| In recent years,the massive use of fossil fuels has triggered a series of climate problems,leading to frequent extreme weather events everywhere.Extreme weather has the characteristics of large scope and strong destruction,which has caused a great impact on the daily operation of the power system.In particular,typhoons,heavy rain and lightning have caused huge losses to the developed areas along the southeast coast,affecting people’s daily life and economic development.At the same time,China’s economy is in a stage of rapid development,the scale of the power system is also expanding,and the dependence of users on electric energy is further deepening,so the impact of extreme weather on the power grid will continue to intensify.Therefore,analyzing the impact of extreme weather on the power system,identifying the weak links of the power system in advance,optimizing the operation strategy of the power grid,and combining multiple resources to improve the resilience of the power grid can reduce the impact of extreme weather on the power system.At the same time,as a resource with spatiotemporal characteristics,mobile energy storage devices can realize the flexible distribution of electric energy in time and space.Combining mobile energy storage with distributed power and network optimization can improve the ability of power systems to cope with extreme weather.Based on the above background,this paper proposes a distribution network optimization operation strategy considering extreme weather and mobile energy storage flexibility.Firstly,taking typhoon weather as an example,the typhoon movement speed and movement angle model is established.Based on the typhoon model and the rainfall caused by the typhoon,the wind field and precipitation model were established.By analyzing the influence of wind and rain on the distribution network,the failure probability model of the distribution network tower and line components under typhoon weather is established,and then the fault probability model of each transmission path is established.With Monte Carlo simulation,fault probabilities are used to generate distribution network failure scenarios under extreme weather.Then,a case analysis is carried out to verify the effectiveness of generating fault scenarios,which is used to serve the two-stage optimization operation strategy of distribution network considering the flexibility of mobile energy storage.Based on the flexibility of mobile energy storage,the spatiotemporal movement characteristic model and energy characteristic model of mobile energy storage device are established.Then,the distflow power flow model and network reconstruction model of distribution network are given,and the model of distributed power generation and the safe operation constraints of distribution network are given.Furthermore,a pre-disaster pre-allocation model of the distribution network with the goal of weighted and minimal loss of load in stagel 1 is given.The post-disaster dispatching model of the distribution network in the stage 2 is presented with the goal of minimizing the comprehensive power supply cost composed of load reduction cost,power generation cost,energy storage device moving cost and charge and discharge loss cost.Before extreme weather occurs,according to the generated distribution network fault scenarios,the distribution network topology is pre-adjusted to avoid weak line power supply.At the same time,the position and state of charge of mobile energy storage are pre-adjusted,that is,mobile energy storage devices are placed near important loads and charged to a full state before disasters.And adjust the distributed generator to the maximum output power to achieve the least loss of distribution load when extreme weather comes,ensure the power supply of important loads,and weaken the impact of extreme weather on the distribution network.After extreme weather,real-time dispatch of mobile energy storage devices,change network topology and distributed power output,use the spatiotemporal flexibility of mobile energy storage devices to improve the spatiotemporal distribution of power in the network to achieve the minimum comprehensive operating cost,and also ensure the high power supply level of the system after disasters and improve the flexibility of the distribution network.Finally,the improved IEEE-33 node power distribution system is used to compare and analyze the examples under the three schemes,and the effectiveness of the proposed model is verified.The results show that in the operation of distribution network optimization,considering the impact of extreme weather on the distribution network,combined with flexible resources such as mobile energy storage devices,the reliability of power supply can be improved and the power supply of important loads can be guaranteed.It not only improves the flexibility of the distribution network,but also takes into account the economy of system operation,and effectively improves the ability of the distribution network to withstand typhoon disasters. |
