基于暂态对地电压和超声阵列信号的变压器局放定位方法

变压器局部放电的快速、准确定位对于及时排除故障隐患,保障电力系统的安全稳定运行具有重要作用,论文介绍了一种基于暂态对地电压和超声阵列信号的变压器局放定位方法。该方法首先以接收到暂态对地电压(TEV)信号的时刻为基准进行测距,并基于改进FastDOA算法对超声阵列信号进行测向,再根据测距和测向结果实现定位。改进FastDOA算法在传统FastDOA的基础上构造不同孔径的虚拟阵列,并对各虚拟阵列得到的估计谱值加权平均以减小伪峰的影响,可有效提高测向精度。在此基础之上,利用Matlab对基于改进FastDOA的测向算法以及超声阵列传感器结构参数的优化设计进行了仿真分析。最后研制了相应的传感器并搭建了变压器局部放电超声阵列定位实验平台,开展实验研究,结果验证了所提方法的有效性。

Study of Partial Discharge Locating Method in Transformer Based on Transient Earth Voltage and Ultrasonic Array Signals

The quick and precise locating of partial discharge is important in eliminating the hidden faults promptly and ensuring the safety and stability of the power system.In this paper,the existing methods of partial discharge(PD) locating are analyzed at first,and then a PD locating method based on transient earth voltage and ultrasonic array signals in transformer is introduced,which regards the time point of signal detected by the transient earth voltage(TEV) sensor as the time benchmark to calculate the distance between PD source and ultrasonic sensor and orientate the PD source based on the modified fast direction of arrival(FastDOA) algorithm by ultrasonic array signals.This algorithm expands a real sensor array into several virtual arrays of different aperture to enhance the resolution,and averages the spatial spectrum of the virtual arrays to restrain the spurious peaks.Then the orientation based on the modified FastDOA algorithm and the design optimization of the ultrasonic array sensor is simulated with Matlab.The corresponding sensor is developed and the PD locating experimental platform in transformer is built at last.The experimental results verify the effectiveness of the proposed method.