Research And Application Of Algorithms Based On FTU Distribution Network Fault Location And Isolation

With the rapid development of society,people's demand for electricity is increasing,and at the same time,higher requirements are placed on the distribution network in terms of power supply reliability and power supply quality.As one of the main tasks of distribution network automation,fault isolation can timely and accurately identify fault areas and quickly isolate faults,thus improving the reliability of power supply.Distribution automation is an important part of the power system.With the development and reform of the power system,distribution automation will face greater challenges.Distribution network fault location and isolation as the core content of distribution automation,its function realization and improvement will play a decisive role in the entire distribution automation levelThe distribution network equipment is complex,the users are numerous,the coverage is wide,the geographical situation is varied,so it takes a long time to find the fault point when the fault occurs.Distribution network automation is an important means to reduce the area of power failure and improve the reliability of power supply.A large number of FTU and other field monitoring terminals are used in the distribution system,which provides the premise and guarantee for the rapid and accurate realization of the feeder automation function of the distribution system.Scientific and effective fault location method enables the system to quickly and accurately find the fault area and restore the power supply in the non fault area when the distribution network fails.The fault location of distribution network is a hot spot of power industry research at home and abroad,which has extremely important theoretical value and engineering practical valueDue to the complex and changeable topology of distribution network,this paper adopts the ring structure of modern power grid hand-in-hand,which has the characteristics of normal closed-loop structure,open-loop operation and radial power supply to users.After the fault occurs in the distribution network,the FTU installed at each section switch will detect the fault information(such as fault current)and upload it to the SCADA system of the control center.After the comprehensive analysis of the fault diagnosis algorithm,the system can identify the location of the fault point,realize the fault location,and issue the command to remotely control the FTU to disconnect the section switches on both sides of the fault point,and then isolate the fault area.Based on the research and analysis of distribution network model,this paper conducts an in-depth study on the optimal placement algorithm of FTU(Feeder Terminal Unit).By fully excavating the characteristics of distribution network topology,a fault location algorithm based on distribution network directional stratification model is proposed.This algorithm can clearly represent the stratification of each vertex in distribution network,and carry out topology description and fault location.It is also suitable for general fault areas(areas with contacts)and general fault district(general district without contacts).Combined with the network characteristics of distribution network,by optimizing the arrangement of FTU in distribution network,the accuracy of the state estimation of active distribution network can be guaranteed,and the effective isolation of the fault area can be achieved through FTU.The main contents are as follows:This paper first introduces the characteristics of the distribution network,analyzes the common line faults of the distribution network,and builds a simplified model of the distribution network,including the model construction of distribution lines,distribution transformers and distribution capacitors.Secondly,the function of FTU is introduced in detail.The network state and fault blackout loss are estimated and analyzed.An algorithm based on FTU is proposed.On this basis,the matrix algorithm of fault location in distribution network and the fault diagnosis method based on BP neural network are researched and analyzed.At the same time,the isolation scheme of fault area of power distribution network based on simplified model is proposed.Finally,the effectiveness of the fault location and isolation algorithm used in this paper is verified by simulation.