Browsing by Author "Dissanayake, DMAK"

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item: Thesis-Full-text
Techno economic analysis on the use of fully insulated cable for 33kv overhead power distribution system in Sri Lanka
Dissanayake, DMAK; Hemapala, KTMU; Weerasooriya, K
Electricity Supply has become a fundamental commodity of present society. Hence, the availability and the reliability of the electricity distribution system have gained an utmost concern. Currently, Sri Lankan electricity distribution system of all over the island other than Colombo and Kandy Cities are networked through the 33kV Bare Overhead (BOH) lines. Ceylon Electricity Board (CEB) is being rapidly expanded 33 kV distribution network to cater rural electrification demands and the urban development demands. 33kV network has been constructed with poles and towers, many 33 kV lines pass through jungles and thick vegetation and further expose to the sea and lightning prone areas. Therefore, nowadays the utility has to face some critical issues along with existing distribution system, especially higher number of feeder tripping during the rainy seasons due to thick vegetation. Even with the new regulations and demands, lines are unable to maintain right-of-way with required safety clearance especially in urban areas. Thus, in my dissertation discussed the 33kV Aerial Bundled Cable (MVABC) system as a more economical alternative to Medium Voltage Bare Overhead (MVBOH) lines. Further, address how to mitigate certain operational, climatic and environmental issues with MVABC. It is presented a comparative economic analysis of MVABC with MVBOH and MVUG systems. The analysis takes into consideration the initial investment costs, net present value (NPV) of operational and maintenance costs and NPV of unserved energy of lines along with their specific lifetime period. Further, an algorithm has been developed that can be used all over the country to make decision for MVABC adaptation on feeders. Finally, a Software Tool is developed to make easy to generate decision for the same and review each case by doing the Sensitivity Analysis. The dissertation concludes with few recommendations, technical issues associated with MVABC can be mitigated by purchasing cables according to the finalized specification. Use of MVABC shall improve availability and the reliability of consumers’ power supply wherever the decision generated by mathematical model is yes.
item: Conference-Full-text
Ventilation of underground workings and improvement of comfort levels
(Department of Earth Resources Engineering, 2009-05) Hewage, SC; Rajapakse, RAAC; Rathnayake, RMD; Prasanna, EAP; Dissanayake, DMAK; Dharmaratne, PGR; Welideniya, HS; Rohitha, LPS; Karunaratne, S
Ventilation of underground mines is required to dilute and hazardous gases, control heat and provide oxygen for workers and machinery. Kahatagaha- Kolongaha mines, Dodamgaslanda was selected for the present study as it was remove restarted recently and therefore very little research has been done on air quantity and quality of the mine. The objectives of this research are to make a proposal to rectify the existing ventilation system and to upgrade the existing airflow system with modifications to the present system. A detailed ventilation survey was carried out by measuring the variations of airflow, pressure drop and humidity differences along four levels of the mine (i.e. 565ft, 805ft, and 965ft and 1132ft levels) and compared with the corresponding standard values which describe the permissible conditions to be met for working underground. The distributions of airflows, pressures and humidity in each level could be detailed on graphs and the areas where the additional air supplies were identified. It was proposed to install a dehumidifier to reduce the humidity level inside the mine. Suggestions were made to improve the present ventilation system by locating two booster fans in level 565 ft and 805 ft, which will enhance mine air quality increasing health and safety aspects of underground environment.
item: Conference-Full-text
Ventilation of underground workings and improvement of comfort levels
(2014-08-08) Hewage, SC; Rajapakse, RAAC; Rathnayake, RMD; Prasanna, EAP; Dissanayake, DMAK; Dharmaratne, PGR; Welideniya, HS; Rohitha, LPS
Ventilation of underground mines is required to dilute and remove hazardous gases, control heat and provide oxygen for workers and machinery. Kahatagaha- Kolongaha mines, Dodamgaslanda was selected for the present study as it was restarted recently and therefore very little research has been done on air quantity and quality of the mine. The objectives of this research are to make a proposal to rectify the existing ventilation system and to upgrade the existing airflow system with modifications to the present system. A detailed ventilation survey was carried out by measuring the variations of airflow, pressure drop and humidity differences along four levels of the mine (i.e. 565ft, 805ft, and 965ft and 1132ft levels) and compared with the corresponding standard values which describe the permissible conditions to be met for working underground. The distributions of airflows, pressures and humidity in each level could be detailed on graphs and the areas where the additional air supplies were identified. It was proposed to install a dehumidifier to reduce the humidity level inside the mine. Suggestions were made to improve the present ventilation system by locating two booster fans in level 565 ft and 805 ft, which will enhance mine air quality increasing health and safety aspects of underground environment.