Surge Impedance Loading level enhancement of 765 kV long EHV AC line through bundle configurations

The power capacity of transmission depends on two limits i.e. stability/SIL (Surge Impedance Loading) and thermal limits. For a long EHV AC line the power capacity of transmission is limited by Surge Impedance Loading limit due to the presence of large inductance of line. Decrease in inductance and surge impedance would increase SIL (Surge Impedance Loading) level. SIL depends on many factors such as spacing between conductors, bundle spacing, diameter of conductor, No. of sub-conductors per phase, conductor and sub-conductor configurations. In this paper for the particular data of 765 kV single and double circuit transmission line configuration the effect of bundle spacing and bundle configurations would be seen to improve power transmission capacity. The optimization of spacer and damper requirement is shown considering weight and cost of transmission. The result has been obtained using the mathematical programming in MATLAB software.