Research On The Effect And Countermeasures Of Inverter Distributed Power Supply On Feeder Automation

With the rapid development of the national economy,the primary energy sources which are mainly fossil fuels such as coal and oil are less and less.Moreover,the traditional energy has a serious impact on the bad environment.In order to solve the increasingly serious deterioration of the bad environment,the distributed generation is getting more and more attention.With the development of economy and society and the support of national policy,the small power distributed new energy generation has been gradually connected to the 10 kV distribution network in recent years."13th Five-Year" period,The penetration of all kinds of distributed generation in distribution network has been greatly improved.The large number of access and high penetration of distributed power make distribution network a power distribution and switching network.The power flow of the distribution network is changed from one-way to two-way,and the distribution network is changed from passive network to active network.Nowadays,the design of feeder automation terminals in distribution network is based on one-way flow.A series of operation errors occur from bidirectional flow caused fault location,isolation and non fault area recovery,which will affect the safe operation,regulation and fault handling of distribution network.Therefore,it is of great significance to study the influence of distributed power supply on the feeder automation of distribution network.Based on the current four mainstream modes of feeder automation,this paper analyzes the working principles of various feeder automation,fault isolation,and the logical judgment mode of non fault area power supply.This paper analyzes the influence of distributed power on feeder automation from these aspects: distributed power supply is not out of network in a timely manner,island protection is not acted in time and affects the logical judgment of main station.Finally,it is verified with simulation.When the line fails,due to the different capacity and position of the distributed power supply,the distributed power has different influence on the short circuit current of the line section of the fault point,the upstream line section of the fault point and the downstream line of the fault point.This paper combines the simulation,analysis the amplitude relation and phase relation between the two ends of the fault interval and the fault interval section of the distribution network with distributed power supply and the short circuit current between the two ends of the fault zone.It lays the foundation for further research on fault location andisolation of distribution network containing distributed generation.And aiming at various types of feeder automation implementation mode,a targeted solution is put forward.For the local type feeder automation,considering the distributed low voltage ride through capability,a remote trip protection mode is proposed;For centralized and intelligent feeder automation,it is proposed to locate the fault section by comparing the phase of current at both ends of the line section.At the same time,it solves the problem that there is only one fault current at one end.Then,it is verified by simulation,and a definite logical criterion is proposed;For user demarcation feeder automation,a method based on the phase difference between current and system current is proposed.This paper based on the research of distributed power distribution network fault location,according to the influence of distributed generation on feeder automation,presents the current phase comparison method.And it validates its feasibility through DigSilent simulation.It has great significance for large numbers of distributed generations to access the distribution network,and lay the foundation for future research.