Research On Radial Distribution Network Fault Location Based On Multi-Measurement Information

Electricity supply directly affects people's daily lives.How to improve the quality and reliability of power supply is an important part of meeting people's needs for a better life.As a power supply terminal directly facing power users in the power system,the safe operation of the distribution network is a key step to meet the quality and reliability of power supply.The fault location method of transmission grid has been developed relatively well,and the positioning effect is better.Compared with the power transmission network,the distribution network has many branches,the network topology is complex,and the neutral point of the system is operated with low-current grounding.The fault signal is weak,the high-frequency components in the traveling wave are complex,and the fault feature extraction is more difficult.The method for fault location in power grids cannot be directly used for fault location in distribution networks.Further research is needed on fault location methods in distribution networks.This paper researches the application of traveling wave method in fault location of radial distribution network.First,the principle of traveling wave generation and propagation on the wire is introduced,and the refraction and reflection phenomena of traveling wave are analyzed.The process of extracting fault feature from fault traveling wave is studied: phase-mode transform decoupling and time-frequency analysis to obtain wave head time.The principle of phase mode transformation and three commonly used phase mode transformation matrices are introduced.The Karenbauer transform is used to decouple fault traveling waves,and wavelet transform is used to extract the wave head moment of the decoupled modulus.Secondly,in order to reduce the system investment and maintenance costs,for the complex topology of the distribution network,the FTU optimization configuration scheme was studied.Based on the configuration scheme,a section positioning method based on the D-type traveling wave method is improved.This method constitutes a D-type traveling wave system by designing the FTU device combination strategy to calculate the fault distance,combined with the length of each line of the known topology Determine the section where the fault is located.This method can accurately identify the section where the fault is located,and significantly reduces the amount of calculation compared with before the improvement.Finally,in order to improve the positioning accuracy,a fault location method for distribution network based on multi-spot information is proposed.This method uses weighted aggregation of multi-spot ranging information fusion to determine the location of the fault,which is mainly divided into two parts: based on Single-end ranging method of modulus time difference and multi-point measurement data fusion based on dynamic adjustment of weight.Simulation verification shows that the algorithm meets the expected requirements in terms of measurement accuracy.