Abstract:
Simultaneous AC-DC power transmission technique can improve both
loadability and stability of a power system with long transmission line. But,
there is a tradeoff between loadability and stability, i.e. increase in the
improvement of loadability causes the decrease in the improvement of
stability and vice versa. Actually, it is a multi-objective optimization problem
where the objective function depends on two decision variables with opposite
in nature. Firstly, this paper presents an analytical expression for the
objective function which is the function of two decision variables; power
flowing capacity and critical clearing time. Secondly, a mathematical model
is developed for the optimal point of the objective function. Considering a
typical system a numerical analysis is performed using the proposed
expressions. Again, the impacts of the line length and the voltage level of a
transmission line on the objective function are also investigated. Finally, the
developed model of the optimal point is validated to judge its accuracy and
applied to a real system to justify its ability to evaluate the combined benefit
of loadability and stability of simultaneous AC-DC system.
