PRESENTATION ONIN-PLANT TRAINING DURATION:06-06-2011 to 02-07-2011 AT Kanti bijlee utpadan nigam ltd. (a jv of ntpc & bseb) By- Hari ohm Singh Kanti, Muzaffarpur, Bihar Reg no:- 09bee020
History Of Development of Plant • Vaishali power generating company ltd.(VPGCL)Formerly •Owned by “Bihar State Electricity Board” • Kanti Bijlee Utpadan Nigam Ltd.Currently • A joint venture of NTPC(51-74%) and BSEB(49-26%) • It is totally coal fired thermal power station.Features • There are two units each of 110MW installed capacity.Capacity • Installed capacity= 2*110 MW
Step-1 coal to steam Step-2 steam to mechanical power Step-3power generation , transmission &distribution
•working fluid is pumped from low to high pressure.Process 1-2 • high pressure liquid enters a boiler where it is heated at constant pressure by an external heatProcess 2-3 source to become a dry saturated vapor. • The dry saturated vapor expands throughProcess a turbine, generating power. 3-4 • The wet vapor then enters a condenser where it isProcess condensed at a constant temperature to become 4-1 a saturated liquid. • After the vapor has passed through H.P. it is reheated before passing through I.P. turbine.Process • this prevents the vapor from condensing during its 3-3’ expansion which can seriously damage the turbine blades, and improves the efficiency of the cycle
The coal is unloaded either manually or with the help ofwagon tippler into the hopper to the conveyer belt.Coal is passed through metal detectors in order to removemetals present in coal.Stones from coal is removed manually in its journey throughconveyer belt.Then the coal is passed through vibrating screen where coalof 5mm is separated from large coals.Then coal is crushed in crusher and passed through metaldetectors to remove iron particles.Coal is then supplied from coal bunker to pulverizing mill.Coal dust comes out of this mill.(KBUNL have ball mills)
At KBUNL water tube boiler is employed for steamgeneration.Fuel is burnt in furnace . The pulverized coal is dried by P.A fans andsecondary air is provided by F.D fan for pulverized coal combustion inthe furnace.Water from boiler is passed through the down comers to the bottomring header. From bottom ring header water goes to water walls forheat absorption and conversion in to steam.Bottom of furnace is open to allow ash/clinkers to fall freely in to thebottom ash hopper. And flue gas is used in economiser and reheaters.Then it is discharged with the help of I.D fan in to atmosphere.
High pressureturbine Intermediate•It is of single flow pressure turbine Low pressure turbine design with eight •Double flow design •It is also of double stages of blading. with seven stages of flow design with 6•Each stage has blading on either side. stages in front and moving and •Each stage has rear flow paths. stationary blades. moving and stationary •Each stage has•Superheated blades. moving and steam(at 1100⁰c) from •Reheated steam(at stationary blades. boiler drum enters in 535⁰ c) from H.P •Stem out of I.P. to it. turbine outlet enters turbine directly•Speed-3000rpm in to it. enters in to it. •Speed-3000rpm •Speed-3000rpm
Rating ContinuousActive Output 110 MWRated Voltage 11000+/-5%VRated Current 7220 APower Factor 0.8 laggingFrequency 50 HzExcitation System Static typeField current at rated 1335 AoutputType of cooling system Hydrogen CooledHydrogen Pressure 2 AtaNo. Of H₂ cooled 06elementsCooling medium for H₂ Soft water
Mechanical power produced at the shaft of the turbine isused to rotate rotor.Rotating Magnetic flux produced by rotor cuts statorconductor and from electromagnetic induction, electricity isproduced .rotor runs at 3000 rpm, produces 3-phase voltage at 11kv ,and of 50 HZ frequency.Oil shielded hydrogen is used for the cooling purpose ofgenerator.In case of any fault if production of plants stops then bearing motorrotates rotor shaft of turbine continuously at 65 rpm. This is because ifshaft doesn’t rotate then due to load it may bend.
KBUNL has a capacity to generate 220 MW of electricitybut only one unit is working and another is under R&Mprocess. 90 MW is generated out of 110 MW.The transmission is done through 3-phase , double circuit system.With the help of station transformer 11kv is step up to 220 kv andfed to substation.
It is the brain of any substation. All necessary steps about Transmission ,protection, Charging e.t.c are carried out in the control room.Measuring instruments of the control room:- Relay circuit •A protective device that operate during faulty condition and gives command to circuit breaker to trip. Mainly the electromagnetic induction relays are used. Fault locator By comparing voltage and current the relay measures the line impedance up to the point of fault and locate the position of fault from the previous knowledge of line impedance. Switch gear • Switches used in substation for making or breaking the electrical contacts in convenient way. There are two type of switches air switch and oil switch.
Voltmeter and ammeter•As the names imply they are used for measuring voltage and current respectively.Power meter•Used to measure the power in standard unit of MW or KW.Crt screen•A computer arrangement in which current information about transmission line is seen.Battery roomConsists of several batteries and chargers for emergencypurpose.
It consists of following equipments :- transformer •The autotransformer used in power station. It has three windings primary, secondary and tertiary. The 220kv voltage is fed as input to primary by step down 132kv fed to KBUNL as input. circuit breaker(sf6 at KBUNL) •Used for closing or opening an electrical circuit under normal or abnormal conditions. These circuit breakers are equipped with trip coil connected to relay, design to open breaker automatically tower •We have suspension type tower called as ‘A’ type tower. The peak point angle is 0⁰ to 2⁰. In this type conductor is suspended with an insulator. •Guard ring Is used to balance the capacitive current in transmission lines.
Current transformer•Used to reduce the current level such that it can be measured easily.Bus isolators•Used to isolate bus bars.Lightning arrestor•Used to protect the transmission line and connected equipment during lightening .Wave trapwave trap which changes the frequency 50Hz to 500Hz can beused for communicate between power plants.
• A controlled quantity of crushed coal is fed to each bowl mill (pulveriser) by its respective feeders and primary air is supplied from the primary air fans which drives the coal as it is being pulverized and transports the pulverized coal through the coalStep-1 piping system to the coal burner. •The pulverized coal and air discharge from the coal burners is directed towards the centre of furnace to form fire ball.Step-2 •The secondary air heating system supplies secondary air for combustion in the furnace around the pulverized coal burners and through auxiliaryStep-3 air compartments ,directly adjacent to the coal burner compartments. •Above a predictable minimum loading condition, the ignition becomes self-sustaining. Combustion is completed as the gases spiral up in theStep-4 furnace.
•The terminal voltage of alternator must be equal to the bus-bar voltage.Step-1 •The running speed frequency must be equal to the bus-bar frequency. •( Ns=120f/P ) => ( f=PN/120 )Step-2 •Where, f= frequency,P= no. Of poles ,N= speed of alternator •The phase sequence of the incoming unit must be same as that of the existing bus bar to which the generator is to be synchronized.Step-3