To the problem of small induction motor that supplied by Variable frequency power temperature rise, according to the basic theory of heat transfer and using finite element analysis software, in the paper, it established a motor of two-dimensional transient temperature field model ,though the equivalent simplify of the structure and thermal conductivity, and the compare between the simulation of finite element software studies and the temperature experimental tests , It confirms the affect that variable frequency power on the motor temperature rise, and finds a simplified simulation of motor temperature field and parameters equivalent approach which do provide effective help to the design and use of the induction motor.

Due to wind resources distribution characteristics and current situation of power grid, wind power is mainly large-scaled and centralized developed in China. In order to meet the security requirements of power system under this circumstance, a real-time security constrained dispatch method considering the impact of wind power uncertainty on N-1 line contingency safety is proposed. Key N-1 line contingency security constraints are identified by sensitivity analysis and added into dispatching model. Robust optimization approach is employed to solve this optimal problem. Simulation results of the IEEE-30 nodes power system validated the rationality and feasibility of the proposed method.