  Optimized operation of the transmission network is one solution to supply
extra demand by more efficient use of transmission facilities, and line
switching is one main tool to achieve this goal. In this paper, we add extra
constraints to OPF formulation to limit the maximum number of switching
operations in every hour based on network conditions, and add switching cost in
the objective function to represent extra maintenance cost as a result of
frequent switching. We also propose an algorithm to remove less important lines
for switching in different loading conditions, so OPF with transmission
switching will be solved faster for real-time operation. It is applied to a
case study with several operation hours.
