Research On Automatic Contingency Selection Based On Aggregated Theory And Active Safety Correction Strategy

With the continuous advancement of the global energy interconnection strategy and the strong smart grid strategy,the modern electric power network is moving toward the high voltage,long distance,large capacity development and the trend of the depth of the regional power grid interconnection.However,the increasingly large and complex topology faces failures,and the chain reaction it triggers will have serious consequences that are incalculable for the society's politics,economy,and people's daily lives.Therefore,how to ensure the safe operation of the power system has been widely considered by the academic and engineering circles,and is one of the key problems in the operation of the power system.Static security analysis is an important branch of the power system security analysis,and it is also one of the important measures to ensure the safe and stable operation.It can help the staff to take countermeasures as soon as possible based on the results of the expected accident analysis,so that the power system can be transformed from an unsafe normal state to a safe and normal state.The rapid formation of the electrical network topology structure is a prerequisite for the development of static security analysis.Based on this,it further implements the expected accident selection and its corresponding active safety correction strategy.However,with the development of the interconnected power grid,the above problems face multiple difficulties such as efficiency and complexity.Therefore,it is necessary to explore new methods to deal with them.Thus,this article focuses on the static security analysis of large-scale interconnected power grids and conducts the following three aspects:Firstly,based on the brief introduction of the research status of power network topology segmentation and the basic theory of complex networks,this paper proposes a parallel topology analysis pre-processing strategy for power grids,and uses the GN splitting algorithm to discover and analyze the community structure of actual power grids.A method for topology reconstruction based on the switch path function set for the area network in which the switch state changes has been proposed,so that the entire power network topology can be updated,and the overall network topology analysis speed can be accelerated.It lays the foundation for the safety analysis of the power system.Secondly,the basic connotation of aggregation theory was introduced into the automatic contingency selection.From the perspective of aggregation,a new method of anticipating accident selection was proposed by constructing the aggregated mathematical model.From the point of the combination of power flow distribution and topology structure,the system overload indicators are proposed to identify the key lines in the expected accident screening,and in combination with the community discovery algorithm,the identified transmission lines are constructed as aggregates and their tie lines are taken as the expected accident set.Finally,in order to eliminate the overload,an active safety correction strategy is proposed.Based on the DC power flow algorithm,we deduced the power sensitivity matrix between the line power variable and the node injection power variable,and constructed a comprehensive sensitivity matrix.Based on the inverse equal-pair matching principle,the active safety correction model is constructed to solve the problem.This method can quickly obtain the best control node for emergency control and the corresponding power adjustment amount.It can quickly eliminate the overload current while ensuring that the normal branch is not overloaded.In this way,the occurrence of cascading failures within the polymerization grid is avoided.