Power System Enhancement By Simultaneous Ac- Dc Power Transmission Case Study (Asella To Segure +15 Kv Transmission Line)

Abstract

Due to the increasing of power demand there are requirements for the construction of new transmission lines. But right of way problems are hindering the erection of transmission lines. In transmission line the power flow is much lower than its thermal limit due to the constraints related to stability. So instead of erecting new lines the existing AC lines are modified to simultaneous AC-DC lines to increase their power transfer capability and enhancing the transient stability close to their thermal limits. This study will give the feasibility of improved power transfer for Asella to Segure +15 kV power transmission by simultaneous AC-DC transmission and analysis the cause of power loss on transmission line. It is possible to convert existing AC transmission line into a simultaneous AC-DC power transmission line without the alterations of conductors, insulator strings and towers structure of original line by using only the converter at sending end and receiving end of transmission. The sending end side converter is used to convert the existing AC voltage into DC voltage and on the receiving end side there is other converter which is used to convert the converted DC voltage sent from sending end to AC voltage. In addition, with the two converter station in this study, four zigzag transformers are added to the system for converting pure AC line into simultaneous AC-DC line. MATLAB Simulink software is used for simulation purpose in the study. The study conducted the simulation analysis considering only transmission line, without including the whole system from generator to infinite bus. The simulation result shows the stability of power system for both existing system and the new system under no fault condition.