With the development of power grid's scale

because of the increase of variables and huge dimensions

it will be increasingly difficult to solve the economic dispatch problem. In order to overcome the difficulty

the Benders decomposition method is used to decompose the security constrained economic dispatch problem into the main optimization problem without security constraints and the subordinate power flow problem with security constraints. The security constraints on the sub-problem are returned to the main problem by model reconstruction. And the original problem can be solved through coordination between main problem and sub-problem. In the process of solving the optimization problem

the adjusted values of units are distinguished according to current operation information. The units with small safety and economic contributions are centrally addressed. At the same time

the optimization time intervals are tested according to the physical characteristics of power flow and load change on the important section

and the unimportant neighbouring time intervals are simplified and combined. Then the number of unit variables and time intervals can be reduced

so as to lower the goal of solving dimensions. Finally

the results show that the proposed optimization method can greatly reduce the optimization time while retaining a high precision required by engineering calculation.