Reserch On Wide Area Protection Of Smart Distribution Grid

With the national Power Grid Corp building a unified strong smart grid work to start a comprehensive,China's power grid following the traditional grid,digital power grid has gradually entered the stage of smart grid.Intelligent distribution network is an important part of building a unified strong smart grid,is the future development trend and goal of distribution network.Compared to the traditional distribution network,intelligent power distribution network with high reliability,high security of the communication network as the foundation,with self-healing,strong,integration,compatibility,interaction and other features.Large capacity grid intelligent distribution network to allow distributed power,distributed power access to distribution network has changed the traditional distribution network with single power supply mode of radiation;at the same time,along with the distribution network self-healing control technology matures,operation mode of distribution network more flexible.Intelligent distribution network power closed loop operation and the complex power supply mode put forward hitherto unknown challenge to the relay protection,the traditional distribution network rely on lower switch protection fixed value with the range of delay mode gradually lose living space.Wide area protection based on high-speed information communication network as a platform,multi point and multi type information into the protection system,fundamentally reform the configuration of the relay protection,can significantly improve the performance of the relay protection.So it is very important to study the wide area protection system which is suitable for improving the reliability of distribution network with the development of intelligent power distribution system.In this paper,based on the operation characteristics of intelligent distribution network,a set of protection system configuration scheme for distribution network intelligent process is proposed.Wide area protection system of the distribution network using the hierarchical layout in logic,mutual cooperation between all levels after fault occurred in distribution network can quickly and effectively complete the location and isolation of the fault section,restore sound regional power supply etc.The distribution automation system of distribution network protection system proposed by the vast majority of distribution network based on the proposed additional requirements,not intelligent equipment of the distribution network,it has great application value in practical engineering.In order to improve the operation speed of fault processing,this paper puts forward that the correlation operation between fault section location and power supply recovery decision is completed by the station area layer of the wide area protection system of distribution network.The master level system to switch according to normal operation from the base layer to collect on-off information,complete for the topological structure of the distribution network analysis,intelligent switch clear under current operation mode power supply scope of each station and under the jurisdiction of the domain layer.After the fault occurs,the station layer only collectsthe fault information of each node in the power supply range to complete the fault section location,and reduce the calculation amount of the fault processing.This paper presents a new algorithm for distribution network topology analysis,which is based on the breadth first search algorithm.The algorithm is simple and reliable,and its physical meaning is clear.The master level by this algorithm can get the station domain related connectivity is the switch node domain during normal operation,clear in the failure process of information interaction in the object,is the basis for subsequent fault processing.Operation mode of smart distribution network is complex and changeable,the fault location technology mainly uses the existing description of the topological structure of distribution network to map,when changing the operation mode of the network need to reset the network description matrix,so that the algorithm is more complex and complicated.This paper presents a technology of distribution network fault location based on node branch incidence matrix,the algorithm only rely on between the switch node determine the connection to complete the fault section.The algorithm does not rely on a certain kind of operating mode switch on the subordinate relationship,still can determine the fault location quickly and accurately in the change after the distribution network operation mode.Distributedgenerations after changing the power supply mode of the traditional distribution network with single power radiation,this paper considers a improved scheme of fault location algorithm of node branch incidence matrix based on large capacity distributedgenerations afterThe wide area protection system of distribution network depends on the communication network of the distribution network,and the wide area protection system will not be able to complete the task of distribution network fault when the communication network is abnormal.Autonomous fault processing mode does not require the interaction of information.When the communication system is abnormal,it still depends on the setting value and the time delay to complete the fault treatment of the distribution network.This paper studies the wide area protection coordination and autonomous fault disposing mode of distribution network with the problem,put forward the autonomous failure mode as the configuration of intelligent distribution network protection,the protection of distribution network will be automatically reduced to autonomous type failure mode when the failure of the protection system,to ensure that the treatment can still more reliably in fault abnormal distribution network communication system under the condition of the fault.