e TECHNICAL PRE-FEASIBILITY FOR DEVELOPING A TRANSMISSION SYSTEM INTERCONNECTION BETWEEN INDIA AND SRI LANKA - A CASE STUDY FOR MADURAI - VEYANGODA INTERCONNECTION A dissertation submitted to the Department of Electrical Engineering, University of Moratuwa in partial fulfillment of the requirements for the degree of Master of Science by LIBRARY UNIVERSITY OF MORATUWA, SRI LANKA MORATUWA S. W. A. D. N. WICKRAMASINGHE Supervised by: Prof. J. R. Lucas University of Moratuwa 92427 Department of Electrical Engineering University of Moratuwa, Sri Lanka / o V | ft 1 . 3 QCj toi TV February 2009 G 2 4 2 7 Declaration The work submitted in this dissertation is the result of my own investigation, except where otherwise stated. It has not already been accepted for any degree, and it also not being concurrently submitted for any other degree. S.W.A.D.N. Wickramasinghe Date: '3.. r.^. .7.?^f*. We/I endorse the declaration by the candidate. Prof. J.R. Lucas S.W.A.D.N. Wick ran tasing he M.Sc. in Electrical Engineering Hi Contents Declaration i Contents ii Abstract iv Acknowledgement v List of Figures vi List of Tables vii List of Tables vii List of Annexes viii 1.0 Background and Scope 1 1.1 Introduction 1 1.2 Background 1 1.3 Objective 2 1.4 Methodology 2 2.0 Analyzing of the present power systems 3 2.1 Present Indian power system 3 2.2 Present Sri Lankan power system 7 2.3 India - Sri Lanka Interconnection 13 3.0 Selecting the most suitable power transmission method 15 3.1 Capacity of the connection 15 3.2 Connection across the Sea 16 3.3 Transmission Technologies 17 3.4 Voltage of the connection 25 S.W.A.D.N. Wick ran tasing he M.Sc. in Electrical Engineering Hi 4.0 Selecting the most suitable location based on load forecast 27 4.1 Suitable locations in Sri Lanka 27 5.0 Transmission system analysis for the interconnection 31 5.1 Assumptions for the analysis 32 5.2 Transmission system analysis for the interconnection of 500MW to Veyangoda grid substation 33 5.2.1 Normal operating conditions 33 5.2.2 Single contingency operating conditions 34 5.2.3 Transmission Losses 35 5.3 Transmission system analysis for the interconnection of 500MW to New Anuradhapura grid substation 35 5.3.1 Normal operating conditions 35 5.3.2 Single contingency operating conditions 36 5.3.3 Transmission Losses 37 5.4 Evaluation of the Results 37 5.5 Interconnection Routes 39 6.0 Conclusion and Recommendations 41 6.1 Conclusion 41 6.2 Recommendations 43 References 44 Annexes 45 S.W.A.D.N. Wick ran tasing he M.Sc. in Electrical Engineering Hi Abstract To cater to the growing demand of power in Sri Lanka, establishing a power transmission interconnection between India and Sri Lanka has become very important at present. The objective of this study is to do a technically pre-feasibility analysis of such an interconnection with the power system in 2008 and to propose a new interconnection option for the transmission of power. Capability of the power transmission and the capacity of the link are decided by analyzing the present and future generation capacity in both countries. The locations for the potential terminus points for the interconnection are decided by examining the transmission systems. The most suitable power transmission method is selected by considering the technical and economic aspects. Finally the power transmission system of Sri Lanka is modeled with the selected interconnections and the power flow studies are carried out to analyze the performance of the system and to find the most suitable interconnection. According to the present and future generation and transmission capacity in both countries there is enough opportunity to justify a transmission interconnection between India and Sri Lanka. The capacity of the link has been decided for 500MW in short term and for 1000MW in medium term. Since there are many advantages of using HVDC over HVAC, HVDC technology has been chosen and for the reliability the bipolar configuration was selected. And the selected voltage was HVDC 400kV. As for the forecasted loads of the grid substations and the locations (nearness to the major load centers) of them Veyangoda grid substation was taken as the terminus point for the power interconnection in Sri Lanka. The decided route for the interconnection is via Mannar. Transmission system analyses were done for two cases as 500MW connected to Veyangoda and to New Anuradhapura. The observed low voltages at 220kV AC busses in both cases highlighted the requirement of reactive power addition to the system. The results of the studies confirmed that the transmission system around New Anuradhapura is fairly weak compared to the transmission system around Veyangoda. Also the losses of the system were high in New Anuradhapura case. Therefore Veyangoda grid substation was selected as the terminus point of the India - Sri Lanka power interconnection. S.W.A.D.N. Wickrarnasinghe M.St / , in Electrical Engineering VI11 Acknowledgement First and foremost I offer my sincerest gratitude to my supervisor, Professor Rohan Lucas, who has supported me by stimulating suggestions and encouraging throughout my thesis with his patience and knowledge. Also my thanks should go to Dr. J. P. Karunadasa, Head of the Department of Electrical Engineering, and the other members of the academic staff of the Department of Electrical Engineering, for their valuable suggestions and comments. In addition I would like to thank the officers in Post Graduate Office of the Faculty of Engineering of University of Moratuwa for helping in various ways to clarify the things related to my academic works in time with excellent cooperation and guidance. Sincere gratitude is also extended to the people who serve in the Department of Electrical Engineering office. Especially I must be thankful very much to my colleagues in the Transmission Planning branch of Ceylon Electricity Board for providing assistance in numerous ways to carry out the studies of the project. I express my thanks and appreciation to my family for their understanding, motivation and patience. Lastly, but in no sense the least, I am thankful to all colleagues and friends for giving their fullest co-operation throughout the time of research and writing of this thesis. S. W.A.D.N. Wickramasiiighc Aj.Si. in Electrical Engineering fUj LIBRA- CSA List of Figures Figure 3. 1: Cost breakdown for HVAC & HVDC !... 22 Figure 4. 1: Transmission system of Sri Lanka by 2011 28 Figure 5. 2: Line routes for the Madurai - Veyangoda interconnection 40 S.W.A.D.N. Wickrarnasinghe M.St/, in Electrical Engineering VI11 List of Tables Table 2. 1: Region-wise installed capacity for different fuel based generation in India..4 Table 2. 2: Region-wise peak demand in India 4 Table 2. 3: Inter-regional capacity of the transmission lines in India 5 Table 2. 4: The power situation of India from April 2007 to March 2008 5 Table 2. 5: Future power supply scenario of India for 2001-12 condition 6 Table 2. 6: Future capacity of interregional links by 2011-12 6 Table 2. 7: The distribution of generation capacity 7 Table 2. 8: List of future power plants up to 2015 8 Table 2. 9: Power demand at generation end from 2006 to 2026 10 Table 4. 1: Grid Substation Peak Demand Forecast from 2006 to 2015 29 Table 5. 1: Allowable voltage variations 31 Table 5. 2: Voltage criteria violations at 132kV & 220kV level for Veyangoda interconnection 33 Table 5 .3 : Voltage criteria violations in single contingency for Veyangoda interconnection 34 Table 5. 4: Voltage criteria violations at -132kV & 220kV level for New Anuradhapura interconnection 35 Table 5 .5 : Voltage criteria violations in single contingency for New Anuradhapura interconnection 36 S. W.A.D.N. Wickraniasinglie M.Sc. in Electrical Engineering vii List of Annexes Annex A - 1: Single line diagram of the Sri Lankan transmission system in year 2011 with 500 MW additions to Veyangoda grid substation 46 Annex A - 2: Load flow diagram for night peak thermal maximum condition - Veyangoda 47 Annex A - 3: Load flow diagram for night peak hydro maximum condition - Veyangoda 48 Annex A - 4: The load flow diagrams for night peak thermal maximum condition with the addition of capacitor banks to the system - Veyangoda 49 Annex A - 5: The load flow diagrams for night peak hydro maximum condition with the addition of capacitor banks to the system - Veyangoda 50 Annex A - 6: Single line diagram of the Sri Lankan transmission system in year 2011 with 500 MW additions to New Anuradhapura grid substation 51 Annex A - 7: Load flow diagram for night peak thermal maximum condition - New Anuradhapura 52 Annex A - 8: Load flow diagram for night peak hydro maximum condition - New Anuradhapura 53 Annex A - 9: The load flow diagrams for night peak thermal maximum condition with the addition of capacitor banks to the system - New Anuradhapura 54 Annex A - 10: The load flow diagrams for night peak hydro maximum condition with the addition of capacitor banks to the system - New Anuradhapura 55 S.W.A.D.N. Wickrarnasinghe M.St/, in Electrical Engineering VI11