Double-end distance measurement method for improving wavelet transform based on windowing

Abstract

The invention discloses a double-end distance measurement method for improving wavelet transform based on windowing. The double-end distance measurement method comprises the following steps of: 1, sampling, namely sampling a failed traveling wave current signal f(t) received by the end m of a bus, and converting the failed traveling wave current signal f(t) into a dispersion function f(n delta t); 2, windowing, namely multiplying a dispersed time sequence f(n delta t) with a window function wN(t); 3, cracking for improving wavelet transform, namely partitioning a signal [fN(k), k belongs to Z] into an even-numbered sequence fe(k) and an odd-numbered sequence fo(k) which are related with each other; 4, forecasting for improving wavelet transform, namely forecasting the odd-numbered sequence fo(k) by the even-numbered sequence fe(k), and defining a forecasting error as a detail signal; 5, updating for improving the wavelet transform; 6, searching a modulus maximum from the detail signal, wherein a transverse coordinate corresponding to the modulus maximum is a moment when a wave head reaches the end m; 7, searching the moment when the wave head reaches the end m from the traveling wave signal at the end n of the bus; and 8, calculating a distance from a failed point to the end m of the bus. According to the double-end distance measurement method, the distance measurement precision can be improved, and the calculation speed can be further increased, so that the calculation time and the time for finding the fault point are shortened.

Description

technical field [0001] The invention relates to a double-terminal ranging method based on windowed lifting wavelet transform, which can be used in a transmission line fault ranging device. Background technique [0002] Double-ended ranging method (see figure 1 ) is the identification of traveling wave heads. The conventional traveling wave pulse detection method realizes the detection by comparing whether the current traveling wave signal crosses the threshold value, which has poor anti-interference ability, and it is difficult to accurately determine the moment when the front edge of the current traveling wave arrives; the derivative method and the ratio method hope to reflect the signal through its rate of change The sudden change of the wavelet transform can achieve the purpose of identifying the head of the traveling wave, but because it is easy to amplify some high-frequency components, the anti-interference ability is not strong, and it is difficult to be applied in p...

AI Technical Summary

Problems solved by technology

The conventional traveling wave pulse detection method realizes the detection by comparing whether the current traveling wave signal crosses the threshold value, which has poor anti-interference ability, and it is difficult to accurately determine the moment when the front edge of the current traveling wave arrives; the derivative method and the ratio method hope to reflect the signal through its rate of change The sudden change of the wavelet transform can achieve the purpose of identifying the head of the traveling wave, but because it is easy to amplify some high-frequency components, the anti-interference ability is not strong, and it is difficult to be applied in practice; the traditional wavelet transform is not only complicated to construct wavelet functions, but also has a large amount of calculation. , large storage space consumption and floating-point calculation; the lifting method directly completes the in-situ calculation in the time domain, so it has the characteristics of saving memory, small calculation amount, and fast speed.

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