COMPARISON  OF AC AND DC TRANSMISSION: 

The  relative merits of the two modes of transmission (AC and DC )  which need to bee considered by a system planner are based on the following factors :

1. Economics of trans mission 
2. Technical performance 
3. Reliability.

      a major future of power systems is the continuous expansion necessitated by increasing power demand. This implies that the establishment of particular line must bee considered as a part of an overall long term system planning.