基于互相关信息积累的非周期微弱局部放电源探测方法

Aperiodic Weak Partial Discharge Source Detection Based on Accumulation of Cross Correlation Estimation Information

基于外置接收天线的非接触式测试方法在局部放电探测中已得到广泛关注,但其探测距离还有待进一步提升。针对远距离探测中实测局放信号信噪比较低的情况,提出了一种基于双通道测试和互相关信息积累的处理思路,通过将非周期微弱信号的检测问题转化为周期性时延参数估计的检测问题,可间接实现微弱放电信息的长时间能量积累。通过仿真分析和实验测试对该方法的可行性进行了初步验证,结果表明:在低信噪比条件下,利用互相关信息积累可有效抑制噪声干扰的影响,且其噪声抑制能力随积累次数的增加而增强;在同等测试条件下,利用互相关信息积累对局放时延参数估计的准确率明显高于单次观测数据的估计结果,有利于提高现有多天线时差定位系统对局部放电源的远距离探测能力。

The non-contact detection technology based on electromagnetic radiation signal by using external antenna is focused on in location of partial discharge source. However, because of the signal attenuation and the background noise and inference, the signal to noise ratio （SNR） of the mesured partial discharge signal often decreases obviously when the detection distance increases. Therefore, in order to improve the remote detection performance of the non-contact method, we proposed an accumulation method based on double antennas measurement and cross-correlation estimation information, in which the detection of aperiodic weak partial discharge signal was translated to the estimation of periodic time delay parameters, thus the long time accmulation method could be applied to detection and location of the partial discharge source. The simulation and experiment anlaysis were conducted to test its feasibility.The results show that, with the low SNR, the accmulation of cross correlation estimation information can restrain the influence from noise and interference effectively, and its detection performance improves as the accumulation times increase; the accuracy rate of the time delay estimation with cross correlation information accmulation is higher than that without accmulation for the partial discharge on the same conditions. So, this accmulation method can be used for the time difference of arrival （TDOA） system to improve its remote detection performance for the partical discharge source.