Study Of Traveling Wave Fault Location For Series Compensated Lines

Due to the contradiction between the economic development of China and the unevendistribution of the primary energy, it will be inevitable for the large distribution network to becharacteristic of ultra-high voltage, long distance and large capacity. The transmissioncapacity of the high-voltage and long-distance transmission line is usually limited by the linestability. The too long line leads to the following problems such as the increase of the networkloss, the uneven distribution of the current, and the worsening of the system stability. Thoughthe introduction of the series compensation capacitor can better tackle the above-mentionedproblems, it changes line parameters accordingly, which makes it difficult to identify the faultinformation of the system and conduct the fault location of the system.In recent years, scholars have conducted a lot of research on the fault location of theseries compensation capacitor and specifically come up with ways of location. However, thesealgorithms, usually based on the power frequency and line parameter, will be accompanied bypseudo roots for computational complexity and heavy calculation. Based on the study andanalysis of fault location algorithm of the series compensation lines, this paper introduces theapplication of the energy ration function to the fault location. Furthermore, the superiority ofsuch way is shown in the fault location in contrast to multi-resolution morphological gradient(MMG).This paper first introduces the traveling wave theory of the transmission line, andexpounds the theory of wavelet transform applied in the digital signal processing and greyvalue morphology theory. For the noise in the high-voltage transmission lines, the author ofthis paper resorts to the theory of wavelet transform and the grey value morphology grads todenoise. By comparing the noise signal processing effect of these two methods, good filteringeffect can be obtained by choosing suitable noise filtering tools for the features of differentnoises.Secondly, in view of the nonlinearity of the MOV, the feasibility of the application of the travelling wave in the fault location of the series compensation lines is verified by analyzingand studying the operating principle of the MOV. The combination of the series compensationcapacitors and the equivalent impedance of the transmission lines lead to the formation of theseries compensation filter, with the function of filtering the high-frequency signal in thecircuit. This paper demonstrates the feasibility of the application of the energy ratio functionalgorithm in the fault location of the series compensation lines by studying the influence ofthe filtering effect on the energy ration function.Finally, the simulation model is established for different series installation locations, faulttypes and fault locations. And the multi-resolution morphological gradient (MMG) and thepower ration method are respectively adopted to conduct simulation for the fault in differentsituations. By changing the different sampling frequency, transition resistance, fault switchingAngle, phase Angle difference on both ends of the line, and series compensation degree, theimpact on the fault location results can be analyzed and the robustness of the range algorithmcan be studied.