Research On Reactive Power And Voltage Control Zoning Method Considering Weak Coupling

With the increasing complexity of the grid structure and the continuous integration of large-scale wind turbines,the voltage stability of the power system has been affected.Therefore,it is necessary to adopt reasonable voltage monitoring methods to ensure the safe and stable operation of the power grid.As an important means of voltage control,voltage division can divide the system into several areas with voltage stability.The traditional voltage control area division process is more complicated,and lack of consideration of the impact of disturbance on the division.Therefore,based on the voltage coupling between the system node and each(Voltage Control Area,VCA),this paper conducts a comprehensive research on the voltage control partition method.The specific work includes the following aspects:The voltage control zone model usually refers to the voltage sensitivity and electrical distance of the system.The traditional voltage control zone model only considers the influence of reactive power on the voltage zone,and cannot fully consider the influence of the unit output on the zone.Therefore,this paper proposes a voltage control partition model that includes active power.First,the Jacobian matrix is obtained by Newton-Raphson method of power flow calculation.Based on the coupling of power and node voltage,the partial conductance elements of reactive power and active power to voltage amplitude are comprehensively selected to construct the sensitivity structure of the load node.Secondly,the sensitivity is mapped to the electrical distance matrix of the load node,and the PQ node partition is performed using the agglomerated hierarchical clustering algorithm based on the Ward distance.Finally,according to the idea of reactive power source control space,the PV nodes are merged using the successive recursion method to realize the whole network partition.On the basis of the above research work,considering that the results of the zoning will change with the fluctuation of wind power output,a method for improving the stability of the zoning using disconnection analysis is proposed.Based on the coupling between the VCAs,the disconnection analysis of the regional boundary branch is carried out,and the boundary nodes are corrected and partitioned according to the similarity of the voltage changes before and after the disconnection,and a more stable partitioning result is obtained.The partition model in the article can reflect the changes in the active power output of wind turbines,and is suitable for the study of voltage control partitions under wind power integration.The disconnection analysis method proposed in the article can correct the boundary nodes with inconsistent voltage changes in the region,and obtain the regional results with a higher degree of regional voltage decoupling.The article comprehensively considers the coupling of node power and voltage,and the degree of decoupling of the regional boundary,which provides the conditions for the stable and accurate partition of the system.Through the simulation analysis of the IEEE39-bus system,the rationality and effectiveness of the proposed method are verified.