Research On Topology Parameters Analysis And Cascading Failure Prevention Control For Complex Power Network

With the expansion of the scale of power system and the continuing growth of power load, people growing depend on safe and reliable electricity. Because of the limit of power system itself and the influence of external disturbance conditions, accidents occur frequently in electric power system. And large parts of the blackout accidents are developed by cascading failure. A cascading failure is often caused by a single component failure or a circuit overload. Components out of running in succession will cause blackouts in large area and even the collapse of the whole power grid. In the early stage of the development, the blackout can be completely avoided if a power operator controls properly.The topological structure of the power grid has its specific and internal characteristics, and the particular topological structure will have a profound influence on the performance of the grid. Therefore, this article analyzes topology parameters of the complex network in view of the topological structure of grid. The topology parameters of different cascading failure model in complex network are compared. Some topology parameters in complex network are given, which needs to be taken into consideration when the control of load shedding and generator tripping is taken to prevent the cascading failure. That can be a foundation for the prevention control of cascading failure.After the judgment of the circuit overload caused by flow transferring in the power system, a method that how to select the optimal nodes of load shedding and generator tripping control is given through the improved complex network topology parameters and the relationship between the node current and branch current. And then it is showed that how to calculate and select the appropriate controlled quantities of load shedding and generator tripping to prevent the cascading failure. It is showed that the current of overload line cannot reduce to a safe range after once control of load shedding and generator tripping through the simulation of IEEE30 nodes system. More steps of load shedding and generator tripping control need to be taken.In this thesis, a distributed optimization algorithm for model predictive control is used in the prevention control of cascading failure. The optimal solutions about the selected controlled quantities of load shedding and generator tripping are given through the dynamic matrix control algorithm. The optimal controlled quantities are applied to the actual power grid. Then the objective of the spread of cascading failure inhibited can be achieved through the real-time optimal control. Finally, the method of optimal control of load shedding and generator tripping is verified to be feasible through the simulation of IEEE30 nodes system.