Uhl Hydal Project

Uhl hydal project stage second Bassi power house

Salient features:

Power channels total length = 4111m

Length of tunnels and covered flume = 3883m

Length of the open channels =228m

Maximum discharge = 25.47 causes

Tunnel section:- horse shoe type diameters 3.36m

Reservoir capacity:- 85000 c. melon

Typed:-concrete lined,

Penstock in take shape:-gradual transition from rectangular to circular section.

Penstock length (including branches) = 1163m

Size(did) =1.22m

Plate thickness =9mm to 41mm.

Quality of steel. Astm_A285-57t,grade fire box.

Haulage way capacity = 10 tones

Haulage way track:-conventional type-60lbs Rs rail.

Haulage way type:- electrically driven.

Gross head:-349.91m

Power house

Type:- R.cc Framed structure

Over all size:- 55*21*21m

Power house crane

Type:-electrically driven

Capacity:- 50 tones

Turbines

Vertical four. Four jet each.

Pelton wheel: 20700 B.H.P

Generators

16667K.v.a AC, 0.9 p.f., 11000 volts, 500rpm, 3 phase, 50 cycles.

Totally enclosed circuits ventilation, four vertical shafts

Power transformer

Single phase, 11/76.2kv Delta-Start connection, oil cooled 13 nos.

5.667*3= 17. I mva(Bank capacity)

Station transformer

30k.va 11/.415 K.V. (3nos.)

Installed capacity:- 4units(each 15mv)

=60 MW.

Total cost of the power house is = 17.29 cores.

D.C. Exciter

Type:- OVDS,15W, 130W, 115 volts, 1130amps 500rpm

Excitation system:- seprete, 30vots.

A.C GENRATOR

Type:- ADV134/55, 16667KVA 11000Volts, 874amp.

500rpm 50cycles, 12 poles, 3phase, 0.9p.f.

Excitation 109 volts. 1050amp.

Volt range= 10450-11550.

Year of construction of the generators 1964.

Brief note on UHL Hydal hydro project stage second

Bassi power house joginder nager

Distt. Mandi (H.P)

About stage 1:-

In the early year of the country major Aylward who was in such a suitable site for hydro power generation In Satluj, Beas and Raavi basins, discovers the Uhl River, antributory of the beas with natural site for generation of hydro power stage. The developmental scheme known as Uhl hydro electric scheme was conceived in 1922.

In the first stage the water of Uhl river was diverted by means of small weirs across the river “UHL” &”lambadag” near vill, Barot at an elevation about 1830m. above means see level.

The water were lead through a concrete lined tunnels 2.75km (19.25at dia) 4.02km long under the 2440m(8000ft) high ridge the Uhl river valley and Rana khad valley. These water were then led through two penstocks utilizing drop of about 518m (1700ft) in the power house at Shanan with an installed capacity 48MW (a unit of 12mw each). This scheme was completed in 1932.

UHL hydal Project stage second bassi power house

The utilization of the tail water of the shanan power house by taking the water of the power house through channels about 5.4km long consisting of tunnels, aqueduct open and covered section to a balancing reservoir at Chhaprot village having capacity of 85000 Cumes (3.01 million cues) and then giving a drop of about 350meter (1150ft) through penstocks up to Bassi power house.

Work on this project was originally stated by the Punjab Govt in 1961, subsequently on the reorganization of the state of Punjab Govt the administrative control of the project was transferred to Himachal Pradesh w.e.f.2nd may 1967.

The capacity of power plant was fixed at 60MW (4*15MW) after the completion of Shanan extension project. It proposed to have two penstock trifurcation hear the power house to feed 3*15MW units having one erected earler and powe house was missed in sep, 1970.

The existing shanan power house been renovated/augmented by PSEB in order to increase its installed capacity 210MW as Bassi power house is tail water development of shanan power house the additional water Natted for this generation at Shanan available which was proposed to be utilized for addition generation of Bassi power house.

Accordingly a scheme “ augmentation of Uhl Hydal stage 2nd Bassi augmentation 1*15MW amounting to 444.5lacs was sanctioned by the board.

The augmentation involved the installed of 2nd penstock along with associated works is presently connected to the (1st and the erection of 4th units of 15MW.) The works of bassi augmentation were started on 11th feb 1979, additional unit of 15MW along with 2nd

penstock has been completed on commercial load on 3 rd feb 1981. The expenditure of RS 5.40 cores has been increased up to date. Thus total cost of power house comes out to be about 18crores.

UHL hydal project stage 3 rd

The Uhl hydro project stage 3rd Chullah power house envisaged the utilization of the tail water of the Bassi power house along the water of the Rana khand river and Neri river through a power channel s 11.5 km long (3.1km open channel and 8.5km tunnels) giving a drop of about 299 meter. Through penstock up to Chullah power house where two machines of 50 MW each A(100MW in all) are proposed to be installed. The estimated cost of this project is RS 432crores.

Expenditure: Expenditure of Uhl hydal:- 12,61,72,305.00/- Expenditure of augmentation:- 5,40,38,329.00/- scheme. Total cost of composite scheme:- Rs 18,02,60,634.00/- Shanan powere house At Uhl River, Lambadug River, the reservoir is situated,at Brot Valley The founder is Bassi Condin Battye (1882-1933) Total cost is Rs 2.53,43,709/- First stage power generation is 48MW. Nowadays capacity of the Shanan power house= 110MW. Catchment area of both Uhl and Lambadug extend area 142sq. miles(368sq K.m)over the attitude of about 160ft. 4877meter to 6000ft i.e/

1830meter Length of catchment area =22miles(315km

Particular of turbines Turbine type:-vertical imulse Max.static head 349.9meter Design net head for rated out put-335.58me=(20.700B.H.P) Rated out put speed=500rpm. Direction of rotation=anticlockwise Runway speed at 335.58mm. 874rpm,

Net head=1422.4mm(4’.8”) P.C.D. of jets=4 Number of jets=4 Number of buckets=18 Tip of the dia buckets=1906(6”-3.04”) Main shaft dia (gen.end)=406.4mm(1’-4”) Main shaft dia bearing=558.8mm(11-10”) Main shaft dia of turbine end=406.4mm(1-4”) Main in let value=oil operated ratary. Intel value diameter=238.2mm(2’-9”) Value servometer =544.6mm(23.41”) Value opening and closing time=45seconds. Main value operating oil pressure 22.5,24.6kg/cm. Governor oil pump capacity=127.3 lt/mm. Deflector servo (double acting)=330-2mm. Deflector closing time=1.5seconds. Deflector opening time=5.0 seconds. Angulated rotating of deflector= 30degree. Shaper opening and closing time=30 seconds. Shape stock=101.6mm(4.0”) Max speed rise with full load reflection =15% Max pressure rise=15% Air compressor motor=3H.P.,1425r.p.m. Portable draying pump motor=15H.P.,2800rpm. Governor oil pump motor=15H.P,.1450rpm. Cooling water pump motor=25H.P.,1450rpm.

Power transformer To India standard 2026: 1962. Temperature rise- ON K.V. at no load H.V. 132/root 3.L.V-11. Line am pear H.V.74,L.V. 515.2. Phase H.V.=1,L.V.=1. Frequency c/s=50. Impedance volts=10% Insulation level =H.V.550Peak,L.V.75 Peak. Weight of oil = 6130 kg. Total weight= 22155kg. Quantity of oil =7230 liter.

GENERATOR:Plant dada: The plant supplied comprises of a vertical shaft salient pole. AC generator rated at 16667 KVA, 15000KW,0.9 power factor, 11KV +/-5%, 500 rpm driven by a pelton water turbine.

GENERATOR SET:

The generator equipped with a top mounted thrust bearing and a top bearing. The bearing are oil lubricated ,water cooled and have an oil level indicator and a flow indicator in the cooling water circuits.

Four breaks and jacks units and six anti condensation heaters are fitted.

GENERATOR STATOR :

The stator core and windings are housed in a fabricated steel frame made two in two section. It is built of segmental laminations punched from high- grade cold- reduce Electrical sheet steel, and is in the frame by dovetailed key bears welded to the frame. The core is divided into packets by narrow redial steel spacers, thus farming ventilating ducts leading from inside bore to the outside periphery. The spacers which are of non-magnetic steel along with core teeth, are located by spot welding to adjacent lamination.

The stator winding is of double layer lap type, comprising of turns coils laid in open slots. Each is made of 16 insulated CU strands, with transpositions to reduce circulating currents to a minimum. Each turn is insulated with two layers of mica tapes.

GENERATOR ROTOR:

The rotor poles are built up of sheet steel punching between forged steel end plates . each pole piece carries a field coil made of cu strip wounded on edge, insulated from iron. The coils are supported between top and bottom flanges of phenolic resin bounded asbestos paperboard.

In addition to the field coils, each pole has a pole face winding of round CU bars. The salient pole pieces are mounted on a rotor body comprising four rolled steel disk folded together to form a single rigid mass. The outer periphery is machined to produce slots for attachment poles.

GENERATOR SHAFT SHAFT :-

It is attached to the upper most rotor disc, and is in two parts. The lower part of the shaft is coupled to the top of the rotor by a flange with bolts and redial keys. The uppermost of the shaft is bolted to the lower part by flange, and it carries the exciter armature and permanent magnet generator rotor. Both shafts are of forged steel and have a 3.1/2” dia. Axial hole.

EXCITER:-

It is mounted on upper part of the generator shaft. The exciter is self ventilated open ty0pe, operating in junction with the automatic voltage regulating equipment change over links are fitted below the exciter support to enable the generator, slip ring voltage to be reversed to equalise slip ring wear.

GOVERNOR GENERATOR:-

It supplied the governor drive motor at frequency proportional of the speed of the set. The permanent magnet poles are fitted with a winding to permit demagnetizing it is mounted above the dc exciter, open ventilated and is very easily rated.

OVER SPEED DEVICE:

It is mounted on top of the generator shaft. It has two sets of closing contacts.

TECHNICAL DATA

Generator:

KVA:16667

KW: 1500

Output voltage: L 11KV+/-5%

Phase:3Ø

Frequency:50 cps

Poles:12

Speed:500 rpm

Stator resistance per phase at 22 c: 227801 ohm

Stator resistance field winding: y

Flywheel speed:874rpm

Synchronous reactance:0.82 ohm

Transient reactance:0.236per unit

Sub transient reactance current: 950amp

COLLECTOR AND BRUSH GEAR:-

The slip rings machined from milled steel plates and shrunk to a mica insulated steel Steve mounted on the upper part of the thrust bearing collar there are parallel brushes mounted on each collector ring.

BEARINGS:-

The mechel type bearing comprise a forged steel thrust collar, with highly polished bearing surface pressed on the generator shaft, and bearing on the ring of white metal faced on the thrust pads.

The guide bearing consists of 12 white metals pad caries on a support ring. Each pad pivots on the end of a screw passing through the support ring.

The bearing parts are immersed in the oil cooled by water passim through the four plug in the type collars to prevent the flow of shaft current through the bearing ,the thrust pads retaining ring is insulated from the floor of the bearing housing.

BRAKES & JACKS:-

The generator brackes are foir”ferdo” lined shoes, which pressed against a polished track on bottom disc pf the rotor. Each brake shoe is mounted on a vertical position in a cylinder. The brakes are operated by compressed air, monitored by a pressure switch. The brakes are also used for lifting the rotor for maintenance purpose. High –pressures oil from the portable oil pump provides the pressures to lift the rotor , which can be hold in the

raised position by a helical locking sleeve, which engages, with a fixed sleeve on each unit. Locking screws are provided as an extra safe guard.

DESCRIPTION OF PLANT

POWER STATON:

Location 5km from Jogindarnagar (H.P)

Down stream of Shanan powerhouse.

The elevation of m/c is at an elevation 2966’-0”-and tailrace channel which has its maximum water level at 2966’0”- discharges into the river. The station of the multifloor type and accesses to it is from main entrance towards fourth unit, adjacent to which is the loading bay.

The generator floor is at elevation of 28982’0”. Access to this floor is through main entrance on the left side of the powerhouse facing the main stream. In the main m/c hall are located the turbine and generator gauge panels and amplifying sets extra. Adjoining to the m/c hall on the same floor is the control by which houses the control equipment and the hydraulic panels. There are hatches for liner dismantling and transformer untanking and for the main value. Cable to the T.G panel is taken through the value of the main hall. Stairs are provided on this hall for getting down to the turbine floor.

The turbine floor is an elevation of 2969.5’. on this floor are located the governor servo- meter, actuator, strainers, pumping sets pressure receiver, co2 equipment and air compressor, various control valves are located on the wall in front of the value fit there is a wide access passaged with leaves to the turbines pit through the generator plinth of each unit.

On the down stream side of the turbine floor is a service gallery at an elevation of 2965’ which houses the colling water pumps at the first unit end of the station there is a hatch 8;sq. on the floor along elevation of each unit for removing the runner during underneath dismantling. Rails for the trolley this track and taken out through the hatches on the generator floor at the other end of powerhouse.

Stairs are provided for access from service gallery to turbine floor, there are opening for bus bar chamber in the downstream wall beneath generation floor for taking cables in cable gallery adjoin the service gallery at the same elevation. The tailrace pit is 14’-14” dia and the discharge runs along a 8’ wide opening into the tail race channel which is at an elevation of 2953’-0”.the raw bottom of the jump being and an elevation 2946”. Beams and rails are provided in the tailrace channel under heat dismantling of runner.

The valve pit of turbine floor has its floor level at elevation 2959”-7”. And accumulates the main inlet rotator value its servo meter and other ancillary equipment associated with it. There are trenches and drainpipes connecting the valve pit and tailrace for drainage purposes. The value pits covered by checker plating on turbine floor. Flow meter tapings are taken from penstock to the valve pit.

Access stairways are conveniently placed to link all floors.

A travelling crane is installed having a capacity of 50 tones with an auxiliary hoist of tones. There are used for handing the machines are also auxiliary equipment’s.

TURBINES:

The peloton turbine is of the vertical type with four jets and consisted of the following main items.

Distribution piping:

It is constructed of electrically welded steel plate and is circular in cross-section, with three way pieces for entry of water to nozzles, tapings are provided o the distribution piping of the drain valve, automatic bypass valve, pressure gauge and pressure relay. All these tapings being downstream of main inlet value- tapings on the upstream of main valve are isolating valve for high.

PIT LINER :

This is cylindrical structure of electrically welded stall suitably. It is made in quarters and the four pieces are welded together at site. A box like structure with an opening in pit liner is provided for entry of the distribution piping nine pieces.

Air piping is welded to the end of the boxes to avoid formation of vacuum in the pit. Allowance, on the former. It also carries the pressure relief disc, penstock drains dispersion and has piping fro various drains and braking jet.

TOP LINER & BRAKE SUPPORT:-

It is a conical fabricates structures of electrically welded steel flanges in the two halves having a close box like section on the top. The top ring is machined for location same brackets which carries the main breams for the generator brakes and the runner support beams, and also the air seal for the generator.

At the bottom this structure is support on six-1 beams placed radically and welded to a circular pare. The inner cylinder carries a ring for supporting the turbine guide bearings. The bottom and top cover have been suitably curved to avoid water falling from jet after in pinging on the buckets. The bottom rings at the shroud has a vertical clearance of 5/8” between the runner flanged so as to allow for jacking. Suitable opening has been provided for the deflector roads, the access passage and the connecting roads and or various pipes.

DEFLECTOR GEAR & LINKAGE:-

The Governer servomotor through direct linkage controls the deflectors of all the 4jets. The deflectors, which are installed behind the mount of the nozzle rapidly enter the jet and deflect it away from the wheel, which is followed by the movement of the spears, thus regulating the turning at different load demand.

The deflectors are cost 10% chromium stainless steel and derive the motion through deflector rods that are connected through levers and connecting rods to the servomotor crank. Connecting rods have left and right hand threads for length adjustment.

The deflectors are so positioned that with the deflector servomotor and linkage the fully closed position, the center of the deflector tip must be on the center –line with deflector servomotor on the stalk an don’t on the deflector mechanism. The deflector has been designed so that when m/c is running under varying load condition the deflector tip is always clear of the jet dia. The angular movement of deflector is 20 degrees.

The deflector rods that pass through the top cover are to be vertical and the posts in the top cover plates are to be located and doweled at site. The deflector rod has3 bearings 2 at the bottom in the nozzle body and 1 in the pot in the top cover plate. Grease connections for lubrication to each of the bearing are provided . the fork- and – lever connects the cranks to the connecting rod using a bushed pin for lubrications.

A gap of 3/8” has been provided for vertical adjustment of the servomotor crane to suit the centerline of the fork ends at site. To allow for 5/8” jacking of the shaft and the runner with the deflectors in the closed position, a clearance of ¾” has been provided between deflector head and runner/

SPEAK SERVOMOTOR:-

The spears are operated their own servo motors which in turn are operated by corresponding distributing valve by action of the deflector shaft through a deflector cam and a return motion cam. The spear servomotor is of the internal type housed inside the

nozzle body. The servomotor takes place under action of high pressure, which is taken by pen stock and compression spring.

There are 8 radial vanes inside the nozzle body, stream- line for smooth flow through which pass various drillings for the oil an water supply , the return motion cable an drains etc. the spears and the nozzle are accurately shaped. The spear tip is of stainless steel I screwed at the end of the nozzle an thus can be replaced whenever required. The tails cover of the servomotor in semi elliptical in shape and are screwed to back of the servomotor body.

SHAFT AND MAIN SEARING:-

The main shaft 16” dia is of best special semen’s martin steel with forged bearing collar and solid forged coupling flanges. Board throughout its full length to ascertain soundness. This is used for underneath dismantling of the runner. A collar below the alternator end flange is used for supporting the shaft and runner on the runner support beams.

The turbine guide bearing is of the submerged self-lubricating type. The combined bearing support and shell is in halves, with heavy joint flanges rigidly bolted and doweled to the bracket provided on the top cover. The shell is lined with anti-friction white metal with oil circulation grooves, pump intakes and thermometer packets.

The oil sump (401) is located round and below the self-lubricating bearing and is housed in the top cover. An opening in liner cylinder of the top cover is provided for draining oil from the sump.oil is circulated through viscous action by the pump unit lactated in the shell, the oil is drawn up from the oil sump (401) into the circumference grooves and fed into the vertical slots, it then lubricates the bearing and discharges from above the shell to over speed back into the sump.

The bearing shell is cooled by a flow of water taken from the main cooling water system. The cooling water flows through valve (492), and is led into the exhaust of cooling water system.

An oil sump level dipstick (409) is provided . the beating shell is drilled to receive a mercury is shell thermometer (38-7a), with two sets of contacts on the turbine panel. The two sets of contacts are for alarm and shut- show purposes. The bearing is provided with continuous oil circulation and water cooling the turbine is in operation and is protected against emergency running conditions.

RUNNER: -

The runner is a one piece stainless steel casting the buckets being integrally cast with the laid in transverse keys for transmitting the torque.

BREAKING JET:-

The breaking jet nozzle is connected to the pit line and directs a jet of water on to the runner wheel in the reverse direction to the main jets, it is operated by high- pressure water of the main pan stock through an isolating valve and automatic breaking jet control valve, which is operated by solenoid operated distributing valve. The breaking jet comes on when the turbine push button or emergency stop push buttons are pressed.

The breaking jet is stopped when the speed of machine has dropped to about 50 R.P.M. to prevent the machine ultimately turning in the reverse direction. When the jet is on there is a lamp indication on the turbine panel. The breaking jet is interlocked with the main rotary valve and does not come into operation locker with the main rotary valve and does not come into operation unit the valve is fully closed.

MAIN VALVE:-

The main inlet valve is of the rotary type and is designed to open under balanced conditions and close in an emergency against full flow. The valve consists of main body, which is in halves bolted together, and door, which is one piece and has grunions bolted on to it.

The main body is made of cast steel and is reinforced with flanges and ribs. Heavy flanges are provided at the ends with rubber seals for connection to the pen stock and dismantling joint. Bearing housing are provided for supporting the bearing and grunion seals. Stainless steel searing are welded to the body to the sealing surface. The valve door is made of cast steel and is supported in the valve body by the grunions about which it rotates in the closes position , the downstream portion of the door form spherical sealing surface. When the valve is open the door presents a smooth cylindrical bore.

The service seals is at the downstream end of the valve , while the isolating seal list at the upstream and of the valve., the is fitted with a dismantling joint, however when tightened forms a rigid connection between the valve and the distribution piping making movement impossible.

The horizontal grunions carry at one end a strong steel crank through which the servomotor force is applied to the valve.

The main valve is firmly mounted upon strong feet and supported on concrete plinths, which are anchored to the foundations. An air release cock priming value and drain valve is fitted on the value body.

SERVOMOTOR:-

The oil operated vertical servomotor consists of a flanged and ribbed fabricated steel cylinder with bolt on end covers. The covers on the top incorporate gland packing and a bush through the steel piston rod passes. The rod is screwed and welded into a steel piston that covers two piston rings.

On one end of the piston is screwed a distance place for adjustment the stocked. The other end of the rod is threaded and carries a forged steel eye which is bushed. The fork end of the rotary valve operating lever is rigidly locker to the piston eye by pin. The servomotor base plate, on which the servomotor pivots is rigidly anchored onto the valve pit flue by long foundation bolts buried in the concrete.

The valve servomotor which is double acting is oil operated oil is supplies from the pressure pumping set through isolating valve which is always open to solenoid operated distributing valve. Oil admission to the opening side or closing side of the distributing valve is controlled by solenoids. A timing diaphragm o the opening side of servomotor regulates the flow of oil. The closing and opening time of the rotary valve is 45 sec.Exhaust oil from the distributing valve goes into the pumping set through isolating valve.

CONTROL SYSTEM BYE-PASS VALVE:-

It is held in the closed position position by pressure water from upstream of the main valve door, acting on the smaller diameter of the operating piston. Water pressure is admitted to the larger dia of the piston by the solenoid –operated valve, which open when is energized. This overcomes the closing force and open the bye-pass valve at a rate determined by diaphragm.

When the solenoid has fully operated, the turbine panel indicates limit switch break the contact and the opening of bye-pass valve. The bye-pass valve closed when the solenoid isenergised connecting to the exhaust. The bye-pass valve opening is the first step in the opening sequence for the inlet valve and its closure is the last step in the closing sequence.

Servomotor:

It is operated by an oil operating distributing valve. This applies oil pressures to either side of the servomotor position, whilst connecting the other side to exhaust. The distributing valve may be either hand operated or electrically operated means of two solenoid. To open the main valve, is energized via pressure relay and once in the open position, limit switch de-energized. To close and limit switch perform similar functions. The armature of the corresponding closing solenoid balances that of. But to prevent creeping of the distributing valve a spring catch inert small retaining force in the open and the closed position, whether operation is electrical or manual.

OPENING SEQUENCE:-

Pressing the push button to open the main valve energized a relay and the opening of the main valve is carried out in the following stages:-

On pressing the main valve open button energizes solenoid thus admitting water pressures to open the bye-pass valve. This is also admits water pressure to the opening side of , and also starts preparing the circuit for energizing.

When the pressure in the distribution piping reaches 430 LBS/m2, the contact closes to energies. When is energized the closing side of the seal drops to 50 IBS/M2 the contact energizes. This opens the distributing valve by admitting the oil pressures to the opening side and the main valve opens.

CONDITION DURING SHUT DOWN:-

The following are the normal conditions during shut down. They also apply when the m/c is being started for the first time. The auxiliary 400v-ac supply from the outside line must be available for the auxiliaries.

There is water in the penstock down to the main inlet valve, which is shut. The bye- pass valve is shut & the pressure in the penstock is indicated on the pressure gauge.

When valve is closed the cooling water pumps may or may not be shut down according to the requirement for the other sets. The auxiliary pump maintains the oil pressure in the governor oil receiver.

The oil inlet valve is closed. The air compressor set automatically maintains air pressure in its air receiver. The governor speeder is in the no- load position.

HARD CONTROL:-

When turbine is being commissioned or re-commissioned after an overhaul, it should be started by hand control i.e. the separate devices are operated by hand rather than by an impulse from turbine panel.

When starting up for the 1st time, several checks should be made when at speed before taking any load. Further checks are required before the m/c considered to be commissioned.

The starting and shutting down sequences are given below:-

STARTING SEQUENCES:- a) Items of generate equipment such as heaters and jacks are not mentioned.b) Remove locking pin from rotary valve.c) Start the main governor oil pump.d) Open the bye-pass valve.e) Open the oil inlet valve.f) Check the stroke limits.

SHUTTING DOWN SEQUENCE:- a) Remove the load by a lower speed.b) Close oil inlet valve.c) Close the main inlet valve.d) Stop the main governor oil pump.

HAND CONTROL OF GOVERNER:-

Hand control of the deflectors via the hand wheel on the servomotor is only to be restored to in an extreme emergency, because speed control is virtually impossible unless the load is very steady, and also because the entire safety device are in operation.

During normal service apart from the periodic stroking of the deflectors. When the m/c is shut down ,the hand wheel and its clutch pins are used to look the deflector’s shut when oil pressure is not available.

To change over from actuator to hand control without shutting down these, unload the m/c, screw the branches split nut forward as far as it will go, and engage the clutch pins, hold the lock nut and ratite the hand wheel to ratite this. To start up under hand gear control, close and open before engaging the hand gear. To change over from hand control to actuator control. The hand gear is intended for checking the freedom of the deflector gear. When the set is on hand control then device will not be operated. When the m/c is running with hand gear control the pendulum motor should disconnected to prevent the pendulum running dry.

ALARMS:

The following conditions do not shut down the machine, but the alarm sounds and indication is given of the individual fault on the turbine panel

1. Over speed devices.2. Rotary valve failed to close.

3. Rotary valve failed to open.4. Turbines guide bearing temperature high.5. Air pressure low.6. Turbine bearing water flow lowq.7. Governor oil pressure low.8. Governor oil filter blocked.9. Auxiliary governor oil pump running.10. Thrust bearing temperature high. Stator air temperature high.11. Air cooler water flow low.12. Generator bearing oil level low.13. Generator bearing oil level high.14. Co2 released.15. Shut down relay operated.

LAMP INDICATIONS:-

The following conditions only give rise to lamp indications on the turbine panel.

a. Rotary valve in transit.b. Rotary valve closed.c. Bye-pass valve open governor oil main pump running.d. Cooling water pump no. 1 running.e. Cooling water pump no.2 running.f. Cooling water pump standby running.g. Breaking jet operating.h. Generator breaks on.i. Generator heaters on.j. Set on bars.

POWER TRANSFORMER :-

The principle of the transformer can be explained by means of faraday’s law electromagnetic induction. Faraday’s law states that- “ electromotive force (e.m.f) is induced in a closed electric circuit whenever there is change in magnetic flux linkage of that circuit” “ or the induced e.m.f is proportional to the rate of change of flux linkage”.

The direction of the e.m.f. is given by the Lenz’s law:-

“The direction of the induced e.m.f. is such that at every instant it tries to oppose the case of induction”.

A transformer has a closed magnetic circuit called core. Two more winding are placed on the core, one of the winding called primary winding is supplied with alternating voltage of power frequency (50 Hz), the primary winding takes no- load current from the supply and set- up alternating magnetic flux of 50 Hz the core. As the secondary winding also placed

on the same core the magnetic flux linkage with the secondary winding also changes continuously at a rate of 50 Hz. There by e.m.f. is induced in the secondary winding induction principle. The e.m.f. induced in the secondary winding has the same frequency as that the magnetic flux and primary exciting current however the e.m.f. in a direction opposite to applied voltage.

LAMINATION OF THE CORE:-

The core is laminated to reduce on losses the eddy current losses due to the eddy current circulating in the core are proportional to square of the thickness of the lamination is reduced eddy current losses and heating of core reduces.

The lamination is made of in the cold rolled grain oriented silicon iron sheets. The surface of the laminated on is provided with coating of insulating varnish or insulating oxide layer to prevent eddy current burs and sharp edges should be avoided core bolls should be fully insulated to prevent continuous path to circulating currants and heating due to hysterias lass.

PROTECTION OF TRANSFORMER: 1. Buchhlelz relay:- this relay operated when the oil level is low, the temperature of the

transformer is high and the gas is formed the transformer.2. Winding temperature high:- when the winding temperature is high the relay is

operated.3. Oil temperature high:- when the oil temperature is high relay is operated and give

signal forward.4. Differentional protection above 5MVA.5. Earth fault protection.6. Lighting arrestor:- license of general electric 4.5A. thyrite magnet valve are ester unit

LT modal 2 HD-36 max., rating 36 KV, rms made in India , three no’s of each unit.

ELECTRIC MEASUREMENT INSTRUMENT:- I. MultiMater are avometer:- two type multimeter (a) analogue type. (b) digital type.

The millimeter is used measure IC/DC current resistance voltage etc.II. Clamp meter/ tong tester:- it is also used for the measurement current, voltage, and

resistance etc.III. Volt meter.IV. Ampere meter.V. Power factor meter/

VI. Phase shifting transformer.VII. Verie.

VIII. Oscilloscope.IX. Phase sequence meter.X. Single phase veric.

XI. Earth maggar(for earth fault test.)XII. Rheostat.

MAGGAR:- The insulation resistance of winding is a function of type:-I. The permanent magnet generator is attached to the alternator shaft. This generator

produces a 3- phase alternating supply at the frequency of the main m/c. this is supplied by the alternator manufacturer.

II. A specially designed synchronous reluctance motor receiving its current form the P.G.M and driving the pendulum.

III. The actuator 65 including the pendulum distributing valve and return motion devices.

IV. A double acting servomotor operating through a regulating shaft.V. The necessary control piping, solenoid operated valve and pressure operated valve.

VI. The deflector gear including , deflector rods, connecting rods and lovers etc.VII. The distributing valve which supplies oil to the spear servomotor.

VIII. The return motion gear & cams, which relates the positions of the deflector & gear,IX. The pressure pumping set with its pump, motors & the pressure receiver.

CONDITION DURING SHUT DOWN:-

The following are the normal conditions during shut down . they also apply when the m/c is being started for the first time. The auxiliary 400 v-ac supply from the outside line must be available for the auxiliaries.

There is water is the penstock down to the main valve. Which is shut. The bye-pass valve is shut & the pressures in the penstock is indicated the pressure gauge.

When value is closed the cooling water pumps may or may not be shut down according to the requirement for the other sets. The auxiliary pump maintains the oil pressure in the governer oil receiver. The oil inlet valve is closed. The air compressor set automatically maintains air pressure in its air receiver. The governor speeder is the no-load position, assembly of insulating material in general it varies directly with conductor surface area. The value of insulation resistance also varies universally with amount of moisture in the insulation and the amount of solvent left in the bounding varnish of the connection.

Insulation test are carried out normally using a maggar which polarization index value are required must be capable of supping a steady voltage for of minutes. The result

obtained using DC test method are affected by the general condition of he surface of the winding as well as by the leakage through mai9n insulation interpretation of the result can difficult if contamination is present for the region the core caring out the test. The surface of the binding should be examined to make sure that are clement dry and not contaminated of moisture oil, salt, carbon dust or other foreign matter.

SAFETY PRECAUTION FOR TESTING:-

Before attempting any insulation resistance test it is essential to earth the frame of the machine and any part of the winding not being tested. Dry insulation resistance tests is capable of holding and electric charge for several hour after the removal of applied voltage fro region of both safety and accuracy. For section under tested adequately both before and after the application of best potential.

Polarization index:-

The measurement insulation test of winding normally increase with time of the DC test voltage. The increases is usually repeat for first hour and their after the slop of the curecve with time study for nest 10 to 30 minutes. The increase is function of absorption characteristic of the insulation and hence its general condition on majority of winding the valve reached in 10 minutes will be greater the 90% of steady stage reading. The polarization index (R1) to the insulation resistance after 10 minutes (R10). I.e. polarization index = (P1=R10/R1)..

ELECTRIC MEASUREMENT INSTRUMENT:- XIII. Multi-meter are a voltmeter:- two type multi-meter (a) analogue type. (b) digital

type.The millimeter is used measure IC/DC current resistance voltage etc.

XIV. Clamp meter/ tong tester:- it is also used for the measurement current, voltage, and resistance etc.

XV. Volt meter.XVI. Ampere meter.

XVII. Power factor meter/XVIII. Phase shifting transformer.

XIX. Variac.XX. Oscilloscope.

XXI. Phase sequence meter.XXII. Single phase Variac.

XXIII. Earth meggar (for earth fault test.)XXIV. Rheostat.

MAGGAR:- The insulation resistance of winding is a function of type:-X. The permanent magnet generator is attached to the alternator shaft. This generator

poroduces a 3- phase alternating supply at the frequency of the main m/c. this is supplied by the alternator manufacturer.

XI. A specially designed synchronous reluctance motor receving its current form the P.G.M and driving the pendulum.

XII. The actuator 65 including the pendulum distributing valve and return motion devices.

XIII. A double acting servomotor operating through a regulating shaft.XIV. The necessary control piping, solenoid operated valve and pressure operated valve.XV. The deflector gear including , deflector rods, connecting rods and lovers etc.

XVI. The distributing valve which supplies oil to the spear servomotor.XVII. The return motion gear & cams, which relates the positions of the deflector & gear,

XVIII. The pressure pumping set with its pump, motors & the pressure receiver.

CONDITION DURING SHUT DOWN:-

The following are the normal conditions during shut down . they also apply when the m/c is being started for the first time. The auxiliary 400 v-ac supply from the outside line must be available for the auxiliaries.

There is water is the penstock down to the main vlave. Which is shut. The bye-pass valve is shut & the pressures in the penstock is indicated the pressure gauge.

When value is closed the cooling water pumps may or may not be shut down according to the requirement for the other sets. The auxiliary pump maintains the oil pressure in the governer oil receiver. The oil inlet valve is closed. The air compressor set automatically maintains air pressure in its air receiver. The governer speeder is the no-load position.

Permanent droop signal contributes gate V/s speed characteristics to the system virtue of this the machine accepts load when the frequency decrease and rejects load when the frequency increase. Amount of the permit drop which adjustment from 0 to 10% decides the slope of charactertics line in relation to gate position, in other words permanent droop means speed regulation . at 10% droop a machine operating at 50Hz will accepts full load either if the frequency decrease by 10% or if the speed setting is raised to 55Hz (50HZ +10%) so as open the gate fully, however if the grid the grid frequency is 48Hz speed setting will have be raised to 53Hz (48+3) only.

The summing amplifier out put is amplifier out put is amplifier in a booster amplifier and then applied to a electro- magnetic transducer (EMT) located in the hydro- mechanical

cabinet. It is the linking device between electrical and hydro mechanical sections. The EMT actuating the hydraulic amplifier convents the electrical signals into the proportional mechanical mechanical movement . the movement when amplifier hydraulically results in the movements. The movement when the amplifier hydraulically results in the movement of the main distributing valve which in turn imparts oil to the servomotor for controlling the gate movement .

Under steady state conditions governor provides balance currents of 0 Ma the EMT. In the event negative current for closing of the gate and in the event of frequency falling or rising command it provides proportional positive current for opening the gate once the gate acquires new position the out put current resent to 0 miles ampere. Under action of permit droop signal under dynamic conditions out put current can very in the range of -60 to + 60 miles amp. The relay control circuits enables the turbine to be started. Stopped and protected.

Optional features:-

Speed seating motorized potentiometer 6.5s.

Motor drive facilitates remote control of the potentiometer and makes the governor suitable for auto –synchronizing. As this is used exhaustively for synchronizing a slow speed (1rpm) drive motor has been used the speed signal.

Gate setting motorized potentiometer 65G;-

Here also the motor drive facilities remote control and makes the governor suitable for obtaining faster loading and unloading for the machine a higher speed (3 to 6rpm) drive motor for been used. The gate setting signal acts on the summing amplifier through the permanent droop circuit.

Zero speed deflector:-

This feature enables automatic removal of the generator brakes when the machine comes to a stand still following a shut down .

Synchronizing:-

When the machine operating study on governor control operate speed seating raise/lower switch on the control desk. USB to match the generator frequency also match the generator voltage with the grid voltage a synchronizes:-

Loading:-

a. Raise the gate limit with the help of gate limit raise/lower switch corresponding to the required generation.

b. Raise the gate seating with the help of gate seething raise/ lower switch.

Stopping:-

a. Turn start/stop switch to stop.b. Observe that the gate limit lower to minimum position and gate follows the gate

limit.c. Observe that when gate close to no load position the generator barker tripped.d. Observe that gate seating potentiometer (65g) homes to minimum position.e. Observe that eventually the aching stops and some delay the generator breaks are

released.

Synchronous condenser operation:- 1) Start any synchronize the machine as per the procedure already described.2) Turn generator / synchronous condenser operation switch to “synchronous

condenser” and observe that gate fully closed and gate seating potentiometer’ sets to minimum while limit remains synchronized.

3) For shut down control switch to “ generator operation” and observe that the gate open to no load position. Further stop procedure is same described earlier/

Circuit breaker:-

H.V circuit barker:- the circuit breaker can be classified on the basis of rated voltage circuits barker below rated voltage of 1000v is called high voltage circuit breaker.

The classification of the circuit breaker:-

On the bases of medium of are extinction as follows:-

a) Air break circuit-breaker ( miniature circuit- breaker)b) Oil circuit breaker ( tank type or bulk oil).c) Minimum oil circuit breaker.d) Air blast circuit breaker.e) Sulpher hexafluoride circuit breaker( single pressure or double pressure)f) Vacuum circuit breaker

Each leading manufactures of circuits breakers develops two or more types of the circuit breakers for every voltage class. The construction of the circuit breaker depends upon its type (are quenching medium) voltage ratting and structured from.

Air –break circuit breaker:-

Utilize air at atmospheric pressure for are extinction.

Air blast-circuit breakers:-

Utilize high pressure compressed air for extinction. They need compressed air plant.

Bulk oil and minimum oil circuit breaker:-

Utilized dielectric oil ( transformer oil) for are extinction, in bulk oil circuit breakers, the contents is are separated inside a steel tank filled with dielectric oil. In minimum oil circuit brake the contacts are separated in an insulating housing (interrupter filled with dielectric oil).

SF6 CIRCUITS BREAKERS:-

Sulphur hexa-fluoride gas is used for are extinction three are two types:-

Single pressure puffer type SF6 circuit breaker:- in which the entire circuit breaker is filled with SF6 gat at signal pressure (4 to 6kg/sq.cm). the pressure and gas flow required for are extinction is obtained by piston Action.

Double pressure type SF6 circuit breaker:- in which the gas from high pressure system is released into low pressure system over they are during the arc quenching process.

In vacuum circuits- breakers the fixed and moving contactors are housed inside a permanently seated vacuum interrupter. They are is quenched as the contacts are sepreetc in high vacuum.

Batteries:-

Introduction:- all generating plant and substation, need DC supply for protection and control purpose the DC supply is obtained from storage battery. i.e. 110v, 220v. battery capacity is the useful quantity of electricity that can be drawn form the battery at a specific rate of discharge before it final voltage of 1.75v is reached. It is expected in AH.

DC . BATTERY;-

Dc battery are used in power house for the protection system i.e. all protective relays ,alarm and trip of ABCB and other type of breakers. Indication of various insulation of controls.

Station battery:-

DC supply used for the trip circuit and the control circuit indication and alarm in the power station.

Tow types of charging the battery:-

1) Boost charging.2) Float charging.

Used in generating station and substation DC auxiliary power sources is required for the protection system. To operate protective relay and for the control system DC battery is required . this supply is usually 30v, 110v, 220v. as per availability of control system. The batteries are placed in well ventilated battery cell are placed in wooden racks. Total capacity all battery is 220v.

For alarm and indication ; 50v is used (it is step down from 220v DC). For 33kv, switch yard protection;- 30v is used (it step down from220v DC)

For control system:-220v.

Here in bassi power house the total cells=110 and each having capacity of 2 volt each

750AH bank capacity.

Battery charging:-

Batteries have to be charged occasionally to restore them the working condition ,during charging direct is passed through the battery in a direction opposite in a direction opposite to that within the battery is being used. The charging current usually obtained from a charger which is a selenium or germanium or silicon rectifier fed from AC mains through a transformer designed to step the voltage up or down to a suitable valve, the positive an negative is connected to the positive terminal respectably. At the commencement of the charge the voltage around 2.2 volt cell. As the charge proceeds the required voltage increase the reaches 2.6 volts per cell at the end of charge. The channel must be capable of supplying g this voltage.

Initial charge:-

New batteries are received in uncharged condition and have to be charged before they can be saved. The initial charging consists in passing a current into the battery for a number of hours as recommended by the manufacturing the ability of a battery to deliver its rated capacity and give a satisfactory performance depends to a large extent to initial charges. As such the instruction of the manufactures regarding initial charging must be closely followed.

Trickle charging :

The station batteries used to power stations and sub- stations are permanently connected to load in parallel with the charger. The batteries are continuously charged at a slow rate to compensate the discharge due to the load or the battery and the self discharge. Small intermittent discharge are also taken care of by trickle charging. The battery also remain in a fully charged condition. If the cells gas appreciable and the voltage exceeds 2.35 volt per cell. The trickle charge rate should be reduced slightly . the charge in the trickle charge rate should be very minute and the effect observed over a period of several months. After any temporary heavy discharge the battery should be put on “ Trickle charge”.