Research On The Feeder Automation Technology Adapted To The Distributed Generation Access

After the Distributed Generation(DG)is connected to the distribution network,the size and direction of the fault current are complicated.Due to many branches in the distribution network,fault diagnosis,positioning,and isolation are comprehensive issues and need to be on the account of overall situation,coordination and network operations.With the gradual increase of DG penetration rate and the complex network architecture,traditional distribution network protection models based on three-segment currents are difficult to adapt to such development tendency.Therefore,it is of great significance to study smart and efficient protection measures and feeder automation design schemes.In view of the vigorous advancement of the informatization construction of feeder automation in China,this paper proposes a feeder automation scheme based on distributed intelligent terminals,combined with the new national standard Low-Voltage Ride Through(LVRT)DG fault equivalent model.In the simulation method,the DG modeling based on LVRT is completed,the measured data is integrated,the fault network is designed,the fault status is simulated,and the feasibility is tested.First,the theoretical basis of the LVRT control strategy is studied.Based on the technical standards and network requirements,the fault output characteristics are defined,and a distributed power supply fault model for low voltage ride through technology is established.On the other hand,combining traditional protection theories,the basic fault types and the shortcomings of traditional distribution network protection measures are discussed,and the basic fault characteristics of distributed power grid connection are analyzed.Based on the DG model and basic fault characteristics,the LVRT control strategy distributed power grid fault output characteristics are summarized,which provide the technical requirements for the feeder automation program.Secondly,the feeder automation(FA)scheme based on distributed intelligent terminals is studied.Taking the intelligent terminal as the minimum unit,the network construction method is discussed.Multiple agents are used to partition the feeder and collect the fault information features of the block.On the basis of this,using the variation of the inflow and outflow currents of the block as the failure criteria,regional positioning is performed.Based on the point-to-point communication method of the intelligent terminal,the functions of each terminal unit in the block are determined.A protection scheme using GOOSE rapid communication is established,and fault criteria are established based on the magnitude and phase angle of the fault current to improve protection measures.After the fault was removed,the shuffled frog leaping algorithm was introduced.Based on the actual operating characteristics of the distributed power supply,the distribution network is reconstructed.Finally,fault scenario design and program simulation verification are performed.Based on the actual operation of DG power generation capacity,in the MATLAB simulation environment,combined with LVRT control technology,the DG fault equivalent models are established.The specific fault scenarios are selected to build a high-density distributed power grid-connected distribution network fault network.After faults set,the fault isolation and distribution network reconfiguration simulation are performed.Based on the simulation results of three-phase short-circuit faults,the functional verification of the distributed intelligent feeder automation scheme is performed.The simulation results show that the distributed intelligent feeder automation scheme has good adaptability to the access of high-density distributed power supply.