Research On Hierarchical Control Strategy For Distributed PV Distribution Network

Distributed photovoltaics are often connected to the distribution network in a highdensity and decentralized form.The output has strong randomness and intermittence,showing the characteristics of multi-point,wide range and high permeability.When the traditional centralized scheduling method is applied to large-scale distributed photovoltaic power access,there are problems such as complicated control objects,huge communication data,and low reliability,which cannot adapt to the coordinated optimization of a large number of power sources in the region.In view of the characteristics of distributed power supply in Shandong power grid,this paper proposes a hierarchical hierarchical control strategy based on the design idea of the Internet of Things architecture,which is applied to the distribution network of distributed photovoltaic cluster grid connection.In the two levels of group control and group adjustment between photovoltaic clusters and the autonomy of the platform area within the cluster,the active and reactive power of the distribution network is adjusted.Starting from the mechanism of affecting the voltage distribution of distribution network,combined with the characteristics of distributed photovoltaic power generation dispersion and the requirements of unified management,the hierarchical hierarchical control architecture of distributed photovoltaic cluster grid-connected control was designed by referring to the advanced concept of Internet of things.The hierarchical control architecture of the distribution network was based on the idea of inter-group coordination and intra-group autonomy to coordinate the active and reactive power of the node voltage in the cluster.The inter-group coordinated control strategy of the distribution network was studied,and the active and reactive power are decoupled.The distribution network was divided into clusters based on the voltage sensitivity matrix.The voltage of the nodes in the cluster was operated within the safe range and the regional network loss was minimized.The improved IEEE33 node typical system was selected as the analysis object,and the inter-group coordination optimization model under the safe operation scenario of the dominant node voltage and the over-limit scenario was solved.The effect of inter-group coordination optimization strategy on suppressing node voltage deviation and reducing system network loss in different scenarios was analyzed.The autonomous control strategy of the station area within the cluster was studied.Based on the step-by-step control of active and reactive power,the active and reactive power cooperative control strategy was proposed.The disturbance observation method was used to estimate the sensitivity of active and reactive power of node voltage,which solves the dependence of accurate topology and load data in the research of global optimization of active and reactive power in the station area.The inverter in the station area maintains the voltage stability in the station area and reduces the network loss by performing active and reactive power coordinated voltage regulation.The improved IEEE33 node typical system was selected as a cluster for analysis.The autonomous optimization model in the group was solved in the scenarios of safe operation of node voltage,mild over-limit and severe overlimit.The effect of reducing system network loss and node voltage deviation and maximum local consumption of photovoltaic in different scenarios was analyzed.The hierarchical control strategy with distributed photovoltaic distribution network was applied to the test experiment of #2 area of Pinganyu West Substation in Linqu County,Shandong Province.By analyzing and comparing the application effects of active and reactive power regulation,the effectiveness of the proposed autonomous strategy of the station area to reduce the node voltage deviation and improve the voltage quality was verified in multiple scenarios.For every 10 k W reduction in the total active power output,the average node voltage decreases by about 0.746V;for every 10 kvar increase in the total amount of reactive power absorbed,the average node voltage decreases by about 0.931 V.The 10 k V Ping ’an line under the Yeyuan Power Supply Station of Yeyuan Street in Linqu was optimized and regulated.After the control instruction was issued,the reverse current of the feeder decreased by 120 A,and the reverse load rate decreased to about 60%.The hierarchical control strategy helps the distributed photovoltaics under the jurisdiction of local power grids to be consumed locally,and provides new ideas for improving the reliability and economy of distribution network operation.