Research On Reactive-power Voltage Control Partitioning Method In Power System

As an important means of the stable and economic operation of power networks,reactive power and voltage control plays an important role in ensuring the voltage quality of power systems.In reactive power and voltage control,how to partition the power grid is an important issue.Based on this,the research on reactive power and voltage control partitioning method of power systems has been conducted in the thesis.Work in this thesis can be specified as follows:The significance of reactive power and voltage control,of which power network partitioning is an essential part,was expounded.The state-of-the-art of automatic voltage control system domestic and overseas was introduced.Especially,typical methods of reactive power and voltage control were emphasized.The profile of reactive power and voltage control partitioning was introduced.The secondary voltage control is an intermediate section of three layer voltage control mode,the reactive-power voltage control partitioning has been one of the most important part of secondary voltage control;The theory of secondary voltage control is briefly introduced in this thesis.Principles of reactive power and voltage control partitioning,partition form,and commonly used definition of electrical distance are introduced in this thesis.Utilizing the K-means classification method,calculation and analysis were conducted on the IEEE-39 test system.Traditional power grid was divided.A new method of reactive power and voltage control partitioning based on combination clustering algorithm was proposed.Based on the node voltage equation of power system,the control sensitivity,from reactive power source node voltage to load node voltage,was obtained.And then,reactive power source control space was built.The combination clustering algorithm and distance evaluation function were used for power grid partitioning,where the distance evaluation function was used to evaluate the results of different cluster numbers.Hence the partitioning scheme under the optimal clustering number can be obtained.The method is applied to IEEE-39 test system,and the results show that the method was feasible and effective.Power grid with wind power integration was divided.Reactive power and voltage control partitioning method with wind power integration based on complex network theory was proposed: taking power of wind farms under various scenarios as part of the injection of power flow calculation.Voltage regulation sensitivity matrices were formed,based on which the PQ nodes can be merged and the initial partition can be obtained.After getting condensation process based on the improved Fast-Newman algorithm,the partitioning scheme of the maximum weighted module expectation value in the iterative process was selected as the final partition scheme.The validity of the proposed method was proved through the simulation and analysis on IEEE-39 test system with wind power integration.