Ultrahigh frequency partial discharge positioning time delay estimation method

Abstract

The invention discloses an ultrahigh-frequency partial discharge positioning time delay estimation method, which comprises the following steps of: processing a plurality of sample data acquired by an ultrahigh-frequency sensor through correlation-shift-superposition transformation to obtain a representative partial discharge signal waveform, and analyzing the representative partial discharge signal waveform by using the statistical property of a fourth-order cumulant. And the time difference between the two partial discharge signals can be obtained. During correlation-displacement-superposition processing, horizontal shaking and random interference of the obtained partial discharge signal are effectively eliminated, fourth-order cumulant calculation is performed on the basis, Gaussian noise of the signal is suppressed again, so that the signal-to-noise ratio is improved, the noise is effectively eliminated twice, an obtained time delay result is closest to a theoretical value and is very stable, and the method is suitable for large-scale popularization and application. Compared with other extraction algorithms, the method has obvious superiority.

Description

technical field [0001] The invention relates to the technical field of partial discharge location of electric equipment, in particular to a method for estimating time delay of UHF partial discharge location, which belongs to the improvement of time delay estimation algorithm in UHF signal time difference location method of transformer partial discharge source. Background technique [0002] Partial Discharge (PD) is a discharge phenomenon that occurs locally when insulation defects occur inside electrical equipment. Most of the faults of power transformers are caused by partial discharge caused by internal insulation defects, which intensifies and develops under the operating voltage, and eventually causes the failure of the overall insulation performance of the equipment. Ultra High Frequency (UHF) detection technology has the advantages of high sensitivity and strong anti-interference ability, but power transformers are bulky, complex in structure, harsh in electromagnetic ...

AI Technical Summary

Problems solved by technology

Most of the faults of power transformers are caused by the partial discharge generated by internal insulation defects, which intensifies and develops under the operating voltage, and eventually causes the failure of the overall insulation performance of the equipment.

Ultra High Frequency (UHF) detection technology has the advantages of high sensitivity and strong anti-interference ability, but power transformers are bulky, complex in structure, harsh in electromagnetic environment, and the types, positions and numbers of defects in the insulation structure are diverse. How to realize accurate and reliable fault location based on the UHF partial discharge signal is an urgent problem to be solved in the state monitoring of power equipment

In addition, in the calculation process of partial discharge source location, in addition to background noise, sensor response time, rise time of partial discharge current pulse and many other influencing factors, it is difficult to accurately obtain partial discharge single signal time delay. The time difference equation set established by the value wave velocity also affects the accuracy of positioning to a certain extent, resulting in the so-called "multi-level error amplification", which further reduces the positioning accuracy of partial discharge, and even makes it impossible to locate

At the same time, the current positioning algorithm still faces difficulties such as sensitivity to delay errors, easy local convergence or divergence, and slow operation speed.

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