Research On Fault Location Of Distribution Network Based On HHT

The distribution network in China with small current grounding,when single-phase grounding fault occurred in distribution line,the fault phase voltage is decreased,the system can run with fault of 1—2 hours,in order to ensure the reliability of power supply,as soon as possible to find out the fault and to remove is needed.At present,the method used in the transmission network is relatively mature,and the positioning effect is good.So most of the existing research methods are applied to the fault location of transmission network.But the distribution network and transmission network are different,such as the distribution network grounding,the structure of distribution network,and a lower voltage distribution line,so the signal of fault is weak,the signal in the high frequency component complex,fault feature extraction is difficult,so we need adopted an effective location method.In this paper,the following parts of the fault location of distribution network are completed:The present several main principle of traveling wave fault location are summarized,show that the single and double side traveling wave for mixed line fault location with complex structure.Analysis of the propagation characteristics of distribution network transient traveling wave characteristics in the event of failure and the traveling wave in the distribution line,from the principle that the traveling wave fault location method is feasible in the transmission line fault location in distribution line.In order to extract the fault characteristics of fault transient traveling wave signal,firstly,the fault traveling wave signal is transformed by Karenbauer and the HHT transform is used to analyze the arrival time of the fault wave head.The HHT transform is divided into two processes: EMD decomposition and HT transform.Firstly,the modal components are obtained by EMD decomposition,and then the spectrum of each mode function is obtained by HT transform.The method of local feature scale extension is used to improve the signal boundary distortion in the process.A FTU configuration method based on fault location of distribution network is proposed.This method needs to select the main line of the distribution network,and then determine the complex branch lines and simple branch lines,according to the selection of the main line configuration FTU.The simulation results show that the proposed scheme can distinguish all the faults in the fault area under the condition of excluding all the false fault points,and the relative traveling wave two terminal location method can greatly reduce the number of FTU and reduce the investment.In this paper,the FTU configuration scheme is proposed to locate the fault of distribution network,and the fault location and fault location are mainly included in the positioning process.Firstly,the fault location is determined according to the time difference between the two ends of the FTU,and then the fault distance is calculated by the corresponding traveling wave ranging algorithm.The simulation of the FTU configuration method proposed in this paper and the traveling wave fault location method,the radial distribution line of IEEE14 and IEEE33 bus,the simulation results show that the distribution network configuration method proposed in this paper and the corresponding method of fault location for distribution network fault location.