Research On Online Setting Method Of Backup Protection In Complex Ring Network

With the steady development of China’s national economy,the demand and consumption of electric power resources are increasing,which brings about a huge scale of electric power network,complex structure,variable operation mode,and complicated cooperation relationship between relay protection devices.The system operation requires high reliability of the relay protection system,especially the backup protection system.At present,the backup protection system is generally based on the traditional offline setting method,which has a large setting workload and low calculation efficiency.Under the modernization of power grid,the development of online setting technology for power system has received wide attention,which can adjust the protection setting value in real time according to the change of power grid operation mode.However,the mechanism and key technology of online setting have not yet been broken through,and the specific algorithm and process are not clear enough,which needs to be studied in depth.Firstly,this paper discusses the protction logic level progression relationship between two types of protection methods,current protection and distance protection,analyzes their operation process,deeply studies the inherent conflicts between the two types of protection methods in terms of setting method,calculation process and multiple setting principles,analyzes and sorts out the key problems of offline setting and online setting technology of grid backup protection according to the long-standing phenomenon of main protection and backup protection misoperation or rejection in the power grid,and determines the problem of setting ”deadlock” logic defects caused by the ”level-by-level cooperation” principle in online setting of complex ring network backup protection at the present stage.Secondly,the relationship between changes in grid operation directly affecting the back-up protection settings is used as a benchmark,the three methods of online setting of backup protection based on incremental factor method,generative adversarial net,and minimum protection cooperation relationship disconnected set update method for grid topology change are compared and analyzed to compare their respective theoretical advantages and disadvantages,algorithmic processes,implementation difficulties and final application effects.Finally,the method of optimal online setting of backup protection for complex ring networks is proposed.The method precisely reveals the connection between system operation mode change and protection cooperation relationship,and adopts the combination of incremental factor method and minimum protection cooperation relationship disconnected set update method to carry out online setting using different methods for different operation mode change situations in complex ring network,which integrates to form the online setting method for backup protection in complex ring network.After that,the online setting model of backup protection of complex ring network is built,the specific process and detailed implementation scheme of online setting of backup protection are given,and the validity and feasibility of the method are verified by comparison with the analysis of calculation cases.