classified into two type according to the action of steam moving blades viz., (i)Impulse turbines (ii) reaction turbines In an impulse turbine, the steam expands completely in the stationary nozzles (or fixed blades), the pressure over the moving blades remaining constant. In doing so , the steam attains a high velocity and impinges against the moving read more

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A condenser is a device which condenses the steam at the exhaust of turbine. It serves two important functions.Firstly, it creates a very low ( By liquidation steam at the exhaust of turbine, a region of emptiness is created. This results in a very low pressure at the exhaust of turbine.) pressure at the exhaust of turbine, thus permitting expansion of the steam in the prime mover to very low pressure. This helps converting heat energy of steam into mechanical energy in the prime mover. Secondly, the condensed steam can be used as feed water to the boiler. There are two types of condensers, namely: (i) Jet condenser (ii) Surface condenser In a jet condenser, cooling water and exhausted steam are together. Therefore , the temperature of cooling water and condensate is the same when read more

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A modern steam power station is highly complex and it requires numerous main equipments and auxiliary equipments.The important equipments of steam power station are 1.Steam Generating Equipment 2. Condenser 3.Prime mover 4.Water Treatment Plant 5. Electrical Equipment 1.Steam Generating Equipment It is an important part of steam power station and it is mainly concerned with the generation of superheated steam.It includes items such as boiler,boiler furnace,super heater,economiser,air pre- heater and other heat reclaiming devices 1.1 Boiler Boiler is a closed vessel in which heat energy obtained by coal combustion is used to convert water into steam and it could be broadly classified into two (a)Water tube boilers (b) Fire tube boilers In a water tube boiler water flows through the tube read more

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The overall efficiency of steam power station is much lower and that is about 29%,it is mainly due to two reasons.Firstly a large amount of heat is wasted in condensers and secondly the heat wastage in other parts of the plant.The heat loss in the condenser is unavoidable since heat energy cannot be converted into mechanical energy without temperature difference.The greater the temperature difference greater is the heat energy converted into mechanical energy.This necessitates to keep the temperature of condenser to a minimum value.But greater the temperature difference,greater the amount of heat lost.This explains the low efficiency of steam plants. 1) Thermal Efficiency The ratio of heat equivalent of mechanical energy transmitted to the turbine shaft to the heat of combustion of coal read more

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To get an overall economy we should take care of the following factors while choosing a site for steam power station 1)Supply of Fuel The plant should be located in a place near coal mines hence the transportation cost could be reduced.If it is not able to construct a plant near the coal mines or the fuel source at least it must be considered that there are proper facilities available for the transportation of fuel ie coal to the generating station. 2) Availability of Water A large amount of water is required for the condenser for proper cooling process so there should be natural resource nearby the plant to get continuous supply of water,It could be a river,stream or lake any water source near by. 3)Transportation Facilities A modern steam power station requires the transport of coal read more

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Though the main process in steam power station is the conversion of heat energy into electrical energy,it comprises of many steps for its proper working and good efficiency.The whole arrangement of a steam power station could be divided into following steps.The whole arrangement is shown in a schematic figure given below. Coal and ash handling arrangement Steam generating plant Steam turbine Alternator Feed water Cooling arrangement 1. Coal and ash handling plant The coal is transported from different places to the station by means of rails or road and is stored in a coal storage plant.It is to use as a preserve at the time of scarcity.From coal storage plant it is transferred to coal handling plant for pulverisation.Pulverisation is the process by which large lumps of coal are broke read more

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