基于超高频和超声阵列信号的变压器局放定位方法研究

Location Method for Transformer Partial Discharge Based on UHF and Ultrasonic Array Signals

变压器局部放电的检测与准确定位对于及时发现变压器内部的潜伏性绝缘缺陷、预防事故的发生具有重要意义。分析了现有的局放定位方法,指出超声法具有广泛的应用前景。针对超声法检测灵敏度不高等问题,介绍了一种基于超高频和超声阵列信号的变压器局放定位方法。该方法以超高频信号的接收时刻为基准进行测距,并基于快速子空间算法(FDOA)对超声阵列信号进行波达方向估计,得到局放源的方位信息,进而对其定位。在试验室中搭建了一套完整的试验平台,使用该方法对变压器局部放电进行定位试验,结果表明误差均在10 cm以内。验证了所提方法的有效性与实用性。

Transformer partial discharge （PD） detection and precisely locating is important in finding the insulation defect in a transformer and preventing power system fault of. The paper analyzes existing PD location methods, and proposes the location method for the transformer partial discharge based on UHF and ultrasonic array signals to improve the sensitivity of ultrasonic testing. Firstly, this method takes the receiving time of UHF signal as a reference, getting the time delay of ultrasonic transmission to seek out the space distance between the source and the sensor through sequential relationship. Then,the method orientates with PD＇s ultrasonic array signals based on fast subspace algorithm, getting the location information of PD source and positioning it. The experimental platform for transformer PD locating is built in a laboratory, and the laboratory studies demonstrate that this method has a high accuracy with an error of less than 10 cm as well as effectiveness and practicability.