基于定向准确度的局部放电超声阵列传感器声学性能定量评价

A Quantitative Evaluation Method for Acoustic Performances of Partial Discharge's Ultrasonic Array Sensors

声学性能良好的超声阵列传感器是确保局部放电检测成功率和定位精度的基础,目前国内外尚未开展局部放电超声阵列传感器声学性能的定量评价研究。该文提出一种基于定向准确度参数的局部放电超声阵列传感器声学性能定量评价方法。分析平面方形阵和均匀圆环阵的指向性函数及其分布,推导得到阵列传感器的定向准确度与指向性函数的关系,并采用定向准确度作为评价指标,对两种阵列结构的声学性能进行量化评价。应用FastDOA算法,仿真研究不同阵元个数时,两种阵列结构的窄带局部放电超声信号测向精度与定向准确度之间的变化规律,结果表明,同一阵列形式,局部放电超声阵列传感器定向准确度参数值越小,测向精度越高,表明声学性能越好;相同阵元个数下,均匀圆环阵的定向准确度值较方阵要小,表明圆阵声学性能更优。最后,采用自行设计研制的3×3方阵与9元均匀圆环阵在实验室采集同一宽带局部放电超声信号,并应用同一聚焦、测向算法进行局部放电超声信号的测向研究,实验结果验证了该文方法的正确性。

The partial discharge’s ultrasonic array sensor（PD sensor） with good acoustic performances is the basis of PD detection and location. There is no quantitative evaluation method for PD sensor’s acoustic performances at present. This paper proposed a quantitative evaluation method for acoustic performances of the PD sensor. Firstly, the directivity diagram of the square array and uniform circular array was researched qualitatively, then the directive accuracy was chosen as the evaluation index to evaluate the acoustic performances of the two arrays; Secondly, the DOA（direction of arrival） precision of narrow-band signals of the above arrays for different element numbers were compared by simulations, the results show： the smaller the evaluation value is, the higher accuracy DOA will get, if the array sensors’ structure is the same. The evaluation value of the uniform circular array is smaller than the square array if the array sensors’ element number is the same, which shows that the circular array has the better acoustic performances. At last, several experiments using a 3？3 square array and a uniform circular array with 9 elements were done in the lab, and the ultrasonic array signals were processed by the same algorithm, the results prove the correctness of the proposed method.