Research On Power Flow Transfer Problem Caused By Switch Off

With the execution of stratery that is called"power transmitting from west to east, power exchanging between north and south", large-scale grid is emerging; With the continuous development of industrial processe, the transmitted power is increasing day by day, operation at full load also is becoming common. It brought the huge losses to people's production and life. A lot of analysis show that protection misperation caused by flow transferring plays a key role in causing cascading trips, even the catastrophic blackout. Accident early is the best period of the accident's control, flow transfers in transmission section, total amount is small. Otherwise, total amount is large, at the some time, system instability may be accompanied, control system is difficult. As a result, resesrching rule of flow Transferring, plays a key role in effectively control system status and prevent deterioration of power system.In this paper, we further research the problem of the flow transferring caused by the cut line. By analyzing the general rule of the flow transferring, this paper proposes a kind of method that associates algebra with graph, which fastly identifies the flow transferring in power system with dynamic topology. This method firstly establishes corresponding matrixes according to the real-time network topology , predicts the scope of the influence of the outrages of over-load lines, and then, with the dynamic analytical method of power flow, analysing the key transmission sections which suffered greatly, judging the running state of lines. It can be applied to connected networks and unconnected networks, enrich the power flow transfer theory system. This method lays a reliable and solid foundation for real time safety analysing in power system.On this basis, we research the overloaded line. This paper proposes control strategy for load shedding and generator tripping, which contains comprehensive sensitivity analysis and optimization method, determining control node and control quantum and quickly reducing the power of the overloaded line. To achieve the safe and stable operation of the power of grid, prevent chain tripped events, or even blackout events laid a solid foundation. A large number of simulation experiments show the effectiveness of the proposed methods.