Research On Fault Location Of Distribution Network Based On Multi-point Monitoring

With the continuous promotion of urban and rural power network upgrading and transformation projects,the scale of distribution network construction is expanding,and the fault location technology of distribution lines is also developing rapidly.Distribution network belongs to the end of power system and is directly oriented to users.It is an important public infrastructure serving people's livelihood.After line failure,it will seriously affect the safe and stable operation of power grid,accelerate the insulation aging of power facilities,bum down equipment for a long time,and even more serious,it will cause instantaneous collapse of power grid,directly lead to large-scale blackouts in key areas,and cause huge losses to national economy and peopled lives.Great losses,even endanger personal safety.Therefore,it is of great significance to realize efficient and accurate fault location of distribution network,improve reliability and stability of power supply for fault location of distribution network,and create a good power supply and consumption environment.This dissertation introduces the main characteristics and fault diagnosis theory of distribution network in China,compares and analyses various methods of fault location based on traveling wave principle.According to the shortcomings of traditional traveling wave fault location method,a fault location method for distribution network based on multi-point monitoring is proposed,and its accuracy for improving fault location accuracy is verified by simulation checking and result evaluation.With reliability,the design scheme of distribution line fault monitoring system is given,and the monitoring device is developed and tested.The contents of this dissertation are as follows:(1)Introduce the development status and main characteristics of distribution network in China,and analyze the practical problems of fault location in distribution network.(2)The theory of power line fault diagnosis is studied,including the generation principle of fault traveling wave,propagation characteristics and fault transient signal processing methods,to verify the effectiveness and convenience of HHT transformation in the application of fault location transient signal processing in distribution network.(3)Analyzing the shortcomings of traditional single-ended,double-ended and three-ended fault location methods,a new method of fault location for distribution network based on multi-point monitoring is proposed.The HHT transform is used to obtain the instantaneous frequency-time diagram of traveling wave,screen the initial traveling wave time value monitored by multi-point monitoring device,and carry out the location checking.(4)The single-phase-to-ground fault simulation of multi-dominant power lines is carried out with the help of MATLAB simulation software,and the obtained data are analyzed and evaluated.It is verified that the proposed fault location method based on multi-point monitoring is obviously superior to the traditional traveling wave fault location method,and the location accuracy is significantly improved.(5)Design the software and hardware scheme of multi-point monitoring fault location system,study the working principle of current transformer,digital signal processor and data communication module,explain the field application of multi-point monitoring device,and prove the practicability and reliability of multi-point monitoring fault location method through experimental diagnosis results.