origonal larji report.docx

8/14/2019 origonal larji report.docx

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LARJI HYDROPOWER PROJECT (3*42MW)

SUBMITTED BY

GAURAV& NISHANT VERMA

DEPARTMENT OF MECHANICALENGINEERING

JUNE, 2013


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LARJI HYDROPOWER PROJECT (3*42MW)

A Industrial seminar report submitted

in partial fulfillment of the requirements

for the award of the degree of

BACHELOUR OF TECHNOLOGY

in

(MECHANICAL ENGINEERING)

by

(Roll No.46015& 46033)

DEPARTMENT OF MECHANICALENGINEERING

JUNE, 2013


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CONTENT

Sr. No. Particulars Pg. No.

1Certificate 4

2 Acknowledgement 5

3 Detail of contents 6-8

4 Chapter 1: Introduction about Hydro Plant 9-17

5 Chapter 2: Plant Location 18-29

6 Chapter 3: Specification of Equipment of hydro Plant 30-44

7 Chapter 4: Operation and Maintenance 44-52

8 Chapter 5: Conclusion 53


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Certificate


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ACKNOWLEDGEMENT

I do express my deepest sense of gratitude and indebtedness towards my training

supervisor J.E. AshishDepartment of HPSEBLarji, thalot, distt. Mandi (H.P.), for their

invaluable guidance, constant encouragement, suggestions, great patience, and continuous

technical support which helped me, survive through crests and troughs of my dissertation work

which got completed successfully. It is a great privilege to work under them, who motivated me

in every course of my work and made me believe in myself.

I also thank Mr. Sunil kumar HOD ME and co-ordinator who have equally given me valuable

guidance and advise to improve quality of my work. I express my sincere thanks for their

suggestions, constant and continuous support throughout this work. I would like to extend my

sincere thanks to my colleagues for their

valuable assistance and co-operation.

I would like to express my heartfelt appreciation for my parents and family members

for their constant encouragement and blessings.

I save the best for my God who destined me to go beyond deliverance into eternal land

of true joyfulness to experience the fullness of his purpose and plan in my life. I thank you God

for all things happened and will be happening to my life; Youre gracious, Your ultimate

sacrifice made my life possible. I will never be tried of thanking You!

NISHANT VERMA

Date:

Place:

ROLL NO 46033


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CONTENTS

CHAPTER 1

1.1 Introduction1.2 Historical background of the project Civil work Electro mechanical work Transmission line Commissioning of the project

1.3 Hydro power plan Hydro electricity Hydro power is produced Cost of hydro electricity

1.4 Generating methods Conventional dam Pumped storage Run of the river Tide

1.5 Type of plant1.6 Water turbines Type of turbine with typical range of heads

1.7 Advantages and disadvantages Advantages Disadvantages

CHAPTER 2

2.1 Hydro generator

Stator Rotor Bearing Description of turbine equipment

Spiral casing Draft tube cone Draft tube kneeling Stay ring Lower ring Runner Turbine shaft Set of guide vanes


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Turbine top cover. Regulating ring Guide earthing Oil pumping unit Pressure accumulator Oil leakage unit Cooling water system Dewatering and drainage system. Main inlet valve Governor Power transformer Power equation

CHAPTER 3

3.1 Hydro generator

Specification3.2 Turbine.

Specification3.3 Main inlet valve.

Specification.3.4 Generator transformer

Specification Function.

3.5 Unit auxiliary transformer

Specification Function.

3.6 Unit excitation transformer

Specification. Function

3.7 Station transformer

Specification. Function.


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3.8 Battery bank

Specification. Type of cell

3.9 Battery charger

48V DC PLCC Battery charger 1,2 220V DC Distribution board 1,2

3.10 Gas insulated substation type F35

Performance Characteristics Customer benefits Technical data Main components Function of GIS

CHAPTER 4

Operation and Maintenance

4.1 Best practice in operation & maintenance of hydro plant

4.2 Maintenance practice

Turbine & its auxiliary

Turbine Governor Governor & its auxiliary Transformer & switchyard. Emergency D.G. set Other P.H. equipment

CHAPTER 5

Conclusion

LIST OF FIGURES:-

Figure 1.1- Inside Larji Power House Figure 2.1- internal view of generator Figure 2.2- internal view of turbine Figure 4.1- water conduction system


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CHAPTER 1

1.1 INTRODUCTION:-

INDIA is endowed with economically exploitable and viable hydro potential assessed to be

about 84,000 MW at 60% load factor (1,48,701 MW installed capacity). In addition, 6780 MW

in terms of installed capacity from Small, Mini, and Micro Hydel schemes have been assessed. In

addition, 56 sites for pumped storage schemes with an aggregate installed capacity of 94,000

MW have been identified. However, only 19.9% of the potential has been harnessed so far.

Figure 1.1: Inside Larji Power House


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1.2 BACKGROUND:-

1.2.1 The Himachal Pradesh State Electricity Board Limited (hereinafter referred to as HPSEB

Ltd) is a deemed licensee under the first proviso to section 14 of the Act for distributionand supply of electricity in the State of Himachal Pradesh as well as a generation

company falling within the definition of section 2 (28) of the Electricity Act, 2003

(hereinafter referred to as the Act).

1.2.2 The HPSEB Ltd has filed Petition No. 171 of 2010 on August 23, 2010 before theHimachal Pradesh Electricity Regulatory Commission (hereinafter referred to as the

Commission) for determination of Capital Cost of Larji Hydro Electric Project (the

Project) and determination of generation tariff from FY 2007-08 to FY 2010-11 undersections 62 and 64 of the Electricity Act, 2003, read with the Himachal Pradesh

Electricity Regulatory Commission (Terms and Conditions for Determination of Hydro

Generation Tariff) Regulations, 2007, framed by the Commission, which now stands

repealed by the HPERC(Terms and Conditions for Determination of Hydro GenerationTariff) Regulation, 2011 with the stipulation that the provisions concerning the tariff for

the Control Period ending on the 31st

March, 2011 and the provision for conduct ofproceedings for its revocations, variation or alternation, as stood before such repeal, shallcontinue to be in-force.

1.2.3 This Order relates to the above mentioned Petition under the Multi Year Tariff regime.Further, this Order also relates to truing up of ARRs for the period from FY 2007-08 to

FY 2010-11 against the ARRs and tariff provisionally approved by the Commission forelectricity generated from Larji HEP (126 MW) in its Multi Year Tariff Order for FY

2008-09 to FY 2010-11, dated May 30, 2008.

1.3 FUNCTION OF THE COMMISION:-

1.3.1 The Himachal Pradesh Electricity Regulatory Commission was established and

incorporated by the Government of Himachal Pradesh through a notification dated

December 30, 2000, under section 17 of the repealed Electricity Regulatory CommissionsAct, 1998 (14 of 1998), and now covered under the first proviso to section 82 of the

Electricity Act, 2003, with its headquarters located at Shimla.

1.2.4 The Act guides the Commissions approach to regulation. The Act mandates theCommission to take measures conducive to the development and management of the

electricity industry in an efficient, economic and competitive manner.

1.2.5 The Commission derives its powers under section 86 of the Act, which came into forcewith effect from June 10, 2003. The Act repealed the Indian Electricity Act, 1910, the

Electricity (Supply) Act, 1948 and the Electricity Regulatory Commissions Act, 1998.

1.2.6 As part of the tariff related provisions of the Act, the State Electricity RegulatoryCommission (SERC) has to be guided by the Act, the National Electricity Policy (NEP)

and the National Tariff Policy (NTP).


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1.2.7 The functions assigned to the Commission under the Act are as follows:- The State Commission shall discharge the following functions, namely: -

determine the tariff for generation, supply, transmission and wheeling of electricity,wholesale, bulk or retail, as the case may be, within the State:

Provided that where open access has been permitted to a category of consumersunder section 42 of the Act, the State Commission shall determine only the wheeling

charges and surcharge thereon, if any, for the said category of consumers;

regulate electricity purchase and procurement process of distribution licenseesincluding the price at which electricity shall be procured from the generating

companies or licensees or from other sources through agreements for purchase of

power for distribution and supply within the State;

facilitate intra-State transmission and wheeling of electricity; issue licences to persons seeking to act as transmission licensees, distributionlicensees and electricity traders with respect to their operations within the State; promote cogeneration and generation of electricity from renewable sources of energy

by providing suitable measures for connectivity with the grid and sale of electricityto any person, and also specify, for purchase of electricity from such sources, a

percentage of the total consumption of electricity in the area of a distribution

licensee;

adjudicate upon the disputes between the licensees and generating companies and torefer any dispute for arbitration;

levy fee for the purposes of this Act; specify State Grid Code consistent with the Grid Code specified under clause (h) of

sub-section (1) of section 79;

specify or enforce standards with respect to quality, continuity and reliability ofservice by licensees;

fix the trading margin in the intra-State trading of electricity, if considered,necessary;

discharge such other functions as may be assigned to it under this Act. The State Commission shall advise the State Government on all or any of the following

matters, namely: -

promotion of competition, efficiency and economy in activities of the electricity industry; promotion of investment in electricity industry;


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reorganisation and restructuring of electricity industry in the State; matters concerning generation, transmission, distribution and trading of electricity or any

other matter referred to the State Commission by that Government.

1.4 HISTORICAL BACKGROUND OF THE PROJECT:-

1.4.1 Larji HEP with an installed capacity of 126 MW (3 Units each of 42 MW), a run- of-riverscheme on river Beas with pondage, with underground power station and staticexcitation, situated in District Kullu, was initially taken up for construction in 1987 after

its techno-economic approval was received from Government of India (GOI) on August

04, 1986 and the approval from Planning Commission was received on March 30, 1987 at

a total cost of Rs.168.85 crore. The total cost of Rs.168.85 crore included civil worksconsisting of Rs.99.95 crore Electrical works of Rs.54.40 crore and cost of transmission

line of Rs.18.50 crore. In the DPR prepared in 1987, following structures were envisaged

for the project:-

Diversion Tunnel on left bank 30.30 m high concrete Gravity Dam Desanding arrangements with 4 chambers. 4850 m long, 8.50 m dia circular Power Tunnel. Two open ended Surge Shafts each of 44m height 28m dia. Surface Power House with 3 Units each of 42 MW Rectangular, 29 m long Tail Race channel.

1.4.2 However, despite techno-economic clearance by the Central Electricity Authority (CEA)on August 4, 1986 and approved by Planning Commission G.O.I. on March 30, 1987 for

an estimated cost of Rs.168.85 crore, the construction of the Larji HEP did not proceed as

planned, primarily due to paucity of funds. From 1987 to March, 1999 only limitedinfrastructure was developed and detailed investigations were carried out. Initially, the

State Government decided to take up the project for execution in 1991. Consequent to

findings of Sub-surface geological explorations which were concurrently in progress,some inherent changes in Project components were found necessary by the erstwhile

HPSEB (the Board) in consultation with the Panel of Experts (P.O.E), which was

constituted by the Board in 1995 for suggesting and firming up the necessary changes inthe DPR. As practically no work had been carried out in respect of main structures

envisaged in 1987 proposal, the Board decided to incorporate following changes in main

project structures:-

Concrete Dam was replaced by a gated diversion barrage. 6 Nos. radial gates in spillway were replaced with 5 Nos. radial gates in the

diversion barrage but of bigger size.

Desanding arrangements of 4 chambers was retained with bigger sizes. HRT length was reduced to 4119.86 m retaining old dia and type of Power Tunnel.


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Adit locations were changed which changed their length type of Power Tunnel. Two numbers Surge Shafts were replaced by one open Surge Shaft after making

changes in height and size.

Surface Power House was replaced by underground Power House 29 m long Tail Race channel was replaced by 258mx10m dia Tail Race Tunnel. A new provision of TRT chamber was made.

1.4.3 The State Government decided to take up the Project for active construction in 1998.Accordingly, a revised DPR (March 1999) with the above mentioned changes in scope ofthe Project was submitted to the Central Electricity Authority (CEA) for according

Techno Economic Clearance (TEC) and Planning Commissions Approval. The Central

Electricity Authority (CEA) accorded Techno Economic Clearance on January 14, 2000

at revised cost estimate ofRs.796.98 crore including transmission line and IDC. This

included civil works costing Rs.419.03 crore. Electro mechanical works of Rs.221.05crore, cost of transmission lines as Rs.25.75 crore and estimated IDC at Rs.131.16 crore

with an overall per MW cost of Rs.6.32 crore.

1.4.4 Civil works: Except for HRT works (Package II) for which letter of intent had beenissued in April, 1999, all other Civil/ Mechanical Works for the project were awarded

during April, 2000 to January, 2002.

1.4.5 Electro Mechanical works:the HPSEB Ltd entered into two main contracts for ElectroMechanical works for the Project. The first contract was for Ex-manufacturingworks/place for main equipment with Alstom make SF6 GIS and mandatory spares and

the second contract was for main Equipment and mandatory spares, unloading andhandling at site, storage, installation, testing and commissioning including performancetesting and insurance covering all activities, which was awarded to M/S BHEL on

February 15, 2001.

1.4.6 Transmission line: The construction of transmission lines was decided to be taken upinternally by the Board. There were two 132 kV D/C lines, one from Larji to Gaggalwhich was completed in May, 1993 and commissioned in December, 1998. However, the

line was charged on 33 kV for supplying additional power to Kullu Valley. The second

line from Larji to Kangoo was completed in June, 2006.

1.4.7 Commissioning of the Project: The First Unit (Unit-III) of Larji HEP wascommissioned in September, 2006, Second Unit (Unit-II) was commissioned in October,2006 and Third Unit (Unit-I) was commissioned in February, 2007.

1.5 HYDRO POWER PLANT:-

1.5.1 Hydroelectricityis the term referring toelectricity generated byhydropower; theproduction of electrical power through the use of the gravitational force of falling or
http://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Electricity


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flowing water. It is the most widely used form ofrenewable energy,accounting for 16

percent of global electricity consumption, and 3,427 terawatt-hours of electricity

production in 2010, which continues the rapid rate of increase experienced between 2003

and 2009.

1.5.2 Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32percent of global hydropower in 2010. China is the largest hydroelectricity producer, with

721 terawatt-hours of production in 2010, representing around 17 percent of domestic

electricity use. There are now three hydroelectricity plants larger than 10 GW: theThree

Gorges Dam in China,Itaipu Dam in Brazil, andGuri Dam in Venezuela.

1.5.3 The cost of hydroelectricity is relatively low, making it a competitive source ofrenewable electricity. The average cost of electricity from a hydro plant larger than 10

megawatts is 3 to 5 U.S. cents per kilowatt-hour.[1]

Hydro is also a flexible source of

electricity since plants can be ramped up and down very quickly to adapt to changing

energy demands. However, damming interrupts the flow of rivers and can harm local

ecosystems, and building large dams and reservoirs often involves displacing people and

wildlife. Once a hydroelectric complex is constructed, the project produces no direct

waste, and has a considerably lower output level of thegreenhouse gascarbondioxide (CO2) thanfossil fuelpowered energy plants.

1.6 GENERATING METHODS:-

1.6.1 CONVENTIONAL DAM:-

Most hydroelectric power comes from thepotential energy ofdammed water driving

awater turbine andgenerator.The power extracted from the water depends on the volume

and on the difference in height between the source and the water's outflow. This height

difference is called thehead.The amount ofpotential energy in water is proportional to the

head. A large pipe (the "penstock") delivers water to the turbine.

1.6.2 PUMPED STORAGE:-

This method produces electricity to supply high peak demands by moving water

betweenreservoirs at different elevations. At times of low electrical demand, excess

generation capacity is used to pump water into the higher reservoir. When there is higher

demand, water is released back into the lower reservoir through a turbine. Pumped-storage

schemes currently provide the most commercially important means of large-scalegrid

energy storage and improve the daily capacity factor of the generation system.

1.6.3 RUN-OF-THE-RIVER:-

Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that

the water coming from upstream must be used for generation at that moment, or must be

allowed to bypass the dam.

1.6.4 TIDE:-

Atidal powerplant makes use of the daily rise and fall of ocean water due to tides; such

sources are highly predictable, and if conditions permit construction of reservoirs, can also
http://en.wikipedia.org/wiki/Renewable_energyhttp://en.wikipedia.org/wiki/Three_Gorges_Damhttp://en.wikipedia.org/wiki/Three_Gorges_Damhttp://en.wikipedia.org/wiki/Itaipu_Damhttp://en.wikipedia.org/wiki/Guri_Damhttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-wi2012-0http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-wi2012-0http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-wi2012-0http://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Potential_energyhttp://en.wikipedia.org/wiki/Damhttp://en.wikipedia.org/wiki/Water_turbinehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Head_(hydraulic)http://en.wikipedia.org/wiki/Potential_energyhttp://en.wikipedia.org/wiki/Penstockhttp://en.wikipedia.org/wiki/Reservoir_(water)http://en.wikipedia.org/wiki/Grid_energy_storagehttp://en.wikipedia.org/wiki/Grid_energy_storagehttp://en.wikipedia.org/wiki/Capacity_factorhttp://en.wikipedia.org/wiki/Tidal_powerhttp://en.wikipedia.org/wiki/Tidal_powerhttp://en.wikipedia.org/wiki/Capacity_factorhttp://en.wikipedia.org/wiki/Grid_energy_storagehttp://en.wikipedia.org/wiki/Grid_energy_storagehttp://en.wikipedia.org/wiki/Reservoir_(water)http://en.wikipedia.org/wiki/Penstockhttp://en.wikipedia.org/wiki/Potential_energyhttp://en.wikipedia.org/wiki/Head_(hydraulic)http://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Water_turbinehttp://en.wikipedia.org/wiki/Damhttp://en.wikipedia.org/wiki/Potential_energyhttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Greenhouse_gashttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-wi2012-0http://en.wikipedia.org/wiki/Guri_Damhttp://en.wikipedia.org/wiki/Itaipu_Damhttp://en.wikipedia.org/wiki/Three_Gorges_Damhttp://en.wikipedia.org/wiki/Three_Gorges_Damhttp://en.wikipedia.org/wiki/Renewable_energy


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bedispatchable to generate power during high demand periods. Less common types of

hydro schemes use water's kinetic energy or undammed sources such as

undershotwaterwheels.

1.7 TYPES OF PLANT:-

1.7.1 SMALL TYPE:- Small hydro is the development ofhydroelectric power on a scale serving a small

community or industrial plant. The definition of a small hydro project varies but a

generating capacity of up to 10megawatts (MW) is generally accepted as the upper limit

of what can be termed small hydro. This may be stretched to 25 MW and 30 MW

inCanada and theUnited States. Small-scale hydroelectricity production grew by 28%

during 2008 from 2005, raising the total world small-hydro capacity to 85GW. Over

70% of this was inChina (65 GW), followed byJapan (3.5 GW), theUnited States (3

GW), andIndia (2 GW).

Small hydro plants may be connected to conventional electrical distribution networks as asource of low-cost renewable energy. Alternatively, small hydro projects may be built inisolated areas that would be uneconomic to serve from a network, or in areas where there

is no national electrical distribution network. Since small hydro projects usually have

minimal reservoirs and civil construction work, they are seen as having a relatively low

environmental impact compared to large hydro. This decreased environmental impact

depends strongly on the balance between stream flow and power production.

1.7.2 MICRO:-

Micro hydro is a term used forhydroelectric power installations that typically produce up

to 100KW of power. These installations can provide power to an isolated home or small

community, or are sometimes connected to electric power networks. There are many of

these installations around the world, particularly in developing nations as they can provide

an economical source of energy without purchase of fuel.[12]

Micro hydro systems

complementphotovoltaic solar energy systems because in many areas, water flow, and thus

available hydro power, is highest in the winter when solar energy is at a minimum.

1.7.3 PICO:-

Pico hydro is a term used forhydroelectric power generation of under 5KW.It is useful in

small, remote communities that require only a small amount of electricity. For example, to

power one or two fluorescent light bulbs and a TV or radio for a few homes.[13]

Even

smaller turbines of 200-300W may power a single home in a developing country with a

drop of only 1 m (3 ft). Pico-hydro setups typically are run-of-the-river,meaning that damsare not used, but rather pipes divert some of the flow, drop this down a gradient, and

through the turbine before returning it to the stream.
http://en.wikipedia.org/wiki/Dispatchable_generationhttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Water_wheelhttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Megawatthttp://en.wikipedia.org/wiki/Canadahttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Gigawatthttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Japanhttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Kilowatthttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-11http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-11http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-11http://en.wikipedia.org/wiki/Photovoltaicshttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Kilowatthttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-12http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-12http://en.wikipedia.org/wiki/Hydroelectricity#cite_note-12http://en.wikipedia.org/wiki/Hydroelectricity#Run-of-the-riverhttp://en.wikipedia.org/wiki/Hydroelectricity#Run-of-the-riverhttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-12http://en.wikipedia.org/wiki/Kilowatthttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Photovoltaicshttp://en.wikipedia.org/wiki/Hydroelectricity#cite_note-11http://en.wikipedia.org/wiki/Kilowatthttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Japanhttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Gigawatthttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Canadahttp://en.wikipedia.org/wiki/Megawatthttp://en.wikipedia.org/wiki/Hydroelectric_powerhttp://en.wikipedia.org/wiki/Water_wheelhttp://en.wikipedia.org/wiki/Kinetic_energyhttp://en.wikipedia.org/wiki/Dispatchable_generation


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1.8 WATER TURBINES:-

Waterturbines were developed in the 19th century and were widely used for industrial

power prior toelectrical grids. Now they are mostly used forelectric power generation.

They harness a clean andrenewable energy source, but can cause indirect environmental

damage associated with water storage and construction.

1.8.1 TYPES OF TURBINES WITH TYPICAL RANGE OF HEADS:-

Hydraulic wheel turbine0.2


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Being located in remote regions leads to development of interior backward areas(education, medical, road communication, telecommunication etc.)

1.9.2 DISADVANTAGES:-

Away from Load Centers, Evacuation of power is Big Problem. Environmental /Ecological & rehabilitation/ Resettlement Problem due to submergence/

Construction activities

Difficulty in Investigation / Implementation due to Remoteness of the area Long gestation period Lack of availability of long term finance Geological surprises resulting in the time and Cost Over-runs. Hydro Projects suffer from production Risks since the project is planned based on the

Historical data, which may not occur in future.


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CHAPTER2

2.1 HYDRO GENERATOR

The hydro generator at larji HEP is a vertically placed generator. The major

mechanical parts of the generator are stator, rotor, shaft and turbine. Since the rotor and stator are

enclosed, these are not visible. Main content are explained as follow.

2.1.1 STATOR :-

STATOR FRAME:-It is made of wieldable steel plates and has adequate depth to prevent distortionduring any operation. Joints between the segments are heavily flanged internally and

coupled by number of studs. Water cooled air cooler are fixed on the opening ,provided on outer casing of the stator frame.

STATOR CORE:-It is build up of stampings of high ratings, hot rolled silicon alloy steel with varnish

insulation on both sides. Stator core is pressed between steel plate ends through nonmagnetic radial fingers welded on them. The core is securely clamped by number of

long studs along the outer periphery of the core, extending over its full height.

STATOR WINDING:-It is a double layer, bar type wave wound. brazing joins the bar ends and each joints

is tested by ultrasonic wave for perfection. the stator winding is star connected. three

main and three neutral terminals have been brought out side the stator frame. in order

to prevent condensation of winding during period of shut down, low temperaturesheaters are mounted below the lower air baffles.

2.1.2 ROTOR:-

ROTOR:-The rotor has been design to safety with stand all mechanical stresses imposed by themaximum run way speed. The dynamic balancing of the rotor shall be carried out to keep

values of rotor vibration within allowable limits.


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FIGURE 2.1 Internal view of generator

ROTOR RIMS:-

the rotor rim is built up from sheet steel laminations each covering two pole pitches andsuccessive layers of laminations overlapped to give adequate strength to the rim. T

shaped slots in the outer periphery of the ring receive similar shape projection on the pole.

The rim is secured tangentially to the rectangular bars of the spider with sets of five partskeys having a master key in the middle and a set of taper keys on the each side so as to

allow the rim to float freely during operation.


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SHAFT AND THRUST CUM GUIDE BEARING COLLAR:-It is made from high quality alloy steel. It has been accurately mechanism and has a holebored through the centre for inspection and other purpose. The bottom surface of collar is

polished in fine limits to act as runner surface.

POLES WITH FIELD WINDING:-poles are of laminated construction consisting of sheet steel poles punching, clampedbetween heavy steel and plates by means of studs. The poles core has a number of T

shaped tails to engage with corresponding T shaped tails in the rotor rim. The damper

windings bar are of circular copper section and are embedded in poles face. The ends of

damper bar are short circuit together by copper segments. The field windings are made ofspecial profile copper strip wound on edge. The coils are electrically heated and

pressurized to heal the turn insulation and thus strengthen the coil.

SLIP RINGS AND BRUSH GEAR:-slip rings are of mills steel and shall be mounted on extension shaft. The brush gear

collector shall be mounted on insulated studs supported on the upper brackets and is

conveniently accessible for maintenance and inspection. The insulation for slip rings andtheir connection is non hygroscopic and oil resistant. Slip rings shall have condition for

reversing their polarity without removing the field poles or its collector rings by

interchanging connection of the field leads at brush gear.

2.1.3 BEARINGS:-

THRUST BEARING:-It is of pivoted segmented type, in which stationary parts consists of sets of pivoted

segmented pads supported on circular pad supports. Bearing shall be self lubricated typewith plug in type oil coolers located in oil reservoir. Each pad rests on pad supports

which work like spring plates and provided cushioning effect to whole assembly. Radial

movements are prevented by the mean of stoppers.Thrust bearing collar is accuratelyperpendicular to the axis of the shaft. Thrust bearing pads are completely immersed in

the oil and would be cooled by mean of oil cooler units. Oil used in the trust bearing is of

46 no. of the prime oil. The edge pads are tapered to allow the oil to enter in the gapsbetween pads and runner. Pads are designed so that tilting is possible, thus enabling theautomatic adjustment of required lubrication gap for actual speed and load.

GUIDE BEARINGS:-the guide bearing is of pivoted pad type consisting of a raw of white metal pads arrangedin a support ring. A pivoted bar is bolted to the back of each guide pad to enable the pad

to move up and down slightly to take up stable position and facilitates formation of the


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oil film while running. Guide bearing pads are immersed in oil of 68 prime oil.

Resistance and dial thermometer are provided in pads, and oil bath for temperature

measurement and protection against over heating.

UPPER BRACKET:-The upper bracket supports the weight of the stationary parts of brush gear. Upper geargenerator cover and mechanical over speed devices etc. It is to be placed on the statorframe.

LOWER BRACKET:-The lower bracket houses is the lower guide bearing. The bracket is designed to carry the

weight of the rotating parts of the generator and turbine as well as hydraulic thrust. It is

designed in such a way that it is possible to lift it through the stator core.

BREAKING AND JACKETING SYSTEM:-To apply the brakes, air at 4.0-5.0 atmospheric pressure shall be fed in to the cylinder

from the station compressed air system. Brakes shall be automatically applied, when thespeed of the rotor reduced to a present value and shall remain applied continuously, so

that the unit stop completely. However, it shall be possible to apply the brakes manually.

The brakes shall automatically reset after complete stopping of the generator. Limitswitches have been provided for each brake to prevent the machine from starting, if any

brake be in the raised position and provide ON and OFF indication on the unit control

room.

CARBON DUST COLLECTION EQUIPMENT:-Carbon dust is produced due to continuous rubbing of carbon brushes on slip rings. To

prevent deposition of this dust on slip ring, a chamber has been provided to enclosed the

slip rings area and the air from this chamber is extracted by an exhaust fan through asheet metal duet.

BRAKE DUST COLLECTION EQUIPMENT:-The brake dust collection equipment consists of an extraction unit, hoppers around brakeassembly for trapping the brake dust and flexible hoses for connecting hoppers toextraction unit. Provision has been made in the control schematic to the unit for its

ON/OFF operating in auto mode.

VENTILATION:-The generator has closed circuit type ventilation. Twelve air cooler units have been

installed in the outer periphery of the stator frame and the cooled air is discharged into


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the space surrounding the stator. Part of this air is then returned to fan below rotor

through ducts in the foundation and remainder cooled air returns to the fan above rotor.

FANS:-fans of suitable design are fixed at each end of the rotor rim at top and bottom. Suitable

air guides have been provided to ensure proper distribution of air in the machine.

AIR COOLERS:-A number of the air cooler are fixed on the stator frame for dissipating the heat in theform of losses in the generator. Each air cooler consists of a rectangular nest of tube

between two water chambers, arranged for the air to flow over water through the tubes.

The tubes are of cuprous nickel alloy and have coiled coil tinned copper wire around its

periphery to increase cooling surface.

2.1.4 DESCRIPTION OF TURBINE EQUIPMENTS:-

FIGURE 2.2 Internalview of turbine


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SPIRAL CASING:-It is logarithmic form and substantially circular in the cross-section, designed to

withstand maximum water hammer pressure. The diameter at the inlet is 4200 mm. It ismade from boiler steel plates in minimum number of section of different thickness and

shall be welded to straying at site.

DRAFT TUBE CONE:-It is fabricated from plates and made in three parts to facilitate runner removal from

bottom at valve floor. The upper draft tube cone is fabricated from stainless steel plates.

On the upper side it is connected to bottom flange of the lower ring of the guideapparatus and on the lower side it is bolted to the intermediate draft tube cone. The

intermediate draft cone is fabricated from structural steel and on the upper side it is

connected to the upper cone and end is kept in position with the help of the lower draft

tube cone. The lower draft cone is also fabricated from carbon steel plates and fixed tothe top ring of draft tube knee lining. To prevent leakage of water, all the joints have

been provided with rubber sealing cords.

DRAFT TUBE KNEE LINING:-It is fabricated from steel plates and is ribbed on its outer surface to give rigidity. It isalso manufactured in number of parts. A drainage box has been provided at the side of

the liner for dewatering turbine water path into dewatering gallery through a pipe and

gate valve.

STAY RING:-It is designed to withstand the hydraulic forces and is of cast fabricated construction. It

consists of cast upper and lower belts connected together by steam lined cast steel stay

vanes for drainage the top cover leakage water by gravity. This is designed to givehydraulic losses, to conform to the flow formed by spiral casting, to guide the water to

vanes and meeting the strength requirements.

LOWER RING:-The lower ring of guide apparatus (bottom ring) is fabricated from steel plates. The

cups, which house the lower brushes of guide vanes are rigidly to the lower ring so that

they can be taken out and replaced without dismantling either lower ring or turbine topcover. The lower ring is fixed to stay ring.

RUNNER:-The runner shall be Francis type having inlet diameter of 3450 mm. It is made from

stainless steel. The runner cone is also of stainless steel. The design is such that thevelocity of the water at the skirt is relatively low to minimize silt erosion. All the surface

of the runner is ground smooth and is free from hollow, cracks or projections.


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TURBINE SHAFT:-The turbine shaft of external diameter 750 mm and internal diameter 400 mm is forged

from high quality manganese steel. The shaft has flanges at both its ends. The upperflanged of the turbine shaft is connected to the flanged of the generator shaft and its

lower flange, the turbine shaft is connected with the runner. The connection at both the

ends is made with the help of fitted bolts. The axial load as well as the torque istransmitted through these bolts. The shaft is provided with a bearing skirt for guide

bearing and stainless steel rotating sleeve for turbine sealing.

SET OF GUIDE VANES:-The guide vanes, 24 in number are made of cast stainless steel and have a smooth

hydraulic profile. The guide vanes are housed between the turbine top cover and lower

ring. The turning of the guide of the guide vane is carried by two servomotors. Safety

share pins set shared off, in the event of a foreign body getting wedged between thevanes, thus protecting the guide vanes and turning mechanism against any damage.

Contacts have been provided for signalling in case of shear pin failure. The limitswitches are provided to give the alarm signal when any of the shear pin gets broken due

to jamming of guide vanes. The limit switches are oil/water tight and special glands areused to prevent entry of water in the limit switches through the cables. Stoppers are

provided to prevent movement of guide vanes beyond the fully opened and closed

position.

TURBINE TOP COVER:-The turbine top cover is fabricated from steel plates and is made in two parts. It is rigidly

connected to the upper belt of stay ring. provision for gravity drainage of top cover has

been made. In its internal vertical cylinder, windows have been provided to have accessto turbine sealing for repairs. Renewable stainless steel upper stationary labyrinth

sealing has been fixed with top cover.

REGULATING RING:-The regulating ring is made of welded construction. It is supported and guided on the

support for regulating ring. Which is also fabricated on the turbine top cover. The

regulating ring is provided with bronze pads on the surfaces, rubbing against the support

and these pads are immerged in an oil bath to minimize friction. Oil is poured in the baththrough a special funnel provided for the purpose. The regulating ring is connected with

servomotors.

GUIDE BEARING:-Oil lubricating turbine guide bearing of segment type has been adopted in the design. Itconsists of eight Babbitt line segment arranged along the outer circumference of bearing

belt of the shaft. The bearing body is made of mild steel plates and is fixed to the top

turbine top cover with the help of studs. The guide bearing oil cooler are located inside


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guide bearing. under stationary condition, the Babbitt line segments are kept immerged

in the oil bath. Radial holes have been provided in the skirt of the shaft to act as a

centrifugal pumps, when the shaft rotates, thus forcing the oil under pressure to passthrough the gap between the segment and shaft and take a wedge form and a oil film is

formed ensuring lubrication of guide bearing. The oil flow over the cylinder to guide

bearing oil cooler.The oil, after passing through the cooler, flow to the inner tank. Thus

the complete circulation of oil is achieved. Cooling water is fed to the oil cooler at apressure of 3 to 4 kg/cm2. Level relay and flow relay with the alarm are providing for

indicating low oil level and less flow of cooling water respectively. For temperature

control thermo signalizes and resistance thermometers are provided in the bearingsegments as well as in oil bath.

OIL PUMPING UNIT:-Each unit is provided with its own pressure system. The pumping unit is equipment with

two screw pumps driven by electric motors through flexible coupling and of sufficientcapacity, to meet all the oil requirement of turbine. The pump with the turbine is

mounted on the top of oil sump tank. Pumping of the oil is mainly carried out by themain pump under the control of idler cum safety valve to maintain the pressure in thepressure accumulator. When the oil pressure drops to a present value in the pressure

accumulator, the pressure switch aculates the standby pump to start. When the pressure

build up again, the pressure switch operates to stop the pump.

PRESSURE ACCUMULATOR:-It is a fabricated pressure vessel. It is an oil accumulator filled with oil and compressed

air, and serves as the source of energy for driving the power organs of the system by

means of oil under pressure.

OIL LEAKAGE UNIT:-the oil leakage unit is intended for the collection of oil leakage from the servomotor of

guide apparatus and periodic pumping from the tank of leakage unit into the sump tank

of oil pressure unit. The O.L.U. consists of tank and mounted on its pump motor set.

COOLING WATER SYSTEM:-water shall be taken from the individual penstock of each unit through self cleaning strainer

and cyclonic and will be supplied to serve the following requirement of respective unit:-

Cooling water for generating air cooler. Cooling water for heat exchanger of generator guide and thrust bearing. Cooling water for turbine sealing, turbine guide bearing etc. Cooling water for transformer,


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Cooling water for supply to compressor.The water after passing through the self cleaning strainer and cyclonic strainer will

be feed to the various equipments. Water from the various equipments will bedirectly discharged into the tailrace.

DEWATERING AND DRAINAGE SYSTEM:-this is common for all units the water of draft tube is collected in sump. The bottom of

sump is at an elevation of 880m. Two vertical turbine pumps each of capacity 750m3/hrare installed to give maximum dynamic head of 50m, when the working in parallel. The

discharge of both is combined through suitable slide and non-return valves and goes to

tailrace. One pressure gauge is also provided in common discharge line.

AIR AND WATER PIPE LINES:-air and water pipe line inside the turbine pits are provided serve for:-

Supply of air to the repair seal (inflatable type) provided under turbine sealing. Cooling water to turbine sealing. Drainage of leakage water by pump motor set from turbine top cover. Cooling water to labyrinth sealing during synchronous condenser operation. Air supply during synchronous condenser operation. Air supply during part load operation. Water pressure relieving from upper portion of crown. Cooling water inlet and outlet for guide bearing.

2.1.5 MAIN INLET VALVE:-

A) The butterfly valve is located on the pen stock before the turbine and serves thefollowing purposes:-

It stops the water entry to the turbine when the latter leakage is stopped for a longerperiod, to decrease the water leakage and to protect the guide apparatus against silt

cavitations.

It stops the water supply to the turbine in case of emergency.B)Normal closing of valve takes place in still water, but during emergency it is closed

against flow of water.


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C) Butterfly valve is installed in the power house building itself. During operation thevalve should be either completely closed or completely opened. Intermediate

position of disc to allow partial flow is not allowed.

D) Opening of the valve is carried out after equalization is done by supplying water tothe spiral casing through bypass valve, keeping the guide apparatus in closed

position.

E) The valve is operated by means of two oil operated pistons receiving oil from oilpressure unit.

F) The butterfly valve has got horizontal axis of rotation.G) A set of limit switches have been mounted on butterfly valve with corresponding set

of levers to operate of B.F. valve.

2.1.6 GOVERNOR

The accuracy and sensitivity of the order of 0.02% is desired so that as to assure that

several regulators behave in the same way for the system disturbances, thus avoiding mutual

hunting and over regulation. To meet above requirements it is, therefore, provided withmicro

processor based on electric hydraulic governor which should be able to perform speed control,

load control, intelligent sequencing a rapid system monitoring of hydro turbine with reliability

and precision. To ensure flexibility in the system there will be provision to change the reference

values like speed setting. Gate limit or position and parameter values of PID controller by

software means in addition to conventional hardware means.


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2.1.7 POWER TRANSFORMER

For each 42MW unit there are three power transformer of 52MVA, rating.

Transformer has two side HV and LV side, whatever side will be used as input or output. When

an hydro generator is in generating stage output voltage of generator is 11 kv, which is input to

power transformer and output of that transformer will be 132 kv which is feed to power grid

system at that time this transformer is used as step up transformer, but in case of power grid

failure power plants will be totally shut down then to start a unit of plant same transformer is

used to step down voltage from 132 kv to 11 kv. This 11 kv supply is given to UAT, UET of

plant to start machine of plant.


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2.1.8 POWER EQUATION:-

Every Power house has different power generating capacity. This is governed by factor

like water head level, discharge rate of water and the efficiency of the system.

Power, P= 9.81*q*h*

Where,

P= is power generated in KW

q= is Discharge of water (m3/sec)

= is overall efficiency of TG units

h= is net head acting on turbine in meters (Net Head=Gross Head-Losses in WCS)

Power calculation for each unit of LARJI power house:-Given data:-

Rated head = 56 m

Discharged of water = 83.33m3/sec

Efficiency = 0.9% to 0.95%

Power produced by each unit = 0.92*83.33*9.81*56 kw

= 42115.92 kw = 42 MW


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CHAPTER 3

3.1 HYDROGENERATOR

3.1.1 SPECIFICATIONS:-

Types of generator SV 806/083-36 Capacity (KVA) 46667 Capacity (KW) 42000 Maximum continuous output (KVA) 51334 Maximum continuous output (KW) 46200 Terminal voltage 11000 V Stator current2450 A Power factor 0.9 lag/lead Excitation current 1165 A Excitation voltage 140V Speed/no. of rotor poles 166.7 RPM/36 Frequency 50 Hz Direction of rotation Clock wise Types of winding Wave wound No. of slots 270 Height of stator frame 2150 mm Height of generator shaft 2384 mm Overall diameter of rotor 7264 mm Stator core inside diameter 7300 mm Pressure for cooling water 3-4kg/cm


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3.2 TURBINE


1. Type of turbine francis(vertical)2. Net head

Maximum 68.25m Rated 56.84m Minimum 53.80m

3. Rated output at rated head 43500 kw4. Maximum output at Rated net head 47850 kw Maximum net head 47850 kw Minimum net head 43500 kw

5. Discharge at rated output 81.86 m3/sec& rated net head

6. Speed Rated speed 166.7 rpm Run away speed 330 rpm

7. Direction of rotation when clockwiseViewed from top

8. Maximum speed raise 45%9. Maximum pressure raise 45% of max. static head10. Runner inlet diameter 3450 mm11. Guide apparatus

Elv. Of centre line 894.7 m P.C.D. of guide vane 4140 m Height\of guide vane 1092 m No. of guide vane 24

12.No. of blades 1313.Type of spiral casing metallic14. Elevation of lowest point in the draft tube 883.7 m


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3.3 MAIN INLET VALVE (MIV)


Type double seal lattice valve Diameter 4200 mm Design pressure 11 kg/cm2 Opening / closing time 60 sec Number and diameter of servo motor 2/450 Diameter of bypass valve 300 mm Diameter of air valve 200 mm


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3.4 GENERATORTRANSFORMER(132/11kv)


Type of transformer core type Rating HV(MVA) 52 Rating LV(MVA) 52 No load voltage HV (KV) 132 No load voltage LV (KV) 11 Line current HV (amp) 227.71 Line current LV (amp) 2732.53 Type of cooling OFWF Core/ winding (kg) 35000 Weight of oil (kg) 12500 Total weight (kg) 62000

3.4.2 GENERATOR TRANSFORMERS

Generator transformers of 52 MVA, 11/132 kv, 3 Phases, 50Hz rating is provided

and is place in different niches on has been providing. The transformer on 11KV side has

been connected to the generator through bus duct and on 132 KV side to SF6 GIS. The

transformer shall be equipped with protection equipments.


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3.5 UAT:- UNIT AUXILARY TRANSFORMER


Type of transformer dry type Capacity (KVA) 500 Rating HV (KV) 11 Rating LV (KV) 0.415 Rated current HV (amp) 26.24 Rated current LV (amp) 695.6 No. of phases 3 Frequency (Hz) 50 Ambient temperature 50 Temp. rise over ambient 90 Insulation class F Weight (Kg) 3400

3.5.2 FUNCTION OF UAT:-

These transformers are not oil type transformer, they are of dry type. Dry type

transformer is a step down and has rating of 5 KVA. All the auxiliary of machine such as carbon

dust collector, breaking system, MIV system, water cooling and oil pumping system have supply

from UAT. The input for UAT is from hydro generator, diesel generator and from power grid

system.


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3.7 STATION TRANSFORMER


Type of transformer core type Rating HV (MVA) 6.3 Rating LV (MVA) 6.3 Line current HV (amp) 27.56 Line current LV (amp) 330.66 No. of phases 3 Frequency (Hz) 50 No load voltage HV (KV) 132 No load voltage LV (KV) 11 Type of cooling OFWF Core/ winding (Kg) 14010 Weight of oil (Kg) 8680 Total Weight (Kg) 3480

3.7.2 FUNCTION:-

At starting time of generating unit when there is no power generated by generator in power

house. To start generating unit, we need power. At first power is taken from grid system through

station transformer, then synchronized the generating unit with grid. Station transformer supplythe power to all auxiliary machines of generating unit, within 3-5 sec. generating unit start

running and generate 11 kv the supply from the grid will cut off and this transformer taken

power from generating unit then all auxiliary machine get power from station transformer.


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3.8 BATTERY BANK

Battery bank is the main heart of the power house. Battery bank supply the D.C. power to

controlling and protection system of the power house, Liquid type of battery is used and are

connecting in series.


A) Lead acid cell plante:- Type YHP-21 Capacity 1070 AH Temperature 60C Total no. of cell 110 Each cell voltage 2 V D.C. Total voltage 220V D.C.

YHP-21 is a lead acid cell plante, which supply DC voltage to all DC panels (metering

panel) and protection relay of generator and transformer, circuit breaker open and closed,

lighting.

B) Lead acid cell tublar:- Type B-150S Capacity 150AH-10HR Temperature 210-270C Total no. of cell 24 Each cell voltage 10V D.C. Total voltage 240V D.C.

B-150S is a lead acid cell tublar, which supply DC voltage to remote optical fiber wires,

used in DC panel.

C) Dry cell:- type Type B-150S Capacity 760AH System voltage 26V Total no. of cell 13 Each cell voltage 2V D.C. Floating voltage 28.99V Boast voltage 29.09V Maximum charging current 152A

This cell supply DC voltage to microprocessor and data chip.


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D) Lead acid cell tublar:- Type T600H HDP Capacity 600AH-10HR Temperature 210-270C Total no. of cell 24 Each cell voltage 2V D.C. Total voltage 48V D.C.

T600H HDP is a lead acid cell tublar, which supply DC voltage to PLCC ( Power Line

Carrier Communication)

E) Dry cell:- Type T600H HDP Capacity 100AH Total no. of cell 120 Each cell voltage 2V D.C. Total voltage 240V D.C.

It is dry cell, supply DC voltage to computer.


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3.9 BATTERY CHARGER

3.9.1 48V DC PLCC Battery charger 1,2:-

A) Serial no. IS-3136B) Direct voltage

Float voltage 43-53V Boost voltage 43-64V

C) Direct current Float current 60A Boost current 100A

D) Type of load continuousE) Insulation class FF) Input voltage 41510%G) Phase 3H) Frequency 50 Hz

3.9.2 220 DC Distribution Board 1,2:-

A) Serial no. DB/18811B) AC input 41510C) Output voltage

Float voltage 236.5V DC Boost voltage 2.75V DC

D) Output current Float current 286A max. Boost current at starting rate 128A Boost current at finishing rate 64A

E) Phase 3F) Frequency 50 HzG) Max. operating temperature 50CH) Battery bank 110 nos. lead acid cell of 1070 AH


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3.10GAS INSULATED SUBSTATION TYPE F35

3.10.1 PERFORMANCE:-

Up to 145 kv Up to 40 kv short circuits Up to 3150A continuous

3.10.2CHARACTERSTICS:- Three phase in one enclosure Cast aluminium enclosure Spring mechanism

3.10.3CUSTOMER BENEFITS:- flexibility

space spacing, having compactness increased safety & reliability modularity and adaptability easier operation accessibility of components

3.10.4TECHNICAL DATA:- Type 3 phase, common metal enclosed Location underground/indoor Rated voltage (KV) 72.5-145 Rated frequency (Hz) 50/60 Rated normal current (Amp) 2500-3150 Rated short ckt current (KA) 31.55-40 Rated lighting impulse withstand Voltage (peak) (KV) 325-650 Number of phases 3 No. of bus bars 2 Material of bus bar aluminium alloy Insulation medium SF6


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3.10.5MAIN COMPONENTS:-

Main components are made of thermal effect circuit breaker with 3 single phases interrupting

elements contains in the same enclosure are:-

Ckt breaker/disconnector combining the functionality and performance of a ckt breakerand a disconnector.

High-speed earthing switch: moving contact driven by a spring charged during openingand closing operation.

Current and voltage transformers. Surge arresters. High-voltage interfaces: HV plug in cable connection and direct connection to power

transformer, over head line connection.

Local control cubicle.3.10.6FUNCTION OF GIS:-

The GIS type F35 is designed to withstand 40 KA, and the ckt breakers to interrupt the

full 40KA short ckt from 72.5 KV to 145 KV. They protect substation equipment,

transmission lines and power transformer, it acts as isolator between the line connected to

the power transformer. The single phase interrupting elements of thermal type are

contained in the same enclosure. The ckt breaker combined the functionally and

performance of a ckt breaker, a ckt breaker interrupting capability and a

disconnectorsdielectrical insulation with insulation co-ordination across terminal and to

earth.


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3.11 COMPONENTS

1) Dam / barrage Spillway, radial / vertical gates, sluice gates Power dam Intake

2) Silt flushing arrangement3) Head race tunnel / Head race channel (Open or Cut & cover)4) Penstock direct from DAM5) Surge shaft (Upstream of penstock)6) Power House Turbine Generator Transformer

7) Tail race tunnel / channel / tail pool8) Switchyard


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3.12 MAJOR COMPONENTS OF POWER HOUSE

1) Water path Inlet valve Spiral casing and turbine Draft tube

2) Governor3) Generator4) Excitation system5) Unit auxiliary transformer6) Bus duct7) Generator transformer8) Unit control board9)

Control & protection

10)A.C. Supply System11)D.C. Supply System12)Cooling water system13)Compressed air system14)EOT crane15)Ventilation system and air conditioning16)Drainage and dewatering system17)Fire protection system


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3.13 SWITCHYARD COMPONENTS

1) Circuit Breaker2) Isolator3) Earthing switch4) Current transformer5) Potential transformer6) Lightning Arrestor7) Bus Bar8) Control & relay panel


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CHAPTER4

OPERATION AND MAINTENACE

Operation and Maintenance of hydro power stations must aim at reducing failur e rate byensuri ng smooth operational levels of the power uti li ty. Thi s can be done by adopting timely

preventive maintenance schedule regarding al l vi tal areas of the power project. Engineers are

well -advised here to foll ow the well -known dictum

Prevention is better than cure.

4.1Hydro Power Plant Engineering : Major component of hydro electric

power projects:

A typical Hydro electric power project is spread in a vast geographical area. Depending on thedesigns of the project, it may be spread over 30 to 50 Km of area. In the vast geographical area,

there are large number of critical component which make a hydro electric project works. In this

blog post I am going to briefly describe each and every part of those component.

Figure 4.1 Water conductor system.
http://hydropowerstation.com/?p=364http://hydropowerstation.com/?p=364http://hydropowerstation.com/?p=364http://hydropowerstation.com/?p=364


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4.1 DAMS:-The most important aspect of hydro power generation is to ensure that the plantcontinue to function continuously. The main component of hydro power project is dam, whichmay be concrete gravity, rock filled, earthen or combination of some of above types. Earthen

dams differ from masonry and concrete dams due to relatively greater deformability and higher

permeability of earth masses (excluding plastic clay hearting). As these dams are big in general,

The safety of the dams is most vital for the unhindered performance of the power plant.

4.2 BARRAGE:-The diversion structure like barrage and weir are generally designed on theprinciple governing the percolating of water below the foundation of the structure. The floor of

the structure is suitably designed either as a raft of gravity section to be safe against the uplift

pressures created.

4.3 WATER INTAKE STRUCTURE:-A structure to divert the water to waterway,which includes trash racks, a gate and an entrance to a canal, penstock directly to turbine

depending on the structure of the project.

4.4 HEAD RACE TUNNEL/POWER CHANNEL:-A canal, tunnel and/or penstockcarries the water to the power house. Sometimes a desilting chamber precedes the head racetunnel, which remove the larger size sediments from entering into the tunnel.

4.5 SURGE SHAFT:-Surge tank is provided into water conducting system primarily toreduce the surge pressure to be considered in the designed penstock/ pressure shaft. This

economizes the design of penstock/ pressure shaft justifying the extra cost for the provision of

the surge tank. The provision of the surge tank has following advantages:

The length of the column of water gets reduce by placing a free water surface close to theturbine.

It act as a pressure relief opening to absorb surplus kinetic energy. It acts as a balancing reservoir to supply/ store additional water during starting/ closure of the

gates/ valves.A surge tank absorbs the water hammer effects due to rapid start or closure of the

turbine.

4.6 PENSTOCK/PROTECTION VALVE:-The penstock valves are provided after thesurge shaft to facilitate maintenance of the penstock. These valves are butterfly valves. The are

butterfly valves are operated hydraulically with provision of pressure accumulated in case of

power failure.

4.7 PENSTOCK/ PRESSURE SHAFT:-The penstock convey the water to the powerhouse and can take many configurations, depending upon the project layout. Where the powerhouse is an integrated part of the dam, the penstock is simply a passage through the upstream

portion of the dam. In case of project having long head race tunnel terminating in the surge tank,

the penstock from the surge tank, where most of drop in elevation occurs, would be apressurerized tunnel or pipe. For multi unit installation, it is often desirable to surve several units

with a single penstock, and manifolds or bifurcation structures are provided to direct the flow to

individual units.


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4) Operating conditions should continuously be monitored and recorded.Records are veryimportant to diagnose the causes of fault / failure/replacement & to determine residual

life. Early action can be takenbefore any type of failure.

5) Eventhough Original Equipment Manufacturers recommend max./min. permissibleparameters for their equipment, the records/experience/past history play important role to

set limiting values ofparameters of these equipment, as characteristics of

identicalequipment vary from unit to unit and required to monitor its set values.

6) On the basis of past history/records & recommendations of OEMsmaintenance schedulescan be framed. Breakdowns/forced outagescanbe minimized by proper follow-up of the

maintenance schedulesbased on recommendations of OEMs.etc. Life of the equipment

thuscanbe enhanced.

7) Starting/stopping of the units shall be planned to be minimum toincrease the life.8) Procurement of the equipment spares should be planned as per therate of the consumption,

based on minimum requirement to optimize the inventory.

9) Optimum utilisation of the men & material to be planned.10)It would be beneficial to arrange training to O&M staff to refresh theirknowledge and to

give advanced technical information to improvework quality & quantity.

11)Interaction amongst working staff at various power stations in thecountry needs to beorganised to improve performance of plant andequipment in totality so as to implement

good Operation &Maintenance Practices.

12)Provision of On Line Condition Monitoring System on genenrator,214turbine and maintransformers could be considered for installationon all existing power stations.

13)Afforestation in catchment areaCatchment Area Treatment studies for the Stations inoperation could begot carried out and as per recommendations of the studies, the

PowerStation should carry out afforestation work in the catchment area. Thiswould help in

reduction of silt content in the inflow water.


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4.2MAINTENANCE PRACTICE:-

Some of the practices to be adopted at hydro power stations for maintenance of certain mainplant are broadly given below.

4.2.1 Water Intake, Water Conduit System and Associated Equipment Water storage

(Reservoir) & water conductor system comprising of intake, head race tunnel, surge

shaft, emergency valves & pressure shafts, penstock, main inlet valves are very vital

organ of a hydro power plant. .Due to negative and positive water hammer during sudden

changes in water flow, it is essential to attend to these plant & equipment very carefully.

It is very important to regularly test operation of conduit isolation system/equipment i.e.

intake gates, butterfly valves, excess flow device, surge equipment etc. Periodic

physical inspection of water conductor system from inside as well as outside to know itscondition, silt deposition, rusting/erosion of conduit system is very much essential to find

out various changes due to aging factor, stresses developed due to water hammer etc. The

records of such physical inspection should be maintained by noting all the details:-

i.e. normal as well as abnormal. These records can be compared withthe installation data.

Any abnormality is to be further investigated bycarrying out hydraulic testing,

measurement of thickness by Ultrasonictesting& tests for measuring and computing

stresses at strategic locationssuch as intake point, bends, besides observing sudden

changes inelevations& sizes of pressure shafts, penstock etc. Leakages, if any,should be

scrupulously noted and records maintained. It should be215ensured whether inside /

outside (wherever possible) painting is carriedout to protect the conduit system. The

valve seals, if deteriorated shouldbe replaced by using new seals with latest materials for

enhancing thelife of this equipment. Purification and frequent testing of hydraulic

systemoil should be carried out as per recommendations of the manufacturers.For oil

purification on-line electrostatic liquid cleaners may give bestresults. Some of the

additional points as mentioned below also need tobe considered:-

Cavitation & erosion at top portion due to rushing of air during fill up. The inspection schedule for the durability of anticorrosive paints used. Replacement schedule for various vulnerable parts such as bends,open conduits etc. Due to humidity open conduit deteriorates from outside. As suchinspection& cleaning to

be carried out from time to time at regularintervals.

Anticorrosive-painting schedules followed. Timely Operation & Maintenance of the cranes & hoists. Healthiness of control & protection for isolating gates/valves &forcranes/hoists. Maintenance of trash-rack/intake gate filter.


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Maintenance of communication systems, availability of power supply,equipment foremergency operations, approach roads etc.

4.2.2 TURBINE& ITS AUXILIARIES:-

Regular inspection of runners of turbines should be carried out and recordto that effect should be

invariably maintained. Many a times it is notpossible for Francis Turbine being always immersed

in water and needsisolation on either side. For this it is done as recommended bymanufacturer

without any compromise. Due to cavitation there maybehuge damages to turbine wheel causing

adverse effect on performanceand consequently efficiency. Sometimes, it would be necessary

toundertake in-situ repairs of turbine buckets to recoupe/fillup erosions/white pitting by using

various cold compounds viz. Belzonacompound,Loctite, SS Metalset, Throtex compound etc.

This may give satisfactory216results. Low heat input welding can also be tried at some of the

locationsto some extent.

An effective system for monitoring of silt content (quantity and size inPPM) may be installed &

commissioned by each power station and siltcontent may be monitored continuously on the basis

of which action tomitigate the damaging effect to under water parts may be initiatedreducing the

down time of units / station.Best efficiency microprocessor based digital PID speed

governorsprovide fast response. Periodical maintenance of speed governorsalongwith all

associated mechanical, electrical, electronicscomponentshould be carried out. The control circuit

should be neatly dressed withidentification marks. The electronic components and cards should

becarefully maintained at appropriate temperature level to achieve desiredperformance.

Periodical calibration and testing of transducers, metersNew Turbine Runner of Unit No. 3 of

Burla Power House of HirakudPowerSystem being replaced for RIM & U Works.217etc. needsto be done. Desired purity level of hydraulic oil is to bemaintained to give trouble free

operations. History of each important partshouldbe maintained. Following maintenance works

also need to betaken up:-

TURBINE:-

Periodic NDT viz. Ultrasonic, etc. Polishing of the various under water parts of the turbines once in a year to minimize the

white pitting.

Inspection & testing of the runners from experts to decide residual life so as to initiateaction for procurement of runners for replacement.

Inspection of labyrinth seals in case of reaction turbines. Painting of runner housing with anticorrosive I tar based paints. Applying anti-erosion coating to the runner.

Checking of brake jet operation in power stations having Pelton turbines once in three months.


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GOVERNOR:-

Purification of hydraulic oils by centrifugal as well as electrostatic liquid cleaner. Periodic maintenance of the servo valves and motors after carrying out inspection of the

pistons & housings of the servo valves and motors for their worn-out parts. Replacementof the leaking seals.

Survey of the component failure & procurement of the same and maintain minimuminventory.

4.2.3 GENERATOR & ITS AUXILIARIES:-

Stator & rotor winding, bearings & excitation system are the main partsof a generator. As

regards stator and rotor windings, regular recording ofIR Values of these winding should be

maintained at regular intervals.Tan Delta and DLA tests of stator winding indicates the status I

conditionof stator winding insulation. Likewise impedance test (voltage drop testacross eachpole) indicates condition of the rotor winding. Proper coolingsystem is to be maintained to limit

rise in stator winding temperaturesand consequently increase the life of stator winding.

Inspection of the218stator winding is also required to be carried out to verify its firmness instator

core slots and healthiness of overhang portion with firm end windingcaps& end spacers, slot

wedges checked for healthiness. Windings arerevarnished to enhance their life. Looseness of

stator core or interlamination, core insulation are direct factors affecting winding heatingdue to

eddy current loss. Thus recommended maintenance as perschedule should be carried out its

records maintained and correctiveactionsbe taken if necessary.Another precision and very critical

components of generator are its guideand thrust bearings. The thrust bearing is main bearing

holding completethrustof rotating mass of turbine and generator unit. The generator andturbineguide bearings act as guides for controlling the vibrations of theunit . If T -G shaft alignment

with accurate shaft level is achieved then thepad clearances are adjusted precisely and the

rotating machine willoperate smoothly without rise in bearing temperature and increase

lifeMachine Hall of Bhabba Power House 3x40 MW219of bearings. Following works also need

to be taken up:-

Periodic checking of the foundations, tightening the bolts. Filling thefoundations withepoxy.

Checking the vibrations periodically & history of the recordedreadings gives guidelinesfor realignment, looseness if any,unbalanced electrical components, increase in bearinggaps,coupling misalignment, uneven stator -rotor air gap etc.

Periodic cleaning or replacement of the generator air coolers andbearing oil coolers toimprove performance of the generator.

Primary and secondary testing of the protection system for itshealthiness and correctoperation.

Inspection of the CTs, PTs and bus bars for overheating, temperaturerise etc.


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Inspection of circuits for protection & control circuits & mock trials of the fire fightingsystem along with evacuation system. Checking weightloss of the CO2 cylinders and

replenish as per recommendations ofOEM.

4.2.4 TRANSFORMER & SWITCHYARD:-

Continuous monitoring of oil & winding temperature. Periodic oil filtration. Oil testing for various tests and Dissolved Gas Analysis. Tandelta& insulation resistance etc. as per schedule. Cleaning and replacement of oil cooler Testing protection system for healthiness. Mock trials of Checking, maintenance and inspection for Fire fighting system, CO2

&mulsifire.

Tests for operation time of the breaker. Operation & testing of isolator opening & closing. Checking of control circuit & healthiness of operating system of thebreaker.220 Periodic cleaning of transformer bushings & insulator strings. Switchyards are to be kept neat & tidy. Minimum area surrounding theyard to be free

from growth of scrubs and bushes to avoid any bushfire damaging the equipment.

4.2.5 EMERGENCY D.G. SET:-

Regular maintenance of the emergency set. Checking control & Protection system. Running of DG set at regular intervals.

4.2.6 OTHER P.H. EQUIPMENT:-

Periodic maintenance of unit auxiliary, station auxiliary &stationService transformer. Checking healthiness of station batteries & battery chargers.TheTwo charges should be

rotated once in a week.

Regular inspection of cable ducts to ensure proper ventilation / heatDissipation. Checking the healthiness of pressure relief valve, if provided.


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CHAPTER5

CONCLUSION

HPSEBL is committed to provide adequate, reliable power to all its consumers and in thisdirection all out efforts are afoot.

HPSEBL is also committed to ensure Grid discipline & operate with in a frequency bandof 49.5Hz to 50.2 Hz.

To achieve the above aims we seek the support & cooperation of our Industrial brethren.

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