Research On Power Flow Calculation Of DC Distribution Network And Residential Power Consumption Optimization

With the development of distributed generation and power electronics technology,DC distribution network based on voltage source converter(VSC)has the advantages of flexible access,high reliability and good economy.On the other hand,with the development of smart grid and the price incentive brought by the reform of power market,resident users play an increasingly important role in demand response(DR).Firstly,the topology and working principle of VSC and DC/DC converter are analyzed in detail,and the steady-state power flow models of VSC and DC/DC converter are established.The typical operation control strategies of DC distribution network are analyzed based on the power flow model of VSC,and the power flow calculation method of multi-terminal DC distribution network based on VSC is studied.In the process of power flow calculation,a method of automatic searching and open-loop processing for network structure based on node correlation matrix is proposed.Considering that the traditional power flow algorithm can not deal with the sagging nodes in DC distribution network,a unified power correction matrix for ring network and sagging nodes is established,and a unified power correction method for ring network and sagging nodes is proposed.The power limitation of VSC and the conversion of its control mode are considered.Finally,a modified IEEE14-bus DC distribution network example is used to verify the validity and correctness of the proposed power flow calculation method for DC distribution network.Secondly,this paper analyses the dispatchable characteristics of household appliances in detail,classifies and models household appliances,and establishes the optimization model of household appliances with the objective of minimizing household electricity consumption cost.Considering the influence of different time-sharing tariffs on the responsiveness of household users,the constraints of load transfer rate for household electricity optimization are proposed.Considering the uncertainty of household users' responsiveness,the fuzzy chance constraints method is adopted.The steps of population initialization,crossover and mutation of genetic algorithm are improved,and the improved genetic algorithm is used to solve the household appliances optimization model.Finally,an example shows that the proposed model can effectively reduce residential electricity consumption and reflect the impact of electricity price on residential load response.