【摘要】 注入谐波信号的大小对阻抗测量精度和系统稳定运行具有重要意义，同时背景谐波与系统噪声对注入谐波信号幅值的限定干扰极大，尤其新型配电系统包含多变换器，其背景谐波与系统噪声常导致测量数据异常与数据缺失，严重影响谐波阻抗的测量精度。由此提出一种考虑背景谐波与系统噪声的注入式谐波阻抗测量方法。首先，基于配电网交流侧系统阻抗模型，提出针对背景谐波与系统噪声的注入电压阈值选定方法，以解决测量精度与稳定运行之间的矛盾。然后，提出移动绝对中位差法剔除异常值、分段三次Hermite插值法扩容数据，采用最小二乘法曲线拟合计算谐波阻抗，降低谐波阻抗的测量误差。最后，通过MATLAB/Simulink仿真分析与验证，证明了所提方法可以有效弱化背景谐波与系统噪声的影响，提高了谐波阻抗测量精度。更多还原

【Abstract】 The injected harmonic signal size is of great significance to the impedance measurement accuracy and stable operation of the system, meanwhile, the background harmonic and system noise greatly interfere with the limitation of the injected harmonic signal amplitude, particularly the complex situation of background harmonic and system noise and the new distribution network which contains multi-converters often make the measurement data anomalous and missing, which seriously affects the measurement accuracy of the harmonic impedance. Therefore, this paper proposes an injective harmonic impedance measurement method considering background harmonic and system noise. Firstly, based on the system impedance model on the AC side of the new distribution network, a new injection voltage threshold selection method is proposed for the complexity of background harmonic and system noise in the distribution network, in order to solve the contradiction between measurement accuracy and stable operation. Then the moving absolute median difference method is proposed to eliminate outliers, the segmented three times Hermite interpolation method is proposed to expand the data, and the least squares curve fitting is used to calculate the harmonic impedance to reduce the error of measuring harmonic impedance. Through MATLAB/Simulink simulation analysis and verification, it is proved that the proposed method can effectively weaken the harmonic of background harmonic and system noise, improve the harmonic impedance measurement accuracy.更多还原