Micro Hydro

TRIBHUVAN UNIVERSITY INSTITUTE OF ENGINEERING Central Campus, Pulchowk Lalitpur, Nepal Department of Electrical Engineering

A field visit report on

Micro-hydro power Submitted by: Deepak Bhatta

(069/BEL/315)

Narayan Shrestha (069/BEL/324) Pradip Khatri

(069/BEL/328)

Saroj Sapkota

(069/BEL/338)

Umesh Pudasaini (069/BEL/347)

Submitted to: Er. Dinesh Ghimire

August 27 2016

ABSTRACT The main target for field visit to Malekhu micro hydro power plant was learning the operation, commissioning, design and technical aspects of the micro hydro power plant. The one-day program of the field visits to Malekhu Hydropower, Mahadevbesi made us familiar with the social, economic benefits to the local people. During the visit we measured the head by two methods: water filled tube and sighting meter method and discharge by using two methods: area velocity and salt gulp method. A small discussion and questioning-answering about the installation, construction, improved socioeconomic status was also carried out during the meeting held among our visit group and committee. All the economic status of the micro hydro was evaluated. The problem that they normally face and their periodic maintenance routine were discussed. The micro hydro plant has brought a lot of change in the villagers with development like transportation facility, access to good health service, good education facilities and increase in living standard. Total of 310 household are getting benefits from this micro hydro plant. It has already been 5 years of its successful operation and it has showed its effect within this period and is seen technically and economically feasible and viable.

ACKNOWLEDGEMENT

We would like to thank our respected teacher Er. Dinesh Ghimire for providing us an opportunity to gain the practical knowledge about technical aspects of micro hydro plant through this field visit. Secondly, we would like to express our special thanks to Department of Electrical Engineering, Central Campus Pulchowk who managed the wonderful field visit. We would like to express our gratitude towards Madhusudhan Shrestha sir of Department of Electrical Engineering,Pulchowk Campus for his supervision and assistance in Micro hydro field visit. We would like to express our sincere thanks and gratitude to working committee of Malekhu khola Micro Hydro Power plant for explaining the system available there and providing the knowledge that we need for our study without which the visit would not be as successful. Also we are thankful to our respected teacher Madhusudan Shrestha for his valuable time and support to us. Also, we would like to thank all the teachers, friends and everyone who is directly or indirectly associated to make our visit successful.

INTRODUCTION In context of Nepal, micro hydropower plant is a small scale hydropower plant of capacity 5 kW to 100 kW usually located in remote areas where there is no direct access to national grid that may be due geographical difficulties and economically unfeasible. Micro hydropower plant is the major source of energy in the rural areas and it is a practical and cost effective way of meeting the energy demand of people in rural areas. We visited the Malekhu Khola MHP of 26KW located at Mahadevbesi VDC, Dhading. There are middle and lower class villagers living together with dominatingly Chepang community and others people residing over there are Magars and Gurungs. Most of the villagers there are engaged in agriculture. The micro hydro plant has brought a lot of change in the villagers with development like transportation facility, access to good health service and increase in living standard. OBJECTIVES  To learn operation, maintenance and design aspect of micro-hydro power plant.  Flow and head measurements in actual site. Micro-hydro plant design with measured discharge & head.  Sizing and selection of turbine and generator.  To design appropriate ballast size.  To find out the total capital cost investment and calculate the cost per KW.  Socio-economic development in the society due to Micro-hydro Plant. METHOLODOGY BEFORE FIELD VISIT:  Site selection.  Collection of documents and equipment to facilitate the visit. DURING FIELD VISIT:  Brief study of present scheme i.e. civil, electrical, mechanical etc.  Measurement of head and discharge by various methods.  Meeting with local peoples, interactions and questioning-answering etc. AFTER FIELD VISIT:

 Necessary calculation & selection of various components is done for designing.

Socio-Economic Condition Ethnic groups: There are 310 households, which are benefited from this MHP scheme. The total population benefited by this project is about 1500. Communities like Tamang, Chhetri and Damai/Kami,brahaman are residing in the project area. chhetri holds the majority of almost more than 65% but other communities also are in same respect. Economic condition Economic condition of the village is not very sound. Illiteracy percentage is high. The main source of income of the people is agriculture. Almost 90% household depends upon agriculture. In average 4 persons per household are involved in agriculture. About 10% household depend on labor works; in an average one man per household is involved. Land holdings and uses Average land holdings per household in the project area are 5 ropanies. The major crops grown are rice, maize, wheat, millet, oilseeds etc. besides potatoes, garlic, beans and orange are major horticultural crops grown in the vicinity. Canal utilization on irrigation purpose The main crops grown in the vicinity are rice, maize, wheat and vegetables. Implication of irrigation has increased the land yield. The water output for irrigation purpose is designed to be 12 l/s. with this large land has been irrigated under different cropping pattern. Marketing and agricultural commodities Farmers growing cereal crops generally get their cereal products milled at an agro-processing unit (Ghatta). Farmers engaged in vegetable growing sell their products to local main bazaar malakhu and products go to Kathmandu also for which middlemen plays significant role in determine price of the commoditized.

TECHNICAL DETAILS OF MALEKHU MICRO HYDRO PLANT Gross head 25 m Measured flow

350 l/sec may 1

Available flow

334 l/sec (driest flow)

Design flow

210 l/sec

Design power

26kW

Head race

1464 m, stone masonry

Diameter of penstock pipe

325 mm 3 mm thick and 50 m long

Types of penstock pipe

Mild steel

Types of intake

Side intake

Types of diversion

Temporary weir

Types of turbine

Cross flow

Turbine shaft power

40 kw

Mechanical transmission

Flat belt (habasit)

Generator

50 kVA,50 Hz synchronous generator,400/230 volt and 1500 rpm

ELC

26 kW

Ballast load

Industrial immersion heater 35 kw

Total length of transmission and distribution

10700 m

Types of conductor used

Rabbit conductor 17600 m and squirrel 20700 m

Name of the project

Malekhu khola village electrification project

Location

Mahadevsthan vdc

District

Dhading

Zone

Bagmati

Name of the source

Malekhu khola

No of house hold

310

Subscribed power

100 watt

Load centre

Ward no 1 2 4 and 5 of Mahadevsthan vdc

Route to reach site

Kathmandu- Malekhu (5 hours of walking)

MEASUREMENTS The Measurement of discharge can be performed through the following techniques: - Direct method 1.Area velocity: 2. Dilution techniques -Indirect methods: 1. Hydraulic structures –Weir 2. Slope area method The methods generally used for flow measurement are: 1. Velocity Method. 2. Salt gulp Method. 3. Bucket Method. Salt Dilution Method is mostly used in Micro Hydro. Head Measurement can be performed through the following measures: 1. Water filled tube 2. Sighting meters We measured the discharge using area velocity method and salt dilution method. Likewise, we measured the head using water filled tube and Abney levels. Area Velocity method This Method is based on the principle that for a fluid of constant density flowing through a cross-section, the product of cross-sectional area and mean velocity will be constant that is the discharge. Q(m3/s) = Area(m2)× vmean(m/s) The most practical method of measuring stream discharge is through the velocity-area method. This method involves measuring the velocity of a neutral buoyancy object (e.g., wood, plastic bottles etc.) and multiplying this by the average cross-sectional area (using a tape and rule) of the river gives the discharge of that stream. These objects do, however, float close to the river

surface, which is faster than the average velocity of the water profile and must, therefore, be reduced by a coefficient called correction factor (in our case we chose the value of correction factor as 0.75). Procedure: Person X stays at upstream and person Y stays at down-stream at some measured distance. Person X then puts a float at a fairly fast moving point in the river and lets it sweep. The time in the stop watch is noted down when the float travels the prefixed distance. The procedure is repeated 10 times with different floats. The distance travelled by the float divided by the time gives its surface velocity. This surface velocity is then multiplied by appropriate correction factor to find the mean velocity. Ten such mean velocities are calculated and mean is calculated. The mean cross sectional area of the river is found by finding the mean depth and multiplied it by the width of the river. The mean depth is found by measuring depth at all locations from one side of the channel to the other side of the channel and taking a mean. Observation table: Distance Time taken to travel this travelled, Si m distance, Ti sec. 20 17.5 20 23 20 19.2 20 18 20 19 20 17.1 20 17.96 20 19.17 20 17.76

Surface velocity Vi = Si/Ti m/s 1.1428 0.868 1.0416 1.1 1.0526 1.168 1.1 1.0432 1.1249

Correction factor ( C.F) = 0.75 So, mean velocity with correction factor = 0.8037 m/sec Area of cross section = mean depth of channel × width of the channel = 0.2514×1.35 = 0.3394 m2

Discharge (Q)

= Area of cross section × Mean velocity = 0.3394×0.8037 = 0.2727 m3/s = 272.77 l/s

Salt gulp method Salt Gulp method is easy to accomplish, reasonably accurate (error 23.96) Percentage oversize = 14 % (