Operation Reliability Evaluation Of Interconnected Power Grid Based On PMU Monitoring Data

Global grid interconnection has become the trend of future power grid development.While improving the reliability of the grid,the interconnected grid also provides conditions for the spread of risk.Online assessment of the reliability of each regional grid is of great significance for the safe operation of the interconnected grid.On the one hand,the interconnected power grid system is huge,the topology is complex,and it is limited by the limited computing power of modern computers.It is difficult to evaluate the reliability of the entire interconnected grid in a short period of time.On the other hand,the vertical management system between the grids of the interconnected grids and Factors such as the principle of commercial secrecy make it difficult to share information between interconnected power grids in real time.The regional power grid cannot timely detect the impact of changes in operating modes caused by faults,load fluctuations,and generator output adjustments on the reliability of the region.The static equivalent method of the power system can simplify the interconnected power system and greatly reduce the time taken for reliability assessment.However,the traditional equivalent model is too simplistic and it is difficult to get practical application in the solution process without considering the problem of information isolation between interconnected grids.How to obtain an accurate externa l network equivalent model in the case of information isolation,evaluate the reliability of the grid operation in the interconnected power grid,and calculate the reliability index of the interconnected grid regional grid is a difficult problem for the sa fe operation of the interconnected grid.Aiming at the difficulties in the reliability evaluation of interconnected grid regional power grid operation,the paper proposes an interconnected grid operational reliability assessment method that does not rely o n external network information and only uses boundary PMU measurement data and intranet real-time data.The method uses the sensitivity consistency(SCSE)static equivalence model to simplify the interconnection of external networks.The real-time monitoring data based on the boundary PMU is used to update the external network equivalent model parameters online,and the reliability of the interconnection network regional grid operation is evaluated to obtain the corresponding regional power grid.Reliabilit y indicator.The paper includes the following:(1)Introduce the SCSE equivalent model.Introduce the basic concepts of static equivalence of power systems,including the concepts of external systems,internal systems,and boundary systems;introduce the c onventional ward equivalent method,give the ward equivalent model parameter derivation process and calculation steps;explain the use of SCSE,etc.The necessity of the value model,because the conventional ward equivalent is strictly mathematical equivalent,ignoring the sensitivity relationship of the system before and after the equivalent,the ward equivalent model has large errors and is not easy to converge,and the existing static equivalent model of the power system The SCSE equivalence model considers the sensitivity relationship of the system before and after the equivalence and has the advantages of small error and high convergence after the change of the operating state of the system.Therefore,the paper uses the equivalence model to simplify the external network.The concept of sensitivity between the external system and the internal system of the interconnected grid and the specific derivation process of the sensitivity relationship,the SCSE equivalent model and the parameter calculation metho d.(2)A model for estimating SCSE equivalent model parameters based on boundary PMU monitoring data is established.Based on Kirchhoff's law,the corresponding parameter measurement equations are derived.To ensure the accuracy of the estimated parameters,a least squares model is established and the global search method is used to solve the measurement equations.Based on the above estimation model,the IEEE-RTS-96 test system is used as an example to estimate the model parameters in 13 different operatin g states and compare them with the actual values.(3)Assess the reliability of regional grid operations.The specific steps of regional network operation reliability assessment are given,the AC optimal power flow model is introduced,and the reliability index is given.Taking the IEEE-RTS-96 test system as an example,the operational reliability indicators in 13 operating states are calculated and compared with the other two regional grid operational reliability assessment methods to illustrate the effect iveness of the proposed method.