Study On Single-Phase-To-Ground Fault Location In Distribution Network Based On Traveling Wave

A detailed comparison and analysis is made in this paper on characteristics of fivetraditional fault location methods based on traveling wave, and thus pointing out their commondeficiency of ignoring the influence of traveling wave speed. Therefore, two improved schemesare proposed in this paper. Regarding transmission lines without branch, an improved doubleterminal method is proposed, which makes full use of the reflection and refraction informationof fault transient traveling wave. In this way, the influence of traveling wave speed can belimited, and thus improving the precision of fault location. Regarding transmission lines withbranch, a novel scheme is also presented, which is building T matrix (Time-judge matrix)around branch node and D matrix (Fault-judge matrix) as criterion. Therefore, the problem offault branch distinguishing can be solved, and the fault distance can be determined by means ofD-traveling wave.Fault information in transient traveling wave is extracted by wavelet transform, whichenjoys the advantages of local time-frequency characteristics and an outstanding ability toanalyze the singularity of non-stationary signal. Considering the superiority of lifting algorithm(simple principle and fast computation), a lifting scheme of Haar wavelet is deduced in thepaper. The scheme is then successfully applied to detecting singular point of transient travelingwave. In this way, the efficiency of fault location algorithm is greatly improved.Finally, in the model of110kV Zhongcao substation built in ATP-EMTP, a large number ofexperiments are done on transmission lines with and without branch. In the experiments, bysetting different values to relevant parameters (fault distance, transition resistance, simulationtime, etc.), the feasibility of the two fault location schemes proposed in this paper is verified.The result of the experiments demonstrates that the two schemes are not only able to locatefault points rapidly and accurately, but also more precise and reliable than the traditional ones.