Distributed Power Restoration Method For Smart Distribution Grid With SOP And ESS

Intelligent distribution network is an important part of smart grid construction,and the power supply reliability is a significant comprehensive indicator to measure distribution network performance and user satisfaction.Once fault occurs,the power supply reliability will be seriously affected,and the power supply must be restored as soon as possible.In addition,the access of flexible power electronic devices to the distribution network bring distribution network with new operating characteristics,such as flexible adjustment characteristics of soft open point(SOP),which makes more complex operation control,and energy storage system(ESS)promotes the consumption of distributed energy resources in distribution network,increase the number of distributed generation(DG)connected to the distribution network.At the same time,the operation information of the distribution network is increased,the structure is more complex,and the scale and difficulty of the power restoration problem expands rapidly.The traditional centralized restoration algorithm is based on global scale information interaction and calculation,which has been difficult to meet the structural and operational changes of the distribution network.Therefore,it is significant to study a power restoration method that is suitable for the structure and operation characteristics of distribution network,with good rapidity and strong adaptability.This paper proposes a distributed power restoration method with SOP and ESS for the intelligent distribution network,which can be used to disperse the smart terminal units(STU)as the core,based on the distributed topology and electrical quantity information of the distribution network,to achieve fast distributed computing of recovery constraints.On this basis,considering the various control methods and output adjustment characteristics of adjustable and controllable devices such as SOP and ESS,proposes an output adjustment strategy adapted to the distributed power restoration process to expand the scope of power restoration.First of all,this paper expounds the basic principle of the distributed power restoration method.The implementation of the method is divided into two steps:firstly search for non-faulty power outage areas,and then to determine the actual recoverable area.In distributed constraints solving process,the step-by-step Thevenin equivalent method is used to calculate the electrical constraints of each node.At the same time,it analyzes and deals with various types of power supply,multi-branch,multi-load priority and so on.For the situation that the power electronic controllable device is connected to the distribution network,the principle analysis and adjustment measures are made in each step of the distributed power recovery method.Secondly,this paper proposes a distributed power restoration method with SOP.The mathematical model,operation constraints,control methods and implementation of SOP are introduced.To take advantages the control strategy and output adjustment characteristics of SOP,based on the different control modes of SOP,an adjustment strategy is proposed,which fully demonstrates the supporting role of the SOP on restoration.Aiming at the situation of multiple SOPs in the same power outage area,a coordinated adjustment strategy of multiple SOPs in the distributed power restoration method is proposed to further improve the restoration level.At last,based on the flexible operation and adjustable controllability of charging and discharging modes of ESS,a distributed power restoration method with SOP and ESS is proposed.Three ESS models for power recovery are established,and the adjustment strategies of ESS and SOP in distributed power recovery are proposed according to the characteristics of the three models,and the adjustment and coordination of the two types of devices are realized to obtain the maximum possible range of restoration.Based on the distribution network data of the IEEE33-node and IEEE69-node system,this paper verifies the distributed restoration method with SOP and ESS proposed by setting different scenarios.The example analysis shows that the distributed power restoration method with SOP and ESS proposed in this paper has excellent restoration ability,and takes shorter time and wider range of restoration results.The proposed adjustment strategy under various control modes of SOP and ESS improves the power recovery level of the distribution network and lays a good foundation for improving the reliability of the power supply of distribution network.