变电站局部放电特高频信号时延的双谱估计算法

Time-delay Estimation Algorithm of Partial Discharge UHF Signals in Substation Based on Bispectrum

时延估计是基于时间差法的变电站局部放电空间定位算法的基础,也是决定定位精度的关键。阐述了双谱时延估计的理论基础,给出了参数化双谱时延估计算法的数值实现步骤。利用双指数振荡衰减函数模拟局部放电特高频信号,并加入高斯噪声及定频信号干扰,计算两路模拟信号之间的时延,验证了该算法的准确性。最后针对基于天线阵列的变电站局放定位系统,现场实测4路特高频电磁波信号,基于所提出的时延估计算法计算不同位置的天线接收到特高频信号的时延,并将该时延序列估算出局部放电源的空间位置,从而验证了该算法的有效性和实用性。

Time delay estimation is the basis of the localization algorithm for partial discharge（PD） based on time difference in substation, and it is the key to the localization accuracy. Theoretical basis ofbispectrum time delay estimation was described, and the computational numerical implementation steps of the parametric bispectrum time estimation algorithm was given. In the simulation test, simulated signals of the UHF caused by partial discharge, which were simulated by double exponential oscillation decay function, and noised by Gaussion progress and period signals, were used for verifying the accuracy of this algorithm. Finally the algorithm was used to calculate time delay of the field PD signals, and the sequence of the delay was applied to substation PD localization based on antenna array. The PD source location could be estimated, so the effectiveness and practicality of the algorithm has been verified.