【摘要】 基于特高频天线阵列的敞开式变电站局部放电测向系统已获得应用,但该系统的阵列尺寸过大,给巡检带来不便。为缩小阵列尺寸,空间谱估计被应用于局部放电测向系统。鉴于空间谱估计算法种类众多,且不同算法的测向性能受信号的信噪比、入射方向等因素的影响程度有所不同,故需研究适用于变电站站域局部放电空间谱估计算法的选择问题。该文建立局部放电仿真系统,通过改变阵元数目、信噪比和入射方位角等参数,比较双边相关变换(TCT)、旋转信号子空间和信号子空间变换等宽带聚焦算法的性能,以及多重信号分类、求根-多重信号分类、旋转不变子空间、加权子空间拟合等窄带测向算法的测向精度。仿真结果表明,双边相关变换算法运算速度最快,有效测向范围最宽,在信噪比较高时拥有最高的测向精度;求根-多重信号分类(RootMUSIC)算法在小阵元数目条件下测向误差最小,抑制噪声的能力较强,运算时间较短。实验结果表明,采用双边相关变换算法和求根-多重信号分类算法的局部放电测向系统,方位角测向偏差和标准差分别小于3.2°和2.9°,具有较好的测向性能。更多还原

【Abstract】 The partial discharge(PD) direction finding system based on ultra-high frequency array has been tried to apply in air-insulted substation nowadays. However, the size of antenna array is too large that is not convenient for onsite application. To re duce the array size, high-resolution direction finding and focusing algorithm are used in the direction finding system. In the spatial spectrum estimation method, the PD signal is focused into narrowband signal by broadband focusing algorithm, and then the direction of arrival is obtained by narrowband direction finding algorithm. There are many kinds of broadband focusing and narrowband direction finding algorithms, and the direction finding performance of different algorithms is affected by signal-to-noise ratio, incident direction and so on. Therefore, it is necessary to study the selection of algorithms suitable for PD direction finding in substation station domain. In this paper, a PD simulation system is established. By changing the number of array elements, signal-to-noise ratio and incident azimuth angle, the performance of broadband focusing algorithms such as two-side correlation transformation(TCT), rotating signal subspace and signal subspace transform is compared; in addition, the direction find ing accuracy of narrowband direction finding algorithms is compared, such as multiple signal classification, root multiple signal classification(Root-MUSIC), and signal parameter estimation via rotational invariance techniques and weighted subspace fitting. The simulation results show that TCT algorithm has the fastest operation speed, the widest effective direction finding range and the highest direction finding accuracy when the signal-to-noise ratio is high. Root-MUSIC algorithm has the smallest direction finding error when the number of array elements is small, and has strong ability of noise suppression and short calculation time. In experiments, when TCT and root MUSIC algorithm are used in PD direction finding system, the deviation and standard devia tion of azimuth direction finding are less than 3.2° and 2.9° respectively, which have better direction finding performance.更多还原