Evaluation Of New-form Urban Power Grids And Self-healing Of Transmission And Distribution Coordination

The stability and safety of the urban power grid is related to the daily life of ordinary people.The failure of the urban main network often leads to large-scale blackouts.As the terminal network,the distribution network may be a victim of network security and stability.With the continuous access to renewable energy,the flexibility of the distribution network is gradually improving.It can provide more options for the security and stability of the main network.In the traditional sense,the gap between the main network and the distribution network is becoming blurred.The one-size-fits-all equivalent method of side-pair distribution network is obviously no longer suitable for new development trends.In order to better coordinate the operation of the main network and the distribution network,the main-distribution coordination model came into being.Through the unified modeling of the main network and the distribution network,the main network and the distribution network form a complete network in the topological structure,which is a prerequisite for the coordination of the main network.In the main distribution coordination mode,the distribution network is no longer the equivalent load on the main network side,but a specific network with a topology structure.Its participation makes the action plan of the main network more flexible when a failure occurs.Compared with the previous case where the main network and the distribution network are split,the loss of load is less,and the load supply capacity of the entire system is effectively improved.This paper analyzes the key technologies of the master-distribution collaboration model,and applies the graph theory-based network reconstruction method to the master-distribution collaboration model.At the same time,the method is improved for the large number of Y-shaped structures and their composite structures in the network,making the method more effective It can quickly eliminate infeasible solutions when dealing with the network reconfiguration problem of the master-distribution coordination,and improve the efficiency of the generation scheme.The network reconstruction in the transmission and distribution coordination mode aims to restore the power supply of the lost equipment as much as possible to the urban power grid,reduce the load loss caused by the accident,and improve the operation state of the urban power grid after the accident.It is a necessary way to restore the operation state of the urban power grid.Then,based on the existing research,a complete comprehensive evaluation system for the operation status of urban power grids was constructed,which improved the current system’s insufficient representation of the self-healing level of urban power grids,and combined the fuzzy expert scoring method and related images based on reflection.The matrix method screens the established index system,and trades less information loss for better information overlap,which makes the evaluation process more concise and avoids unnecessary recalculation.Use the established index system to comprehensively evaluate a certain city’s power grid.Select the improved AHP and CRITIC methods to set subjective and objective weights respectively,and set the comprehensive weights through the principle of minimum discriminative information;use the improved approach to ideal solution ranking method for comprehensive evaluation,and on the basis of which the method cannot determine the evaluation results of the underlying indicators The problem is improved,and the evaluation results of the underlying indicators are obtained through the shrinkage of the relative closeness in one-dimensional space,so that decision-makers can more comprehensively control the operation status of the urban power grid,and have a clearer understanding of the weak links of the power grid.The upgrade and improvement of the power grid can also help decision-makers to make better decisions about the current situation.The results show that the improved network reconstruction method based on graph theory in this paper can well adapt to the master-distribution collaborative network,and effectively solve the obstacles caused by the Y-shaped structure and its composite structure;the index combination screening method can take into account subjective experience and objective data.,Less loss of information,not only reduces the information overlap of the index system,but also ensures the completeness and comprehensiveness of the index;the improved approach to ideal solution sorting method is more abundant in the evaluation results,and will not change the original sorting and decision-making People can make decisions with more information.