| Transmission line fault is the main factor affecting the safe and stable operation of the power grid.The quick search after transmission line malfunction can help to improve power supply and reduce losses effectively.At present,the fault recorders are installed in transmission lines of 110 k V and above,and all transmission lines of 220 k V and above together with some transmission lines of 110 k V are equipped with traveling wave locating devices.However,there are still problems in locating faults precisely.And the results of traveling wave locating devices and fault recorders have not been integrated and utilized effectively.The fault locating methods based on frequency parameters of fault recorders and high frequency transient data acquisition of traveling wave locating devices are the main ways for transmission line malfunction location.There are different principles and advantages between them.The fault location principle of the fault recorder relies on the measurement of impedance calculation of the acquired signal,which is of great stability.However,the location may be affected by the transition resistance and the impedance of the back side of the system.The traveling wave locating method relies on the propagation law of the transient distortion signal generated at the initial moment of the fault.It depends on the calibration and identification of the wave-head in principle.And it can be easily disturbed and starts frequently,but is not limited by system operation mode and transition resistance.The fault recorders and traveling wave locating devices have been in operation in the transformer substation as two independent devices for a long time,and they have certain repeatability in function.We tend to conduct research on the integration of fault recorder and traveling wave fault location from the perspective of traveling wave data filtering and optimizing the wave-head calibration in this study.The full text is divided into five chapters.The first chapter is the introduction part,which analyzes the current research progress and achievements of fault location and traveling wave locating technology.The second chapter analyzes the principle of traveling wave locating technology,and describes the refraction and reflection path along the transmission line and the traveling wave dispersion effect under the multi-conductor transmission system.The third chapter proposes a function verification method of integrated fault recording device,which specifically analyzes the reasons for the devices wrong start-up due to filter circuit and current transformer of high frequency part acquisition and power frequency part acquisition in the integrated fault recording device.According to the analysis results,we propose a feature sequence extraction method based on K-means and Gaussian Mixture Model(GMM)algorithm.Finally,Dynamic Time Warping(DTW)algorithm is used to filter the fault and non-fault travelling wave data effectively.The fourth chapter analyzes the method of wave-head calibration for traveling wave,and improves its existing defect of inaccuracy.We propose a wave-head calibration method for traveling wave based on the Line Segment Detector(LSD),and use the wave-head double calibration method formed by wavelet modulus maxima and LSD to improve the calibration accuracy.The reliability and accuracy of the calibration method are verified by Power Systems Computer Aided Design(PSCAD/EMTDC)simulation software and the comparison between the theoretical ranging results and the measured fault distance.Our research can promote the popularization and application of the integrated fault recording device,and the fault location device formed by different principles will be further improved in terms of reliability and accuracy. |
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