基于插值相关法的局部放电特高频脉冲信号时延估计

Time-delay Estimation of Partial Discharge UHF Pulse Signals Based on Interpolation Cross-relation Algorithm

为了提高用于特高频局部放电检测与定位所需的多元传感器阵列间的信号时延精度和降低特高频检测系统成本,提出了一种先对低采样频率采集所得的局部放电特高频脉冲信号特征区域进行三次样条插值,后利用广义相关法估计信号时延的新方法。仿真实验研究和模拟实验结果表明:对于满足采样定理采集所得的低采样频率局部放电信号,该方法比传统广义相关法对信号时延的估计精度更高,可有效减小实际时差为采样间隔非整数倍所带来的时延误差;信号两点间插值数为4时,算法最优,时延误差可控制在半个系统采样间隔以内。

In order to improve the precision of time-delays calculated from a multi-element ultra-high frequency （UHF） sensor array and reduce the cost of partial discharge detection system, we put forward a new method to estimate the time-delay. This method interpolates some values into the feature area of UHF signal sampled at a low sample rate based on interpolation cross-relation algorithm and then uses cross-correlation method to estimate the time-delay. Through si- mulation tests and experimental results, conclusions are obtained as follows. Firstly, compared with traditional cross-correlation method, the new method can effectively narrow the error generated by limit of the system sample rate, especially when the real time-delay is not a integer times of sampling interval. Moreover, when the number of interpolat- ing value between two original signal points is four, the method becomes optimal and can narrow the errors below a half sample interval.