Abstract: A power system state estimation method based on set theoretic estimation model may be provided. In this method, all prior information of state estimation in a power system at least including a network topology and network parameters of the power system may be collected. A set theoretic estimation model for state estimation in the power system may be constructed by initializing original intervals of state variables and measurements and extending measurement constraints by algebraic manipulations to eliminate pessimism. Interval constraints propagation may be performed until the constraints to the state variables may be contracted. And resulting intervals of the state variables and measurements may be output.