kocolung khola electrification project

8/13/2019 Kocolung Khola Electrification Project

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Detail feasibility study report of Koksulung khola electrification project, Udayapur.

Consultant: Nepal Power Solution Pvt.Ltd. 2

The survey team didnt feel the insufficiency of the instrument and equipment. Andhence the result is the acceptable surveying data and other information.

The Abney level is used for the canal route alignment and head

measurement. 3 meter measuring tape and Plastic Bucket of 25 Liter is used forthe discharge measurement by Bucket method and 50 m tape is used for thecanal length measurement and transmission & distribution length measurement.The equipments used are listed below:

1. Abney Level

2. Level Pipe

3. Measuring Tape 50 m & 3 m

4. Plastic Ball

2.0 Methodology

The detail survey was done with the help of an Abney Level, Level Pipe of15 m length, 50 m and 3 m measuring tape and Plastic Ball of 20 mm diameter.The detail survey was done within the principles of leveling. The canal alignmentand the head were measured with the help of Abney level. The flow measurementwas done by area velocity method of discharge measurement. The discharge wasmeasured by using measuring tape and plastic ball. So the result of area velocitymethod has been included in this report. The length of the transmission anddistribution was measured with the help of 50 m tape.

A meeting with the Developer, Pico-hydro users, the Koksulung kholaelectrification Users Committee (UC) and active personals of that area was heldduring site visit. The socio economic details and other information are outcome ofthe interaction meeting. The detail survey was then carried out with the help of themembers of the functional groups. The following procedures were adopted duringsite surveying:

Site observation with officials/community people to locate and select

suitable site.

Flow measurement using velocity-area method.

Site survey of different components e.g. intake, headrace, forebay,penstock, powerhouse and transmission/distribution line.

Calculation of output power and discussion with community to meet

the approx. demand.

Discussion on end use possibilities.

Discussion on possible socio-technical and environmental problems

associated with the scheme.

3.0 Power/Lighting Demand


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The people of the electrification area are totally dependent in the firewoodand Kerosene for the cooking and lighting. Hence electricity is the basic need forthe villagers to overcome form the traditional lighting track. The scheme isdesigned to get maximum power output during whole period of time in the year.The electricity thus generated will be distributed to Choundady VDC-1, Ranitar. Tofulfill the energy demand of the community people this electrification play a crucialrole by the use of nearby unused natural resources.

The surveyed households in the electrification market are 40. And all the 40households are included for the proposed scheme. So, there are 40 householdswith 237 members @ 6 members in each household will be benefited by theimplementation of this project. The average power allocation for each household is100 watt. So the total power to be developed is 4.03 kW. Considering the losses(12%), total power developed from the Pico-hydro is 4.03 kW. So the developmentof 4.03 KW from the Koksulung khola electrification project is justified.

4.0 End Use Possibility

There are varieties of agricultural products like maize, millet, potato andoilseeds. For the processing of these agricultural products, two agro-processingmills are required. People of Ranitar use the turbine for the agro processing. Sothere is too much agricultural product, mostly maize and millet. There areagricultural products such as maize, millet, potato and oilseeds more than 800Muris per annum. Main income source of the people of that area is foreignemployment and agricultural product. So the installment of agro-processing mill isjustified. Also the area has the potential of saw milling and Oil expeller.

S. No. Type Power Operation Period

hours/day Days/yr.

1 Agro-Processing 500 watt 6 330

2 Saw mill 1500 watt 3 180

3 Oil expeller 2500 watt 4 200

Also saw mill for the local carpentry is required. The saw mill require 1.5KW mechanical power developed by the project. The mill will run at an average 7hours per day and 180 days per year. The oil expeller needs 2.5 kW mechanicalpower.

5.0 Multiple use of water

There is a possibility to use water for irrigation from tailrace cannel. Wetake 100% water for electrification at the time of feasibility study.

6.0 Hydrology


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The proposed Koksulung khola electrification uses the water fromKoksulung khola . The total measured discharge in the river in the date of 7-F-2068 is 100 l/s. To measure the flow in the river the area velocity method wasadopted.

The flow of the Koksulung khola is found to be 14 l/s and hence the designdischarge is taken as 18 l/s as per required of power . According to the powerdemand, the available discharge is insufficient. To collect and maintain requireddesign discharge fore bay reservoir tank is proposed for the plant.

7.0 Discharge and Head

The design discharge is taken as 18 l/s as per required of power according tohouseholds. Gross head of the scheme is 38 m with overall efficiency of 60 %. So

the total power output of the plant is 4.03 kW. As there are 40 beneficiaryhouseholds in the electrification market and average power allocation for eachhousehold is 100 watt. So the total power requirement of the market is 4.03 kW.Considering the losses, the power generation of 4.03 kW is justified. The powergenerated is calculated as:

Power (P) = (*Qmin *Hg) /100= 4.03 kW

Where,Q = Discharge in l/s (18 l/s)

H = Gross Head in m (38 m) = Overall Efficiency of System (60%)

8.0 Technical Design

8.1 Civil components

8.1.1 Intake/weir Structure and Gravel trap

The intake structure is located at left bank of Koksulung khola . It is locatedat Ranitar village, Choundady VDC-1, Udayapur district. The width of the river atintake site is 1.5 m. There are medium sized boulders at both bank of the river. Soit is located in the stable geology. It is suitable location for the intake. Inconsideration of the flow of the river, temporary type diversion structure using drystone and other locally available materials is designed. The height of the diversionstructure is designed to be 0.28 m.

There is need of trash rack. The existing trash rack has followingspecification:

Bar thickness = 3 mm

Clear spacing = 50 mmAngle of inclination from horizontal = 60 degrees

Size of thrash rack = 0.5 m x 0.5 m


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8.1.2 HeadraceCanal

The entire alignment passes through the left bank of Koksulung khola .Total of 800 m existing canal will be repaired i.e. it should be of plastered stonemasonry with 1:3:6 PCC over that. The canal section will be of 0.2 m*0.2m is to becontinued to forebay. The details are shown in drawing.

.The canal alignment is also facilitating with drop and cascade structures.

The respective locations are shown in canal profile and detail features are shownin drawings. The canal passes through the cultivated field. The soil type is claymixed with sand.

8.1.3 Forebay Reservoir TankThe forebay is located the end of headrace conveyance. The Forebay is

designed to settle the particles greater than 0.3 mm and store the requireddeficient discharged required for the plant. The Koksulung khola has relativelyless sediment concentration. The length of the basin is 13 m and width of thebasin is 5 m internally.

The structure is constructed of 300 mm dry stone soling at the base and100 mm PCC (1:2:4) over that. The remaining structures i.e. walls are of stonemasonry in 1:4 c/m with 12.5 mm inner wall plastered with 1:4 c/s. A fine trash

rack of 1000 mm x 1600 mm is required at the forebay. The trash rack is placed at600inclinations. The forebay is designed so that it can hold the water required tofulfill the deficient discharge for the plant collecting during shutting down the plant .

The flushed water goes back to the Koksulung khola through the existinggully. The size of the flushing canal is 0.50 m x 0.55 m as shown in drawing, whichjoins the Forebay to the existing gully. The length of flushing canal is 15 m.

8.1.4 PenstockAlignment

The penstock alignment is chosen to be in stable geology. There is nohorizontal bend and no vertical bends. There is uniform slope in the penstockalignment. The inclination of the penstock is 200from the Forebay and continuesup to the last anchor block. The length penstock pipe is 3 m. High densitypolythene pipe of 160 mm diameter is proposed for the penstock pipe .

8.1.5Powerhouse

The powerhouse is proposed to be located on the cultivated field. It is aprivate land. But there is no conflict on using the land for construction ofpowerhouse. It has sufficient space to build the house. The powerhouse is

sufficiently above the flood level and need no protection measure.

The powerhouse consists of internal dimensions of 5.0 m lengths, 4.0 mwidths and 2.7m heights. The building is to be built of locally available stone


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masonry walls with C/S mortar and cement plaster on the inside surface. The baseof the power is constructed by 100 mm stone soling over compacted earth and 75mm PCC (1:2:4) over that. The roof is to be covered with CGI sheets with woodenrafters and Purlin. For details refer drawing powerhouse.

8.1.6Machine Foundation and tailrace

Machine foundation has been designed as required to be in safer sideagainst over turning, bearing pressure and sliding considering the forces due tomaximum expected surge head, weight of turbine. Runner is foundation onmetallic foundation bolt with nut tighten. The size of foundation bolts is 400 mmmade by 12.7 mm or inch metallic bolt.

Structural concrete shall be 1:2:4 mix. 10 mm width of sand and gravel hasbeen placed at periphery of metallic legs down to depth of powerhouse floor. The

detail of machine foundation is shown in drawing Machine Foundation.

The tailrace canal section has to be constructed from powerhouse toKoksulung khola . The capacity of the tailrace canal is 120 l/s. The alignment oftailrace canal is as shown in general Layout.

8.2Mechanical Components

8.2.1 TrashRacks

Coarse trash rack at intake is required to protect logs and larger waterborneobjects from entering the canal. For intake, coarse trash rack of 0.6 m x 0.4 msize, 10mm rod for bracing and 3 x 20 steel vertical strips with 50 mm spacing arethe main specification of existing trash rack. Trash rack is also proposed forforebay to protect twigs, leaves and branches for entering penstock. Fine trashrack of 2.6 m x 1.6 m size, 8 mm rod bracing and 5 x 25 steel vertical strips isproposed. The spacing for the trash rack in forebay should be 15 mm.

8.2.2Penstock Pipe

A HDPP penstock pipe having 160mm has been proposed for our

scheme. The inclination of the penstock is 100with horizontal from the Forebay upto the last anchor blocks. There is uniform slope in the penstock alignment. Totallength of the penstock is 300 m. Air vent pipe is provided in penstock pipe afterleaving the forebay tank.

8.2.3Valves

Valves are required to control the flow of water entering into the turbine.

Whenever there is any problem in the turbine/ generator, the valve stops the flowof water immediately. A butterfly valve gear operated type of 160 mm diametersize ahead of the turbine is proposed to stop the flow of water in penstock pipe.


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8.2.4Turbine

The scheme has gross head 38 m and design flow is 18 l/s. So the

generated power is 4.03 kW. For this purpose, cross flow turbine is recommended.Though the each manufacturer has own design and product specification. (Detaildesign will be as per the manufacturer at the time of manufacturing with requiredoutput.)

8.2.5 DriveSystem

The drive system transfers the mechanical energy from the Turbine shaft tothe generator rotor at required speed. Here, the rated speed of the generator is1500 rpm. It is belt drive system type so manufacturer design according to theirown requirement.

8.3 ElectricalComponents

8.3.1Generator

A single phase induction generator of 4.03 KW is proposed. The generatorsize and type should be compatible with the electronic regulation system i.e. IGC.The construction and bearings of the generator should be rated to withstandrunway speed under fault condition. The bearings should further take the staticload exerted on them by the drive system. The proposed generator has following

specification:

Type : Single phase induction GeneratorCapacity : 4.03 KWSpeed : 1500 rpmFrequency : 50 HzPower factor :Nos. of pole :Generation Voltage : 220 VConnection : StarOver Speed : 100% continuously

Bearing : Grease lubricated ball bearings duty.

8.3.2 GoverningSystem

The Induction Generator load controller is recommended to maintain thespeed and frequency of electricity generated. Ballast tank is used to release theover power generated which is not being used so that the generator is alwaysoperated in full load. The IGC (Induction Generator load controller) of 4.84 kWcapacity is used with the ballast load of 4.84 KW single phase/220V.

8.3.3 Control andProtection System

The powerhouse generator is protected against over/under voltage andover/under frequency. Over/under voltage is protected by Automatic Voltage


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Regulator of the Generator. A Main Distribution Box (MDB) of 32 A consisting ofone main and two sub MCBs is proposed to isolate the faulty circuit either duringoverload or short circuit.

9.0 Transmission anddistribution

9.1 General

Transmission lines are suspended overhead on poles. Total quantity fortransmission and distribution wire-length of different squirrel type will be 700 m.There are 18 poles needed for the transmission and distribution. The transmissionof the power is done with in the limit of voltage drop of 10%. The numbers oflightning arresters used in transmission and distribution are two. Clear height of4.5 m from ground is recommended for the transmission and distribution. The typeof squirrel conductor length and overall transmission and distribution pattern has

been shown in drawing entitled transmission/ distribution lines.

9.2Poles

18 nos. of wooden poles are required for the transmission and distributionof the electricity. All of the 18 nos. of poles are of 7 m height wooden poles. 7 mheight wooden poles are used for transmission/distribution 2-wire system andsingle phase. The poles have to be buried for at least 1.5m below the ground levelfor the 7 m wooden poles.

9.3Stay set

Stay sets are required at every bends, first pole and last pole of thetransmission and distribution. The stay set consists of MS rod, stay bow, stayinsulator, check nut thimble and anchor plate. There is need of 5 numbers of staysets. Stay rod of and stay wire of 7/8 SWG is proposed to be used.

9.4 LightningArresters and Earthing Plates

Lightning arresters are provided to protect the electrical equipment fromdamage due to lightning. This equipment protects the electrical equipments fromhigh voltage due to lightning. In 400V/230V transmission and distribution 0.5 kVlightning arresters are required. So, there is need of 3 number (Sets) of 0.5kVlightning arresters in the whole system. The position of the lightning arrester isshown in the drawing transmission and distribution lines.

600mm x 600 mm copper Earthing plates of 3 mm thickness are recommended forthe Earthing of the electrical equipments. There is need of 4 nos. of EarthingPlates. The Earthing plates are to be buried at least to a depth of 2.5m.

9.5 Insulators, D-iron Clamp and DO fuse

There are 30 numbers of medium sized shackle insulators and samenumbers of D-irons. The insulators are proposed.


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9.6 Service wireand Current limiting Devices

At an average of 40 m per household, 2000 m long service wire is required.

The service wire is of 6 mm2. But wiring in each household is to be done by theowner. So the cost of the household wiring is not included in this report. For theprotection from fault, 0.5A MCB is proposed. So there is need of 50 numbers ofMCB of 0.5A. The proposed MCB has following specification:

Required Numbers : 50

Breaking Current : 0.5A

Operation Voltage : 400/230V

Operation Temperature : -50C to 400C

Rated short-circuit capacity : 3-10 KA Insulation Voltage : 500 V

9.7 Powerhouse andhousehold wiring

As stated above, the household wiring is to be done by the owner. So thecost of household wiring is not included in this report. However, the householdwiring is to be done by 3/22 wire for phase and 1/18 for neutral.

10.0 Socio-economic Status

The ethnic groups Magar, Rai, Shrestha, Sunuwar, Bhahun, Chettri & Dalit residein the area. The people in this area are economically poor and the main source ofincome is mainly agriculture. The literacy rate of people residing in this area isvery low. Almost all people in the area are unemployed and income fromagriculture is for 3 to 6 months. Hence the people in this area is needed of thisproject for the improvement of lifestyle and generate jobs for some people.


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11.0Environmental Status

The project is at Choundady-1, Ranitar, Udayapur. To mitigate the adverseeffects on bio-diversity, only 100% of the water take for electrification project. Asthe discharge in the canal as well as rivers is small, hence there is not anyproblem of landslide that may cause due to the seepage.

Environmental problems in Nepal are the result of mismanagement of naturalresources evolved from the lack of integration of environmental considerations inthe development process. After implementation of Pico Hydro, the socialsituations, community facilities, employment opportunities, land price and market

for local produce will increase automatically. There will not be considerablebiological impacts such as effects on vegetation and forest resources, wild life,crops, aquatic life etc. The implementation of project will not cause physicalimpacts such as floods, landslides and deterioration of soil. So the project doesntrequire any in-depth assessment on environmental impact. However the projectneeds some wooden poles and woods for door and windows that are planned tobe obtained from community forest of the areas.

12.0Management

The success of a project depends on its operation and management.Considerable benefits can be obtained from Pico Hydro if it is operated properly. Itis a community managed Pico Hydro and owned by Koksulung kholaelectrification Users Group. The management committee has not been formedand also the operator has not been selected yet. He has same type of experienceand with the medium managerial and entrepreneurship skill; the Manager hasability to manage the Pico Hydro properly. And operator training is necessaryalthough the operator is not selected yet. The management of the project will beas shown below.

Fig: Organization Chart

Operator-1

Users Committee

Operator-2

kocolung khola electrification project

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