Cross-shaped ultrasonic array sensor and method for transformer partial discharge localization

Abstract

The invention discloses a cruciform ultrasound array sensor and method for positioning transformer partial discharge. The ultrasound array sensors are arranged in a cross way and at equal intervals; the number of piezoelectric sensors is 5 to 300; ultra-high frequency sensors are located around the cruciform ultrasound array sensor; the outside of the sensor is a metal shield and the bottom surface of the sensor is a matching layer. The method comprises the following steps of: virtual expanding the cruciform array by high-order cumulant technology; estimating direction of the expanded virtualarray by a spatial spectrum estimation algorithm; and then synthesizing ultrasound beam of at the estimated direction, combined with electric pulse or ultra-high frequency electromagnetic signal produced by partial discharge, obtaining propagation delay of the ultrasonic wave in the transformer and further positioning the transformer partial discharge. The subsequent hardware circuits of the sensor can be greatly decreased, the production cost can be saved; moreover, Gaussian colour noise can be effectively inhibited, and the practicability of array technology in the partial discharge detection field can be achieved conveniently.

Description

technical field [0001] The invention belongs to the field of high-voltage equipment and test technology, 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 location of the partial discharge source can be obtained. The application of array technology to locate partial discharge is a new method that has emerged in recent years. This method has high positioning accuracy and can locate multiple partial discharge sources that occur simultaneously. [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. In particular, the use of ultra-high frequency signals of parti...

AI Technical Summary

Problems solved by technology

In addition, 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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