Voltage Zoning Coordination Control Of Distributed Photovoltaic Power Network With High Permeability

With the introduction of a series of policies and the support of advanced technology concepts,it is foreseeable that distributed photovoltaic power generation will show a blowout development in China.In recent years,the penetration rate of distributed photovoltaics in the distribution network has continued to increase,prompting it to play an increasingly active role.That is,by controlling the power output of the photovoltaic itself,actively participate in the voltage regulation of the distribution network to ensure the safety and stability of the power grid.However,although the related technologies of distributed photovoltaic grid-connected networks are relatively mature,there is still a phenomenon of abandoned light.Therefore,it is of great significance to solve the problem of voltage deviation of distribution network with high permeability distributed photovoltaics and to improve the absorptive capacity of distribution network for distributed photovoltaic power generation.This paper focuses on the voltage division coordination control strategy of distribution network with high permeability distributed photovoltaic.Firstly,the paper introduces the complex power transmission increment to reflect the electrical connection between any two nodes in the power grid,and elaborates the concept of the complex power transmission increment and its calculation method.Subsequently,the partition theory based on complex power increment matrix is studied.By analyzing the idea of system partition in graph theory,the threshold search method is introduced.Aiming at the uncertainties of some critical nodes in the initial partitioning scheme obtained by the algorithm,the final partitioning scheme is obtained by adjusting and improving the initial partitioning scheme by dynamic decentralization method.The validity of the zoning method is verified by an example analysis.Secondly,the theory of controlling the output of photovoltaic power supply is emphatically studied in view of the distribution network that has been partitioned.By studying the mathematical model of power control strategy for single photovoltaic inverter,the corresponding PQ(U)control structure is built.Subsequently,the algorithm flow of in-area preventive control,inter-area reactive power coordinated control,inter-area active power coordinated control and inter-area power recovery control in voltage partition coordinated control strategy of multi-photovoltaic inverters is studied in detail.Finally,based on the simulation software PSCAD,the PQ(U)control model of grid-connected photovoltaic inverters is built,and the voltage and power control strategy of single photovoltaic inverters is simulated and verified.The process of voltage partition coordinated control strategy with high permeability distributed photovoltaic is simulated,and the voltage regulation effect is compared with decentralized in-situ control and direct abandoning light control strategies.The results show that this method can significantly improve the permeability of distributed photovoltaic,maximize the use of natural resources and protect the interests of photovoltaic power owners.