局部放电定向超声阵列Dir-MUSIC测向算法仿真

Simulation of Dir-MUSIC Direction-Finding Algorithm for Partial Discharge Direction-Finding Ultrasonic Array

超声波检测方法在电力设备绝缘状态检测定位中应用广泛。针对局部放电超声测向MUSIC算法存在的采样率要求高、计算复杂度大等不足,提出基于定向超声阵列信号强度信息的定向多重信号分类(directional multiple signal classification,Dir-MUSIC)算法。在阐述该算法理论模型和应用条件基础上,针对均匀圆盘超声阵列,仿真研究了不同增益方向图主瓣宽度、不同信噪比条件下Dir-MUSIC算法的测向精度。仿真结果表明8阵元阵列在-5 dB信噪比、方向图主瓣宽度为90°~120°时测向精度最高,均方根误差小于2°。最后基于研制的微型机电系统麦克风(microelectro-mechanical system,MEMS)定向超声阵列进行了测向试验,结果表明8阵元圆盘超声阵列测向均方根误差最小为2.76°,测向标准差最小为2.72°,验证了Dir-MUSIC算法的有效性与准确性。

The ultrasonic testing method is widely used in the detection and positioning of insulation status of power equipment.The directional MUSIC(Dir-MUSIC) direction-finding algorithm based on direction-finding ultrasonic array signal strength information is proposed to overcome the shortcomings of MUSIC algorithm for partial discharge ultrasonic direction-finding,such as high sampling rate requirements and large computational complexity.On the basis of elaborating on the theoretical model and application conditions of the algorithm,the paper simulates and studies the direction-finding accuracy of the Dir-MUSIC algorithm under different gain pattern main lobe width and signal-to-noise ratio conditions for a uniform disc ultrasonic array.The simulation results show that the 8-element array has the highest direction-finding accuracy at a signal-to-noise ratio of-5 dB and a main lobe width of 90 °~120 °,with a root mean square error of less than 2 °.Finally,a direction-finding experiment is conducted based on the developed MEMS direction-finding ultrasound array.The results show that the root mean square error of direction-finding for the 8-element disc ultrasound array is the minimum of 2.76 °,and the standard deviation of direction-finding is the minimum of 2.72 °,which verify the effectiveness and accuracy of the Dir-MUSIC algorithm.