POST TECHNICAL AND ECONOMICAL ANALYSIS 
OF A 132 KV TRANSMISSION SUB NETWORK OF 
CEYLON ELECTRICITY BOARD 
 
 
 
A dissertation submitted to the 
Department of Electrical Engineering, University of Moratuwa 
In partial fulfillment of the requirements for the 
Degree of Master of Engineering. 
 
 
 
By 
Jayasekera Mudalige Kanishka Jayasekera 
 
 
Supervised by: Professor J.R. Lucas 
 
 
Department of Electrical Engineering 
University of Moratuwa, Sri Lanka. 
 
2006 
 
86326 
 
 
 
  
Abstract 
 
Power transmission network components are planned and designed for 30 to 40 years 
operating period in the network after construction. From planning stage to 
construction stage it takes about four years. The horizon of the planning process of 
Ceylon Electricity Board is ten years and each year the planning process is reviewed. 
Therefore ideally once a transmission line is constructed and energized, it should 
serve the system requirements for 30 to 40 years. 
 
In a transmission network, grid substations and power stations are connected to each 
other. More number of grid substations are appeared in areas where industrially and 
commercially populated. The generated bulk power from major power stations are 
transferred to the heavily populated areas through grid substations. As the number of 
grid substations are increased in an area, power stations may also be added to the 
system with in the same area, to cater the demanded load maintaining the quality of 
supply. 
 
The cost of the transmission line construction is large and it varies according to the 
lengths of the line and the capacity. The optimal outcome of the combination of 
planning and designing of a transmission line is, at the energization, the line should 
be loaded minimum, the construction cost should be minimum and it should serve 
the system for full designed period maintaining the system security. 
 
An evaluation was done for the 132 kV transmission network connecting Kolonnawa 
GS, Kelaniya GS, Kotugoda GS, Sapugaskanda GS, Biyagama GS and Asia Power 
PS which was reconstructed recently. The evaluation was based on load flow studies 
and the cost of construction. The load flow studies were done using the software of 
Power System Simulator for Engineering. 
 
 
 
  
It is observed that mere reconstruction or upgrading the old system will not give the 
optimal solution in network expansion. With the addition of more and more grid 
substations to the system, re-arrangement of possible transmission network sections 
would result better and optimal network behaviour. 
DECLARATION 
The work submitted in this disse11ation is the result of my own investigation, except where 
otherwise stated. 
It has not already been accepted for any degree, and is also not being concurrently submitted 
for any other degree. 
~era 
12.01.2006 
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I endorse the declaration by the candidate. 
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Professor J.R. Lucas. 
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Declaration 
Abstract 
Acknowledgement 
List of Figures 
List ofTables 
List of principal symbols 
1. Introduction 
1.1 Background 
1.2 Motivation 
1.2 Scope 
2. Statement of the problem 
2.1 Preliminaries 
2.2 Problem identification 
2.2.1 A load flow analysis 
CONTENTS 
2.2.2 Present sub network operating system 
2.2.3 Recorded recent loads of sub network 
2.3 Analysis for a optimal network arrangement 
3. Analysis 
3. 1 Possible network configurations 
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3.1.1 Alternative 01- Old sub network in the transmission system 2005 
3.1.2 Alternative 02- Adding new line in between Sapugaskanda and Biyagama 
3.1.3 Alternative 03- Old lines in between Kolonnawa and Kotugoda 
3.1.4 Alternative 04- Old line in between Kolonnawa and Kelaniya 
3.1.5 Alternative 05- Old line in between Kelaniya and Kotugoda 
3.1.6 Alternative 06- No line in between Kolonnawa and Kelaniya 
3.1.7 Alternative 07- No line in between Kelaniya and Kotugoda 
3.1.8 Alternative 08- No lines in bet\\'een Kolonnawa and Kotugoda 
3.1.9 Alternative 09- Asia Power PS connecting to Sapugaskanda 
3.1.10 Alternative 10- Combination of Alternative 08 and Alternative 09 
3.2 Transmission line data and capacities of grid sQ~tation 
3.3 Tools of analysis 
3.4 Day peak and night loads 
3.5 Peak load analysis 
3.5. 1 Alternative 0 1- Old sub network in the transmission system 2{)05 
3.5.2 Al ternative 02- Adding new line in between Sapugaskanda and I1iyagama 
3.5.3 Alternative 03- Old lines in between Kolonnawa and Kotugoda 
3.5.4 Alternative 04- Old line in between Kolonnawa and Kel~ni)4i'> 
3.5.5 Alternative 05- Old line in between Kelaniya and Kotug6da 
3.5.6 Alternative 06- No line in bct,,een Kolonnawa and Kc'lani) a / 
3.5.7 Alternative 07- No line in between Kelaniya and Kotugoda 
3.5.8 Alternative 08- No lines in between Kolonnawa and Kotugoda 
3.5.9 Alternati\ c 09- Asia Power PS connecting to Sapugaskanda 
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3.5.1 0 Alternative I 0- Combination of Alternative 08 and Alternative 09 
3.6 Outcome of the analysis 
3 .6.1 Alternative 11- No line in between Sapugaskanda and Biyagama 
3.6.2 Alternative 12- Combination of Alternative 07 and Alternative 11 
3.6.3 Summary of the outcome 
3.7 Economical aspects 
3. 7.1 Construction costs 
3.7.1.1 Construction cost of the implemented system 
3.7.1.2 Construction cost of Alternative 06 
3. 7 .1.3 Construction cost of Alternative 08 
3.7.1.4 Construction cost of Alternative 10 
3.7.1.5 Construction cost of Alternative 11 
3.7.1.6 CLmstruction cost of Alternati\'e 12 
3.7.2 Summar: of construction cost 
3.7.3 Cost of energy loss 
4. Results 
5. Conclusion 
References 
Appendix A- Forecasted loads for year 2005. 
Appendix B -Construction cost over loss of energy 
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ACKNOWLEDGEMENT 
1 express my gratitude to Professor J.R. Lucas and Professor H.Y.R. Perera in the 
Department of Electrical Engineering, University of Moratuwa, Sri Lanka., for their 
guidance and encouragement. My thanks are due to the staff of Department of Electrical 
Engineering, University of Moratuwa., for their assistance to me during my post graduate 
studies in the University. 
I am also grateful to the chief engineer and other engineers of the Transmission Planning 
office and system control centre of Ce) Ion f-lectricity Board for providing me the data. 
information and allo\\'ing me to use the computer facilities with relevant soft\\'arc. 
Finally. I should thank my family for helping me in various ways in making 111) post 
graduate studies a success. 
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List of Figures 
Figure I. I .I 
Figure 1.1.2 
Figure 1.1.3 
Figure 2.2.1.1 
Figure 2.2.1.2 
Figure 2.2.2.1 
Figure 2.2.2.2 
Figure 3.5.1.1 
Figure 3.5.1.2 
Figure 3.5.1.3 
Figure 3.5.1.4 
Figure 3.5.2 
Figure 3.5.3 
Figure 3.5.4 
Figure 3 .5.5 .I 
Figure 3.5.5.2 
Figure 3.5.6.1 
Figure 3.5.6.2 
Figure 3.5.7.1 
Figure 3.5.7.2 
Figure 3.5.8.1 
Figure 3.5.8.2 
1-igure 3.5.9.1 
Figure 3.5.9.2 
Figure 3.5.1 0.1 
Figure 3.5.10.2 
Figure 3.6.1.1 
Figure 3 .6. I .2 
Figure 3.6.2.1 
Figure 3.6.2.2 
Location of the 132 kV transmission sub network in map of Sri Lanka 3 
Configuration of sub nct\\'ork before construction 4 
Configuration of sub network after construction 5 
Load flow diagramme of the ex.isting system in night peak. , 8 
Load flow diagramme of the existing system in day peak. 9 
Load flo" diagramme for the present operating pattern in night peak. II 
Load flow diagrammc for the present operating pattern in day peak. 12 
Load flO\\ diagramme for Alternative OJ in night peak. 22 
Load flo" diagramme for Alternative 0 I in night peak when" Asia 23 
Po\\er .. fails 
Load flo" diagram me for A lternati\e 0 I in night peak with Kclaniya 25 
GS 
Load flo,, diagram me for Alternative 0 I in day peak with Kelaniya GS 26 
Load flO\\ diagrammc for Alternative 02in nigl!¥peak. 28 
Load flow diagrammc fo1 Alternative 03in night peak. 29 
Load flow diagramme for Alternative 04in night peak. 31 
Load flow diagrammc for Alternative 05in night peak. 32 
Load flow diagramme for Alternative 05in day peak. 34 
Load flow diagramme for Alternative 06in night peak. 35 
Load flow diagramme for Alternative 06in day peak. 36 
Load flow diagramme for Alternative 07in night peak. 38 
Load flow diagramme for Alternative 07in day peak. 40 
Load flow diagrammc for Alternative 08in night peak. 41 
Load flow diagrammc fo1 Alternative 08in day peak. 42 
Load flow diagramme for Alternati'e 09in night peak. 44 
Load flow diagrammc for Alternative 09in day peak. 45 
Load flow diagram me for Alternative I 0 in night peak. 4 7 
Load flo" diagramme for Alternative 10 in day peak. 48 
Load flo\\ diagramme for Alternative II in night peak. 5 I 
Load flo\\ diagramme for Alternative II in day peak. 52 
Load flu,, diagramme for Alternati\e 12 in night peak. 5•1 
Load flow diagramme for Altcrnati\e 12 in day peak. 55 
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List of Tables 
Table 2.2.1.1 
Table 2.2.1.2 
Table 2.2.2.1 
Table 2.2.2.2 
Table 2.2.3 
Table 3.1.1 
Table 3.1.2 
Table 3.1.3 
Table 3.1.4 
Table 3.1.5 
Table 3 1.6 
Table 3. 1.7 
Table 3.1.8 
Table 3.1.9 
Table 3. 1.1 0 
Tabk 3.2 
Table3.4 I 
Table 3 4.2 
Table 3.4.3 
Table 3.4.4 
table 3.4.5 
"I able 3.4.6 
Table 3.5.1. 1 
Table 3.5.1.2 
Table 3.5.1.3 
Table 3.5.1.4 
Table 3.5.2 
Table 3 5.3 
Table 3.5.4 
Table 3 5.5.1 
Table 3.5.5.2 
Table 3 5.6.1 
Table 3.5.6.2 
Table 3 5.6.3 
!"able 3.5.7.1 
!"able 3.5.7.2 
!"able 3.5.8.1 
!"able 3 5.8 2 
!"able 3.5.8.3 
Table l 5.9.1 
Table 3 59 2 
rablc35.10.1 
rablt: 3.5.1 0.2 
rable 3.5.1 0.3 
Tabk 3.6.1 
Table 3.6.1.1 
rablc 3.6.1.2 
rable 3 6.1.3 
rable 3 6 2 I 
fable 3 6.2.2 
Table 3.6.2.3 
Table 3 6.3.1 
Table 3 6 3.2 
Table 3 ~.2.1 
Out come of the night peak load flow of the constructed transmission sub network. 
Out come of the day peak load flow of the transmission sub network. 
Out come of the night peak load flow of the sub network as it has been operated. 
Out come of the day peak load flow for the sub network as it is being operated. 
Recorded peak loads in the months of July and August 2005 
Network configuration of A ltcrnative 0 I 
Network configuration of Alternative 02 
Network configuration of Alternative 03 
Network configuration of Alternative 04 
Network configuration of Altemative 05 
Network configuration of Alternative 06 
Network configuration of Alternatrve 07 
Network configuration of Alternative 08 
Network configuration of Altemati\C 09 
Network configuration of Alternatr,·e 10 
Rated load:. of the conductors 
Demanded and delivered peak power m month of February 2005 
Demanded and delivered peak power in month of March 2005 
Demanded and delivered peak power in month of May 2005.f 
Demanded and delivered peak power in month of July 200) 
Demanded and de livered peak power in month of August 2005 
Day and night voltages at the peak in the months of July and August 2005 at the 
adjacent buses 
Outcome ot the load flow for Alternative 0 I in night peak 
Outcome ofthe load flow for Alternative 01 in night peak when the "Asia Power" 
PSis failed to deliver power. 
Outcome of the load flow for Alternative 0 I in night peak with Kelaniya GS 
Outcome ofthe load flow for Alternative 01 in day peak with Kelaniya GS 
Outcome of the load flow for Alternative 02 in night peak 
Outcome of the load flow for Alternative 03 in night peak 
Outcome of the load flo\\ for Alternative 04 in night peak 
Outcome olthe load flow for Alternative 05 in night peak 
Outcome of the load flow for Alternative 05 in da) peak 
Outcome of the load flow for Alternauve 06 in night peak 
Outcome of the load flow for Alternative 06 in day peak 
Voltages of adJacent buses at day and nrght peaks fo~ Alternative 06 
Outcome of the load flow for Alternative 07 m night peak 
Outcome of the load flow for Alternative 07 in day peak 
Outcome of the load flow for Alternative 08 in night peak 
Outcome ot the load flow for Altemative 08 in~ peaJ..: 
Voltages of adjacent buse~ at da} and night peak'!. for Alternati'e 08 
Outcome of the load OO\\ for Alternative 09 in night peak 
Outcome of the load Oo'' for Alternative 09 in day peak 
Outcome of the load Oow for Alternative 10 in night peak 
Outcome of the load flow for Alternative I 0 in day peak . ..-' 
Voltages of adjacent buses at day and night peaks for Alternative l 0 
Summar) of percentage of line loads 
Outcome ot the load flo,, lor Alterna'live 11 in night peak 
Outcome of the load flow for A lternatrve I 1 in day peak . • 
Vo ltages of adjacent bust:s at day and night peaks for Alternativt: t'r· 
Outcome of the load flow for Alternatr\t! 12 in night peaJ..: " 
Outcome of the load flow for A lternatl\ c 12 in day peak 
Voltages of adJacent buses Jt dJy and night peaks for Alternative 12 
Percentage of ma,unum line loads in each configuration 
Total system net\\ ork loss with each sub network configuration 
Comparison of construction costs 
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List of Principal Svmbols 
ACSR All Conductor Steel Reinforced 
AP Asia Power 
Biya Biyagama 
Capa Capacity 
Cct Circuit 
CEB Ceylon Electricity Board 
Cond. Conductor 
Condi. Condition 
Con. Constructed 
cc degree Centigrade 
0 /C Double Circuit 
GS Grid Substation 
Gen. Generated 
IPP Independent Power Producer 
Kela Kelaniya 
Kolo Kolonnawa 
Kotu Kotugoda 
N Number of circuits 
Ope. Operating 
PS Power Station 
PSS/E Power System Simulator for Engineering 
S/C Single Circuit 
Sapu Sapugaskanda 
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