Abstract—In recent years, environmental right-of-way and cost concerns have delayed the construction of a new transmission line, while demand of electric power has shown steady but geographically uneven growth. The wheeling of the available energy through existing long ac lines to load centers has a certain upper limit due to stability considerations. Thus, these lines cannot be loaded to their thermal limit to keep sufficient margin against transient instability. This paper presents the concept of composite ac-dc power transmission. The conductors are allowed to carry usual ac along with dc superimposed on it. This paper also presents the feasibility of small power tapping from composite ac-dc power transmission lines which would pass over relatively small communities/rural areas having no access to a major power transmission network. It is economical compared to complicated methods of tapping from the HVDC line. The proposed scheme is digitally simulated with the help of MATLAB software package. Simulation results clearly indicate that the tapping of a small amount of ac power from the composite ac-dc transmission line has a negligible impact on the normal functioning of the composite ac-dc power transmission system.

Index Terms—Extra High Voltage (EHV) transmission, Flexible AC Transmission System (FACTS), MATLAB simulation, simultaneous ac-dc transmission, small power tapping

Cite: K Shobha Rani and C N Arpitha, "POWER UPGRADATION AND POSSIBILITY OF SMALL POWER TAPPING FROM COMPOSITE ACDC TRANSMISSION SYSTEM," International Journal of Electrical and Electronic Engineering & Telecommunications, Vol. 2, No. 3, pp. 36-43 July 2013.