Studies On Methods Of Network Partitioning For Voltage Reactive Power Control Based On Short-circuit Impedance Distance And Reactive Power Margin

With the continuous development of powe system and the expansion of power grid,voltage stability problems are becoming increasingly prominent. Implementation ofvoltage reative zone control is an important measure to emprove voltage stability ofpower system, and has a great significance to prevent voltage instability, improve thevoltage level, and reduce the network loss. How to divide the power grid to couplingloose region is an importan task. Based on this, the paper study on methods of networkpartitioning of voltage reactive power control. Specific contents are as follows:①The typical mothods of network partitioning of voltage reactive power controlare introduced accordingly in this paper, including the principle of voltage reactivepower partition, the characteristics of the sensitivity distance and the simulation of itscharacteristics, introduction of hierarchical clustering method. All the introductionprovides theoretical basis for the mathods proposed in this paper.②A novel partitioning method is proposed based on power sources clustering andshort-circuit impedance distance, which is characterized by Mvar source nodespartitioning and load nodes mapping. This method completes the partition by two stepsas follows:(1) The electrical distance between two Mvar source nodes is defined basedon the sensitivity of voltage to reactive power injection, and the agglomeratehierarchical clustering algorithm is applied to partition the Mvar source nodes;(2) theshort-circuit impedance distance between multiple Mvar source nodes and a single loadnode is defined, and the mapping between load nodes and Mvar sources partitions isrealized by minimizing the short-circuit impedance distances. Simulation results onIEEE39-bus system and the real Chongqing grid data demonstrate the effectiveness ofthe presented method.③An optimization model of network partitioning for voltage reactive powercontrol considering reactive reserve was established. And evolutionary programmingwhich is based on target relative dominant strategy was used to solve the model. Thispaper difined effective dynamic reactive power margin and established multi-objectiveoptimization model of network partitioning for voltage reactive power control, whichhas three objective function including strong coupling in a region, weak couplingbetween regions and sufficient reactive power margin. To solve the contradicitionbetween multiple objective function, a target reactive dominant strategy is proposed to define the optimal solution. Then according to the features of the optimization model ofnetwork partitioning for voltage reactive power control, partition variable coding,random mutation strategy, computation for fitness value and selection operator fouraspects of evolutionary programming is improved to ensure the effective of algorithm.The optimization method of network partitioning proposed in this thesis has beenverified by IEEE39-bus standard system, the simulation results proved that they arecorrect and effective.