| In recent years,with the rapid development of AC-DC and power grid interconnection projects,power system has developed from small-scale regional power grid to interconnected power grid with close connections and mutual coupling in China.The interconnection of regional power grids effectively solves the problem of uneven distribution of resources and improves the utilization of resources,but the formation of large-scale power system increases the risk of blackout.Because of the heterogeneity of the regional power grid and interaction between different regional power grids are not considered in the traditional simulation model of cascading failure,it has certain limitations in exploring the rules of blackout in interconnected power grid.Therefore,it plays an important role in ensuring the safe and stable operation of interconnected power grid to establish the model of interconnected power grid cascading failure,effectively evaluate the risk of interconnected power grid blackout and formulate control measures of interconnected power grid cascading failure.Firstly,based on the theory of cellular automata,a number of cellular automata models with regional characteristics according to the actual operation characteristics of interconnected power grid are constructed,and the heterogeneous cellular automata model is established by considering the interaction between different cellular automata models.The model is used to simulate the blackout of interconnected power grid and observe the blackout evolution laws of interconnected power grid in different operating states.By comparing the model with the cellular automata model,the advantages of the model are verified from the aspects of model characteristics,fractal dimension and simulation flow and time.Secondly,in order to effectively evaluate the blackout risk in interconnected power grid,a risk assessment method for interconnected power grid is given based on the generalized extremum theory,and regional grid blackout risk indicator is established to explore the change rules of blackout risk in different scenarios.Entropy weight method and analytic hierarchy process are used to identify the key cells by considering the risk value of regional power grid,power flow distribution,electrical betweenness and failure frequency.IEEE 118-bus stystem and HN power grid are taken as simulation examples,the simulation results verify the correctness of the risk assessment method and the key cells identification method.Finally,according to the characteristics of preventive-overload correction control and the coordination relationship among regional power grids in different cascading failure stages,the coordinated control measures for interconnected power grid are formulated.The heterogeneous cellular automata model is used to simulate the blackout of IEEE 118-bus system and HN power grid,the effectiveness and practicability of the control measures are verified from three aspects:the loss load sequence,the power flow distribution and the risk value of blackout. |
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