Ultra-high speed fault clearing in transmission lines is a topic that has been developing for many years. The main objective for this work is to show improve of stability of the power system and show the economic benefits through an economic dispatch that is achieved through the increase of the maximum power transfer capacity in the transmission lines, that is, it increases the capacity limit for stability in transmission lines through ultra-high speed fault clearing. For the simulation was used an electrical system as an example implemented in the software DIgSILENT and MATLAB with different events and fault clearing times from 2 cycles to 6 cycles that will compare ultra-high speed fault clearing and conventional fault clearing. These benefits allows improving the economic dispatch.