During my internship period at RMA (Pvt) Ltd, I was tasked to come up with a solution to predict the final overall cost at the design stage of a new transmission line, such that it will be possible to compare multiple transmission line options and choose the most optimum one. My supervisor for this research was Mr. Swetha Perera.
Listed above are the stages of transmission line design that is in current practice in Sri Lanka. During ‘Route Selection’ stage, suitable paths between beginning and end sites are drawn in Google Earth, and the shortest path which minimizes the number of affected properties is chosen. But the assumption that it also has to be the least cost incurring option since it needs less conductor and compensation is not always true.
Therefore I researched about all the explicit and implicit variables that affect the final cost of the transmission line, and determined how best to estimate them from the route selection stage. For this research, I took the case study of a planned 132kV transmission line between Katukenda and Mirigama.
I used ExcelVBA to develop a program where the transmission line path alternatives could be input with the determined variables and the proposed design. Using this design data, and other fixed and variable data such as monetary values the program then estimates the cost of all the alternatives, which would enable the user to select the most optimum route.
I presented the findings of the research and my developed program ‘Tx Design Cost Calculator’ at my final day of internship to everyone at the company, and it was very well received. I also wrote a user manual for anyone who intends to use that program or develop it
Sarangan Rajendran 