Research On Power Grid Stability Situation Based On Transient Potential Energy In Wide Area

Under the background of the new era,the power grid interconnection scale is unprecedented and ensuring the safe and stable operation of the power system,especially the transient stability after the accident,has important influence of the overall system.At present,the construction process of smart grid is accelerating constantly in the world.The comprehensive coverage of wide area measurement technology and highly connected communication network can provide sufficient precision and speed in the unified angle of time and space,measuring the real mass operating state information of the total network,which can bring new opportunities for network transient stability and security situation assessment.The research ideas of this paper are carried out from transient energy,obtaining the state data of the network through the wide area measurement information?WAMS?.The transient potential energy and the load transient potential energy model are established respectively,and the relationship between the two and the stability of the system is obtained,which can provide valuable reference information for online security analysis,stability control and situation prediction.The WAMS data acquisition and transmission system is briefly introduced to facilitate the formation of macroscopic data awareness.The mechanism of transient stability based on unbalanced power is analyzed through rigorous mathematical deduction and discussion.Whether single or multi machine systems,the essence of transient stability is whether energy eliminating is balanced.Then the analytical perspective is extended from the generator to the whole network,obtaining the branch transient potential energy model and load transient potential energy model,excavating more abundant information about transient stability characteristics from the whole network level.A large number of simulation calculations are carried out based on the BPA platform of the power system simulation integrated environment of china academy of electric power science and MATLAB.On the one hand,based on the branch transient potential energy model,the relationship between the transient potential distribution characteristics of the branch and the stability of the system is compared under the different fault delay and the power flow level.The results show that a few branches are always the first to concentrate the majority of transient energy and form the weak link of the whole network.When the system is unstable,the system is often"tearing"on the cut set of this part of the branch.Based on the function extreme value idea,the branch stability measure function is constructed,which can dynamically monitor the stability of the branch and selectIV_B^1.2as the reference value of the pre-judgment,and first find the fragile branch of the network.The calculation results of IEEE39 bus system example show that the index application is effective.It is considered that the maintenance of transient stability is often accompanied by corresponding emergency control measures,and the load cutting strategy is explored from the angle of load transient potential energy.The simulation results show that cutting the load with less transient potential energy sharing is more conducive to maintaining the stability of the system.Therefore,a load shedding sequence index is proposed,which takes account of the volume of the removed objects and the location of the fault points to determine the order of removal.The simulation results show that cutting the load with less transient potential energy sharing is more conducive to maintaining the stability of the system.Therefore,a load shedding sequence indexIC_Li is proposed,which takes account of the volume of the removed objects and the location of the fault points to determine the order of removal.The IEEE39 node system example shows the practicability of the proposed method,and provides a feasible solution for further implementation of online active defense for emergency control.In order to fully grasp the security and stability level of the power grid,the demand analysis of the power grid situation security visualization is carried out,and the WEB visualization situation monitoring platform is put up.Depending on the logical system architecture model and the powerful rich ECharts development tool,the information platform is designed,which integrates the geographic information visualization,the operating condition monitoring and the stable data chart.The platform greatly enhances the readability of WAMS data,and can become a window of intelligent,efficient and convenient operation monitoring personnel real-time perception of the security and stability of the whole network.