Risk Assessment Of Distribution Network In Xixian With Random Photovoltaic Power Supply

With the continuous progress of my country’s urbanization,the development of urban distribution networks has received more and more attention.The distribution network is directly connected to users and is a key link in the supply of electric energy.In order to accurately assess the operation risk of the distribution network and quantitatively analyze the uncertainty of the operation of the distribution network,considering the increasing penetration rate of distributed power in the distribution network,on the one hand,it has improved the recovery ability of re-supply after a failure,on the other hand,The formulation of risk assessment strategies for distribution networks has an important impact.This paper takes into account the randomness of photovoltaic output and uses risk assessment methods to study the operation risks of the distribution network in Xixian area.The main tasks are as follows:(1)In-depth study of the theoretical system of distribution network operation risk assessment with distributed power generation,focusing on the concept and definition of distribution network risk assessment,identification of risk sources in distribution network,construction of distribution network operation risk assessment index system,and risk Evaluation strategy,etc.(2)Grid-connected distributed photovoltaic power sources with high penetration rate have adversely affected the operation of the distribution network.First of all,start with the research on the main factors affecting photovoltaic power generation,and predict the probability distribution of photovoltaic output based on the dynamic Bayesian theory to deal with the randomness of photovoltaic output.In order to explore the risk of exceeding the limit of node voltage and branch power,the enumeration method and Monte Carlo sampling method are used to calculate and study the operation risk of the distribution network with photovoltaic output.A 28-node distribution network in Xixian area is taken as an example for case analysis,To verify the effectiveness of the evaluation method.(3)Based on the above-mentioned distribution network operation risk assessment strategy,a risk assessment case analysis was carried out around a distribution network hotovoltaic power generation,and predict the probability distribution of photovoltaic output based on the dynamic Bayesian theory to deal with the randomness of photovoltaic output.In order to explore the risk of exceeding the limit of node voltage and branch power,the enumeration method and Monte Carlo sampling method are used to calculate and study the operation risk of the distribution network with photovoltaic output.A 28-node distribution network in Xixian area is taken as an example for case analysis,To verify the effectiveness of the evaluation method.(3)Based on the above-mentioned distribution network operation risk assessment strategy,a risk assessment case analysis was carried out around a distribution network containing distributed photovoltaic power sources in Xixian area.Establish an operational risk assessment model and combine the actual operating parameters of the distribution network to conduct operational risk assessment research on the distribution network under different grid structures and different photovoltaic power penetration rates in different periods,and comprehensively compare its operational risk assessment results.On the one hand,The validity of the distribution network operation risk assessment method proposed in this paper considering the randomness of photovoltaic output is verified.On the other hand,the research demonstrates the change trend of the distribution network operation risk level with the increase of photovoltaic power penetration rate.