Abstract
To achieve topology optimization of the power grid and alleviate voltage constraints, a stage based optimization model for transmission line switching under N-1 safety constraints is proposed. Firstly, conduct a thorough analysis of the N-1 constraint, construct a multi-objective optimization configuration model with clear boundaries, and then use quantum genetic algorithm to solve the balance feasibility and economy. Based on the four stage model, evaluate and optimize the reliability of the transmission line, calculate the voltage changes at the over limit nodes, and introduce indicators to evaluate the effectiveness. The test shows that it has good performance, with a sensitivity of 0.21, low risk value, and strong load transfer ability.