Research On The Capability In Absorbing High-proportion Distributed Photovoltaic Power Generation In Yangzhong Grid

In 2016,Yangzhong was granted a high proportion of new energy demonstration city.According to the plan,after the ultra-high permeability distributed power supply is connected to Yangzhong power grid,it will be distributed in 220V-10 kV low voltage level on the user side,with a wide distribution area and a small single power supply capacity.Multi-access points,multi-voltage levels and decentralized access to medium and low voltage power grids bring risks to the safe and stable operation of power grids,and bring great challenges to power grid planning and economic dispatching operation.In order to support the construction of Yangzhong green energy island and high-proportion new energy demonstration city,the ability of Yangzhong grid to accept high-proportion distributed photovoltaic power generation is studied in depth,and the adaptive verification strategy of photovoltaic access is proposed.(1)Establish the mathematical model of distributed photovoltaic access to Yangzhong power grid,the power output model and load model of photovoltaic power station,introduce the conditions and grid-connected model of photovoltaic access to power grid,elaborate the topological structure of inverters and the principle of control system,and summarize in detail the construction standards of photovoltaic power station and the technical requirements of photovoltaic grid-connected.(2)A new distributed photovoltaic acceptance checking strategy is proposed.Taking the 110 kV Xilai Subarea of Yangzhong Power Grid as an example,the power supply security level,load capacity,short-circuit current and power quality factors are checked separately.The checking strategy includes strong irradiation heavy load,strong irradiation small load,weak irradiation heavy load and weak irradiation heavy load.Voltage deviation and voltage fluctuation are calculated under four operating scenarios of small load.Corresponding control measures are proposed to verify the validity of distributed photovoltaic acceptance verification strategy from multiple perspectives.(3)A fast evaluation method for distributed photovoltaic planning scheme is proposed,which is suitable for the situation of lack of accurate basic data in the early planning stage.By checking several key constraints,the rationality of the photovoltaic access scheme can be rapidly evaluated.It has the advantages of strong data quality adaptability,simple and fast calculation,and easy to be popularized in engineering.Point.The mathematical model and process steps for rapid evaluation of distributed photovoltaic planning schemes are constructed.The correctness and practicability of the proposed evaluation method are demonstrated by examples and examples respectively.The verification results of distributed photovoltaic capacity of Yangzhong power grid show that the maximum capacity of distributed photovoltaic can be accepted by the grid is constrained by the technical indicators such as power supply security level,equipment load rate,short-circuit current and power quality.The power supply radius and outlet line can be obtained through continuous modification and iterative calculation of access capacity.To a great extent,the capacity of grid to accept distributed photovoltaic(DPV)is affected by the load received.The proposed method and strategy can be well applied to the adaptability analysis of distributed photovoltaic power generation connected to power grid.It has been successfully applied in Yangzhong power grid and verified by an example.The research results of the project provide valuable experience for the planning and construction of a high proportion of new energy cities.