基于复合阵列传感器的应用射线追迹反推变压器中局部放电源

Applying Ray Tracing to Backstep Partial Discharge Sources in Transformers Based on Combined Arrays

研制了将25阵元十字型超声阵列和2×2阵元特高频阵列共同构成复合阵列传感器。研究了适用于复合阵列传感器的定位算法。将特高频阵列虚拟扩展为13阵元,超声阵列虚拟扩展为193阵元。利用扩展的特高频阵列由双边相关变换算法来预估局部放电源的方位,根据预估结果再对扩展的超声阵列使用旋转信号子空间算法进行精确定向。为了提高单一阵列在局部放电定位中定向成功率和精度,以特高频信号为例,利用基于几何光学与一致性几何绕射理论的射线追迹法研究了对局部放电辐射电磁波轨迹的反演。在变压器模型中的局部放电定位试验表明,基于复合阵列传感器的定位算法对局部放电产生的宽带信号有良好的适应性,以及对局部放电辐射电磁波的追迹反演使定位精确度与成功率均远大于单一阵列的结果,发挥了特高频阵列灵敏度高而超声阵列定向精确度高的优点。

The combined array sensor was studied which consists of a cross-shaped ultrasonic array with 25 elements and an UHF array with 2 x 2 elements. Algorithms for location based on the combined array were studied, which achieved the virtual expansion of 193 and 13 elements of the two arrays respectively. Two-sided correlation transformation （TCT） based on the UHF array was employed to estimate the PD＇s direction, and then the rotated signal sub-space （RSS） based on ultrasonic was used for accurate direction. To improve the success rate and accuracy of a single array in PD positioning, taking the UHF signal as example, the ray tracing technique based on geometrical optics （GO） and uniform geometric diffraction （UTD） was used to study the inversion of the electromagnetic wave trajectory of PD. The experiments of partial discharge positioning in the transformer model indicates that the position algorithm based on the combined array sensor has a good adaptability to the wideband signal generated by PD and the tracing inversion of the PD radiation electromagnetic wave makes the position accuracy and the success rate much greater than the results of a single array, namely the combined array demonstrates the advantages of the high sensitivity of UHF arrays and the high accuracy of ultrasonic arrays.