L-shaped ultrasonic array sensor and method thereof for partial discharge location of transformer

Abstract

The invention discloses an L-shaped ultrasonic array sensor for partial discharge location of a transformer. The ultrasonic array sensors are arranged in an L-shaped manner at equal intervals; the number of array elements (piezoelectric sensors) is 3-300; and an ultrahigh-frequency sensor is located on a right-angle inner side formed by the L-shaped ultrasonic array, shielded by metal around and provided with a matching layer on the bottom surface. The L-shaped array is subjected to virtual expansion by use of higher order cumulant technology; the expanded virtual array is subjected to direction estimation by a spatial spectrum estimation algorithm, then wave beam synthesis is performed on the estimated direction; and with assist of the electric impulse or ultrahigh-frequency electromagnetic wave signal generated by the partial discharge, the propagation delay of ultrasonic wave in transformer can be obtained so as to perform location. The follow-up hardware circuits of the sensor can be greatly reduced, and the manufacturing cost is saved; and moreover, the Gaussian color noise can be effectively inhibited, being beneficial to the practical use of array technology in the field of partial discharge detection.

Description

technical field [0001] The invention belongs to the technical field of high-voltage equipment and testing, in particular to the detection and positioning technology of partial discharge inside a power transformer. Background technique [0002] Partial discharge will produce electromagnetic waves, sound, light, heat and other physical and chemical phenomena. According to the analysis and processing of these quantities, the position of the partial discharge source can be obtained. The application of array technology to localize partial discharge is an emerging method in recent years. This method has high localization accuracy and can locate multiple simultaneous partial discharge sources. [0003] However, the current research is generally based on array sensors with rectangular surfaces. To ensure that the array has a sharp enough directionality, the number of array elements needs to be large. Especially using the ultra-high frequency signal of partial discharge for detectio...

AI Technical Summary

Problems solved by technology

In addition, from a structural point of view, the ultrasonic array with a rectangular surface also brings difficulties to the arrangement between it and the UHF (array).

These all lead to a large cross-sectional area of ​​the (composite) array sensor, and subsequent hardware circuits are bulky and costly

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