Research On Risk Assessment And Dynamic Fault Restoration In Smart Distribution Network

In recent years,due to environmental damage,many types of disasters occur frequently,which brought great challenges to the safe and stable operation of power distribution system.Therefore,how to ensure reliable power distribution system becomes an important issue in China's current research due to the extreme environmental events.Considering the above situation,this paper studies the risk assessment before the disaster and the rapid dynamic fault recovery of the distribution network after the disaster,the study has important significance to improve the early warning capability before fault occurs and the fault recovery level after fault occurs.This paper is based on "smart distribution network situation aware and disaster response key technology research and development" project.In response to various types of disasters,the disaster management visualization system of Liaoning distribution network is developed,Which can detect the real-time running status of power distribution system through the information from the power system and meteorology,and it can achieve the evaluation of early warning,strategy development and other functions,and ultimately to a friendly interface for display.Based on the analysis of typical disasters in recent years in Shenyang and other places,this paper establishes a risk evaluation model of distribution network power failure based on fault tree selection.Taking into account the failure is caused by many factors,the same area at the same time encounter the same type of disaster,the probability of failure at different locations is different.If the risk assessment is carried out for each region,it is not only a waste of time,but also increases the risk of the system.Considering this,this paper uses the method of fault tree to diagnose the fault before the occurrence of the fault.And then can quickly alert high-risk areas.In addition,based on the seriousness of the fault after the distribution network,when the fault severity is low,which can through the operation of the switch or distributed power island operation to restore power supply load,this paper used the Breadth-first search and the improved harmony algorithm to recover the blackout load.Considering the intermittence of distributed generation and the variability of load demand,the failure recovery scheme cannot be satisfied at the next moment.In this paper,the charge and discharge balance model of energy storage and DG forecasting is analyzed,which restore the power in the outage area dynamically.Finally,the paper studies the disaster repair strategy after the disaster caused by the power.network fault and the large area blackout accident.The power grid can be restored by the micro grid operation after the disaster if it cannot be restored by main network,which to reduce the power loss caused by power failure.Therefore,this paper proposes a dynamic fault recovery strategy based on the emergency power generation vehicle as supplemental power to reduce the risk faced by the system,which considers the flexible power supply of the emergency power car.