Redefining right-of-way width of 33kV tower line by minimizing disturbances to the vegetation

Abstract

With the economic development in the country the demand for electricity is becoming important so that the government needs to achieve 100% electrification in the country in near future. Here, providing a safe & reliable power supply to all sectors in the country has become a great challenge to the utility company. To cater this requirement, planning branches of Ceylon Electricity Board (CEB) do preliminary studies of new power lines, reliability evaluations, load flow studies, etc. Thereafter, medium voltage line is designed including the line length, current rating, circuit type (Four circuit/Double Circuit/Single Circuit), conductor parameters, staring & end points, etc. As the first step of this research study, a survey was done regarding the available line design techniques, design criteriae, details of the selected tower line, valuation methods of vegetation, conductor types used in tower line applications, right-of-way width of a transmission line, etc. The prime concern was drawn in collecting as much as possible data on vegetation distribution along the line, payment made on vegetation clearing, classification of trees, tree related information, locations of removed trees of the selected line, available structure types, most recent structure costs, foundation costs and erection costs, etc. With the rapid urbanization, finding a route for a new transmission line across a populated area is a major difficulty to be faced by the utility. In this study, width of a 33kV transmission line Right-Of-Way (ROW) is proposed. Internationally used vegetation management techniques for transmission line was studied, since a well-defined, eco-friendly methodology for vegetation compensation process has not been adhered to the conventional practice. Most of the countries in the world pay much attention in the construction of eco-friendly overhead power lines. Hence, application on Covered Conductors on 33kV transmission line construction in CEB was studied while ensuring the adoptability of newly developed CC in Sri Lanka. The existing line was re-designed using the LYNX equivalent covered conductor. The ROW widths and the per km cost of a 33kV tower line were calculated for three different cases considering the different equivalent spans. Considerable amount of cost could be saved by the utility while concerning the designed equivalent span and the conductor type for properly maintaining the ROW width.