Research Of Fault Location In Distribution Network Based On Correlation Analysis For Transient Power

From the significance of fault location for distribution network, it discussed the study method and merits or drawbacks of every method, based on the analysed carefully the single-phase to ground fault characteristics of small current to ground system, the author utilized the Kelunbeier transform to obtain the mode components of single-phase to ground fault, and the transform could eliminate the phenomena of electromagnetic coupling existed in three-phase transmission lines. In the paper, the author utilized the subtraction of full-cycle to pick up the zero-mode fault components, and discussed the application of correlation theory into the signal detection. Based on the analysis and discussion above, the author proposed a new fault location method that utilized the transient zero-mode power for small current to ground system. The method takes advantage of the features that the transient zero-mode power of two detection points is highly similar at the upstream or downstream of fault location, and the value of correlation coefficient is close to 1, while the waveforms of both sides are quite different at the fault location, and the value is small, comparing the correlation coefficient value calculated with two adjacent detection points with the threshold. If the value is larger than threshold, the section is judged as non-fault, otherwise, it is judged as fault section. According to calculate the maximum of correlation coefficient to avoid the calculation error caused by the data acquired with non-synchronization. In the paper, it introduced the proportion factor of correlation coefficient to evaluate better the advantages and disadvantages of author's method and reference [30]'s method, and evaluated the two method when only consider the threshold allowance, it obtained the best work space of the two methods. Besides, according to the simulation, it got that the power method have good performance when the fault occurred in the end of line and have a larger resistance. Finally, the author made a large number of simulation of single-phase to ground fault for small current to ground system when the different voltage initialization angle and different transition resistance, it found that the author's method can determine effectively the fault section by the correlation coefficient calculated when isolated neutral system or suppression coil to ground system. In addition, the method adopted in the paper is simple in theory and useful in engineering practice.