Traveling Wave Location Of Grounding Fault And Optimal Configuration Of Traveling Wave Device In Distribution Network

The distribution network has many branches and complex structure,when a ground fault of distribution network occurs,if the location of the fault can not be found in time and accurately,the fault can not be eliminated as soon as possible,this will directly affect the user’s electricity safety and bring economic losses.Therefore,the accurate location of great significance for stable and economic operation of power distribution network and improving power quality.In order to reduce the pressure of urban traffic,the distribution network of mixed lines in cities is increasing,and increases the difficulty of fault location in distribution network.The location method of traveling wave has the characteristic of not being affected by system parameters,operation mode and transition resistance.So this method has been applied more widely in fault location of transmission network.successfully.In comparison with the transmission network,distribution network has many branches and complex structure,which is likely to interfere with traveling waves,and distribution network has more terminals,this results in high cost of installing traveling wave positioning device,so the application of traveling wave location in distribution network is limited.Based on the single-phase grounding fault,this paper mainly studies the traveling wave positioning method and the optimal configuration of the traveling wave device,and is devoted to improving the practical value of the traveling wave positioning in the distribution networkAiming at the problem of low positioning accuracy in noisy environment,a new traveling wave location method based on moduli transmission time difference under noise is proposed.The wavelet transform modulus maxima principle is used to calibrate the arrival time of the zero line mode traveling wave with comprehensive wavelet coefficient.Based on the fitting curve of zero mode real time wave velocity and fault distance,an iterative formula is established to complete the ranging.The final location results are obtained by integrating the multi terminal ranging results.Simulation results show that the proposed method still has high positioning accuracy and stability when SNR reaches 20 dB.Due to the inconsistency of the traveling wave velocity of the mixed distribution network,the location error is large,so the fault location method of the hybrid distribution network based on the section information system is established.At first,based on the hybrid distribution network at both ends,a range formula based on the time difference between the two ends of the fault wave is established,then on the basis of the simple T type mixed circuit,a section information table is established to locate the section.According to the nature of the fault location,the precise positioning is completed.The last,the construction method and calling rules of section information system based on Multistage T-type line in complex distribution network are put forward to complete precise positioning.Simulation results show that the algorithm is highly practical and effective,and the process is relatively simple,and has certain engineering practice value.To improve the economy of traveling wave positioning in distribution network,a method of optimal allocation of traveling wave location device based on single ended method is proposed.First of all,use the graph theory to stratify the distribution network of target,and define the ordinary independent branch and the symmetric independent branch.Then the fault location of the simple T type line is deeply studied,and the optimal allocation method of the simple T type line is obtained by backstepping method: there is no location device on the regular independent branch and an arbitrary symmetrical branch branch.After optimizing the two examples,the number of positioning devices is reduced by 40% and 50% respectively.Setting up grounding fault to simulate,and the location result is proved to be excellent.The accuracy of localization is equal,so it is not affected by transient resistance and initial fault angle.