Research On Risk Assessment Considering The Influence Of Distributed Power Generation On Distribution Network Voltage

With the increasing scale of distributed power generation such as photovoltaic power generation and wind power generation in recent years,more and more distributed power sources are connected to the power system,bringing new characteristics and challenges to the traditional power system dominated by thermal power Researchers put forward a large number of research topics.The access of distributed power sources will inevitably affect the security of the power grid and the reliability of users’ electricity.This thesis studies the voltage impact caused by distributed power sources connected to the distribution network,and establishes a corresponding distribution network risk assessment system,studies and improves the risk assessment method,and uses examples to verify the effectiveness and superiority of the improved method.Firstly,the principle of power generation of distributed power is explained,the output power model of photovoltaic power generation and wind power generation is established,and the random distribution probability model of active power and reactive power of the load is established to pave the way for the following calculations.Secondly,a detailed study is made on the influence of the access of distributed power sources on the node voltage of the distribution network.When a single distributed power source is connected,the law of the influence of different capacities and different locations on the voltage of the distribution network is analyzed.Predecessors have rarely studied the simultaneous connection of multiple distributed power sources,so they analyzed the simultaneous connection of multiple distributed power sources.The relationship between the number,capacity and location of different connections and the changing trend of the voltage in each section is described,and then the law of the influence of multiple distributed power sources on the voltage of the distribution network is summarized.In order to improve this influence,the solution to connect to typical controllable loads represented by electric vehicles is studied,and the IEEE33-node power distribution system is used as an example to verify the above rules,and different electric vehicle access schemes are compared.Came up with the best solution.Then,compare the currently commonly used risk assessment methods for distribution networks.Comparing the respective characteristics of the analytical method and Monte Carlo simulation method,the Monte Carlo simulation method is more complicated in modeling,requires variables to obey a certain probability distribution,requires repeated iterations,and has a large amount of calculation.The combination of two important use techniques of Equal Dispersion Sampling and Importance Sampling has formed an improved Monte Carlo simulation method.The improved method largely overcomes the shortcomings of the original two methods and has their advantages.Finally,based on the influence of distributed power sources on the voltage of the distribution network,a risk assessment system for the distribution network was established,and the improved Monte Carlo method,importance sampling method,and other decentralized sampling methods were used to conduct risk assessment on the IEEE33 node distribution system.,Comparing the calculation results of the three methods to verify the effectiveness and superiority of the improved method.