Weak Part Identification In Power Grid Based On Self-organized Criticality And Research On Control Measure

China has been working hard on construction of power grid and expansion of grid scale, since reform and opening-up, which may promote the efficient development in electric power industry and start a UHV AC/DC hybrid transmission which is large-scale,high-efficiency,long-distance. The large-scale interconnection of power grids has promoted the continues improvement in its capacity of resources allocation and economy. However, with the development of the global energy interconnection and the expansion of the scale of power grid, the dynamic behavior of the grid is becoming more complex and the fault probability is increasing constantly. Especially in recent years,a large number of power system blackouts occurred at home and abroad, which may sound the alarm for the stability of the power grid and cause wide attention of scholars. It can be seen from the evolution process of these blackouts, although they are different in performance forms, most of them started from a weak part, which caused multiple components failure because the control measures are not timely or properly. Therefore, it is significant to study the vulnerability of power grid, find out its weak parts and take method to defend them, in order to maintain the security and stability of the power grid.In this thesis, integrated index of weak line identification that considering loading rate distribution uniformity is proposed based on self-organized criticality.Using the dynamic behavior to judge the current running state of power grid. The effectiveness of the integrated index is tested using IEEE39-bus system. On the basis of the integrated index, the comprehensive index is derived by combing the risk entropy and Markov. The comprehensive weight is quantified by applying analytic hierarchy process (AHP). By simulating GS power grid, the results demonstrate that the comprehensive index can find weak lines well.In order to identify weak nodes in power grid, a comprehensive index identification method that considering loading rate distribution uniformity, system loading rate and load loss relative value is given in this thesis. Based on the IEEE 39-bus system and the GS power grid,the simulation results show that the comprehensive index can reflect the weakness of the nodes and it is closely with the actual operation of power grid.In the view of the real-time stability control of power grid, the corresponding control rules are established to determine the location and amount of load shedding,so as to avoid large-scale blackout caused by weak line faults. The feasibility of the proposed control scheme is verified by the simulation of the IEEE3 9-bus system, and it is applied to the security and stability control of the actual power grid.