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Title: “Design of Power Evacuation system in Western part of INPS”
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Project description Nepal is divided into five development regions, 14 zones and 75 districts. Western development region is one of the development regions which comprises of three zones, Lumbini, Dhaulagiri and Gandaki and has 16 districts. This project will study the present and will identify future power evacuation system and mechanism in certain area of Syanja, Palpa, Arghakhanchi, Pyuthan, Gulmi, Rupendehi districts from different existing, under construction and upcoming power plants (Jhimruk 12 MW, Andhi Khola 5.1 MW existing; Khudi 3.5 MW under construction; Jhumdi 2 MW upcoming hydro power plants). The project will study existing and proposed power evacuation system and will carry out detail analysis of an existing transmission infrastructure for upgrading and will also conduct detail design of one of the selected power evacuation systems. The project shall also focus to upgrade the selected existing distribution system. The main scope of the works under this project is as follows: • Collection of data regarding existing and proposed electrical system in the study area through walkover survey. • Preparation of program/software for technical and financial analysis of evacuatio n system( includes: transmission line, substation and distribution system) • Identification of different transmission line alternatives and selection of best option. • Detail design of one evacuation system. • Design of substation and upgrade distribution system. This project will be supervised by Mr. Surya Prasad Adhikari, Planning and Design Engineer, Butwal Power Company and Mr. Lalit B Rana, Asst. Prof. Kathmandu . University.
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Background: In addition to government owned power development agencies (like NEA, MOW, WECS, and EDD) the private power development agency, Butwal Power Copmany is also actively participating in Generation, Transmission and Distribution of electrical power to INPS as well as local consumers. Butwal Power Company Limited (BPC) is the first private sector Power Company of Nepal. Today BPC is a leading Hydropower developer of the country. This project will be carried out in collaboration with BPC. Generally the hydropower projects are located at remote place and power cannot be consumed in the periphery of the project site. So in order to evacuate power from hydropower plant to load centers transmission line is needed. As the load is
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growing rapidly and there is a scarce of power source most of the power developers are giving attention to add new power plants to meet future demand. In case of BPC, Khudi power plant 3.5 MW is under construction and Jhumdi 2 MW power plant is under study. So it is clear that a lot of study is going on for identification of new power generating sites but no prudent method for evacuating power generated from new upcoming generating plants have been studied. Upgrading existing power evacuating system is needed to reduce tripping and increase generation as well as reduce losses. This project will study the exis ting transmission mechanism in the area where BPC is involved in Generating, Transmitting and Distributing electricity. This project will work out for the optimum use of existing transmission system and identified proposed power evacuation system. From field visit all the information and data regarding existing as well as upcoming transmission mechanism will be collected and among the selected transmission systems this project will carry out detail design of one evacuation system. For the identification of a project walk over survey is chosen in the study area. The walkover survey will include visiting of existing power plants like Jhimruk, Andhi Khola; under construction power plant Khudi and upcoming power plant Jhumdi. In addition to power sending substation (Primary Substation) in power plants, sites at existing and proposed power receiving substation (secondary substation) will be visited and all the data required for designing evacuation system will be collected. Alternate transmission line route, lengt h of transmission line, turning points, sag, will have to be considered while designing and the information on these will be extracted from either Topographic Map or digitized map (if available). For designing power evacuation system following parameters are considered: o Determination of Transmission capacity o Available Transmission margin o Transmission and distribution system Planning Transmission Capacity Transmission Capacity is the maximum power that can be delivered from power generating station to the distribution station and depends on line length, size of conductors and voltage level. In case of existing evacuation system the project will make analysis for the optimum use of the available system taking into account of load growth factor and other site specific parameters like type of consumers and future power demand. While determining transmission capacity of new transmission system, load growth of the power consumption area, possibility of addition of new power plants are to be considered. The project will be chosen as required while designing a power evacuation system for a selected site. Available Transmission Margin Available transmission margin is the maximum allowable power that can be transmitted without tripping the control and protection equipment used in primary
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and secondary distribution substation. In many existing evacuation system transmission capacity is limited by available transmission margin and this project will identify the available transmission margin and suggest technical improvement to increase the transmission margin up to transmission capacity of the visited existing system. Transmission and distribution system planning The project will focus on the present distribution system and will work out for future distribution planning which is the most important parameter required for designing power evacuation system. Transmission and distribution planning is done so that present and future power required by local consumer is identified and help in designing required evacuation system. Distribution planning will be done using load forecasting of study area which includes study of load growth pattern, load flow analysis and economic analysis. 4. Goal and Objective This project will be carried out as per requirement for designing power evacuation system needed by BPC or other power developer in case of upgrading existing hydro plants, upcoming hydropower plants and possibility for the future addition of proposed hydro plants. The project should be able to analyze existing as well as proposed distribution system to determine present and future load demand. Finally the project should be able to design power evacuation system and able to perform financial analysis so that best option could be chosen. From this project concerned power developer like BPC will get analysis tool or methodology for designing cost effective well planned trans mission and distribution system and help in selection of best power evacuation system from different available alternatives with respect to both technical as well as managerial perspective. 5. Methodology The methodology presented for this project covers the approach that will be taken for collection of data, field survey, detail engineering design including project cost estimation and system analysis of proposed evacuation system including transmission line and substation. Methodology adopted for data collection will be from walk over survey, topographic map, digitized map and information regarding present and proposed electrical system from different organizations. This project will mainly focus on data acquisition on status of the existing primary distribution substation, status of the existing, upcoming and proposed plant and their respective power evacuation mechanism.
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Transmission line is needed to evacuate power from power plant to either NEA owned INPS or distribute locally. Therefore the project requires finding out possible alternative for construction of transmission line. Developing a program in MS Excel for carrying out technical and financial analysis of transmission line is the part of the project. For technical analysis electrical as well as mechanical design parameter will be used and for financial analysis project quantity and cost estimation will be used. Methods for designing transmission line consists of selection of taping point from primary substation or existing substation; selection of routing of transmission line; selection of conductor satisfying the technical requirements; selection of suitable pole and span for the line. The various alternative combinations of tapping points, routing and conductor selection will be investigated and best will be chosen considering following: • • • • • • • • • • Physical situation in probable source (either power plant or existing substation). Impact on existing system equipment within the limit. Minimizing length of line. Maintaining the voltage profile and line loss in the proposed and existing transmission line within standard limit. Minimizing overall investment and running cost. Opportunity for feeder expansion The cost of preparing the site (slope, drainage, underlying soil & rock) Cost of transporting material. Esthetic requirements Available options for expanding the substation capacities, addition of distribution feeder and extension of sub transmission line for the new substation that may come in future. The size of substation is highly dependent on the load growth.
The methods that will be adopted while locating of the substation are:
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The capacity of substation depends on the load growth of the area and 15 year peak load from load forecast of different type of consumers in the area will be considered to determine the size of the substation. The load forecast analysis require following information regarding • • • Type of customer, their socio-economic status and the numbers in the service area. The estimated average demand for different types of customer class. Annual load growth factor for different types of customer.
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• • • 6. Tools:
The projected electrification ratio for each costumer by 15th year. The load patterns, internal diversity factor and power factor from NEA's experience. Distribution loss from load flow analysis.
The project requires different software like MS Excel, Vbasic, Netbas, Matlab, and AutoCAD. All technical and financial analysis program will be deve loped in MS Excel. Visual Basic will be used to carry out load flow study of radial distribution network. For carrying out load flow analysis of transmission line alternatives Netbas will be used. Matlab may be used for engineering design calculation of transmission line and finally the project needs Auto Cad in order to map out different transmission line alternative and study available electrical system of the study area. 7. Work Plan: The work plan of the project is presented in Appendix A. This work plan is prepared in MS Project. The project will start from 11th July 2005 and ends at 10th Dec 2005. The milestones are fixed different important activities. The sequence of work and interdependence of activities are shown in Gantt chart in Appendix A. This project shall start with literature search from BPC and other power developer and after having enough information on present evacuation system and power plants (existing and proposed), field visit will be carried out in selected sites. After having all data required for design, software preferably in MS Excel will be prepared for technical as well as economic / financial analysis. Using software design of one of the selected proposed and existing evacuation as well as distribution systems will be carried out in detail. Finally, preparation and submission of draft report to external and local supervisor followed by final documentation and presentation. The work plan consists of following: 1. Literature search. 2. Field visit. 3. Software preparation. 4. Upgrading of selected existing evacuation system for its optimum use. 5. Design of selected proposed evacuation system. 6. Upgrading existing distribution system 7. Preparation of draft report. 8. Final documentation and presentation.
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