Research On Equipment Maintenance Strategy Considering Power Grid Flexibility And Operational Risk

The equipment maintenance schedule plays a key role in the reliable operation of power system.With the increasing demand for the reliability of power supply and the development of equipment condition assessment technology,condition-based maintenance has been gradually replacing the routine maintenance and corrective maintenance,bringing greater economic and social benefits to the power grid.However,when making maintenance decisions,the departments focus on the individual status and maintenance cost of equipment,often ignoring the impact of maintenance schedule on the overall operation performance of power grid.Especially in recent years,UHV AC/DC interconnection and mass penetration of renewable energy has increased the difficulty of risk relevance modeling between power grid and equipment.Therefore,from the perspective of power grid flexibility and operational risk,the following studies are carried out in this paper to optimize the maintenance strategy formulation.Firstly,to promote the engineering application of risk-based maintenance decision,a weak link identification technique for power grid based on topology modeling and association set decomposition is proposed.The equivalent model of power grid topology is established via the analysis of CIM data,and the concept of Equipment Association Set is considered as the basic unit of risk assessment to improve the maintenance efficiency.Based on the equipment outage model,contingency screening strategy and optimal load-shedding model,the N-1 operational risk caused by the association set outage is evaluated,identifying the weak links and providing guidance for maintenance decision.The application case in actual power grid demonstrates the significance of the proposed technique to reduce the operational risk.Secondly,to improve the operational flexibility of power grid with wind power integrated,a method of maintenance and operation decision based on scenario analysis and collaborative optimization is proposed.The typical scenario set of wind power output is obtained via Latin hypercube sampling and K-medoids clustering method,and the target scenario set size is determined according to the typicality evaluation indices.With economy and flexibility as the goals,a maintenance-operation bilevel collaborative optimization model combined with multi-scenario economic dispatch is formulated.To improve the solution efficiency,an improved Benders decomposition method with light tolerance of power flow limit violation is proposed,which reduces the dimensions of constraint matrix in the main problem of operation optimization.Lagrangian relaxation technique and multiplier update mechanism help to coordinate the maintenance schedule and operation optimization.Cases of IEEE 6-bus and 118-bus show that the proposed method can effectively optimize the economy and flexibility of maintenance-operation decision.Finally,on the basis of the above research and the needs of actual power grid maintenance and dispatch departments,a risk management module for maintenance schedule based on equipment risk panoramic information is developed.The modeling and integration mechanism of equipment risk panoramic information is introduced,and the assessment and decision results solved by the module is displayed through the visual interface.The module has been applied in the dispatch departments of regional and provincial power grids,which ensures the security and economy of power grids in the process of maintenance implementation,achieves a closed-loop optimization of condition-based maintenance decision,and provides technical support for enhancing the depth and breadth of security risk prevention and control.