基于子带分量分解与独立分量分析的系统谐波阻抗估计方法  

System harmonic impedance estimation method based on sub-band component decomposition and independent component analysis

作　　者：林顺富 颜昕昱 钟良亮 李东东 符杨 LIN Shunfu;YAN Xinyu;ZHONG Liangliang;LI Dongdong;FU Yang(College of Electrical Engineering,Shanghai University of Electric Power,Shanghai 200090,China;State Grid Ningbo Power Supply Company,Ningbo 315000,China)

机构地区：[1]上海电力大学电气工程学院,上海200090 [2]国网宁波供电公司,浙江宁波315000

出　　处：《电力自动化设备》2021年第1期179-185,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51977128);上海市科委研究项目(17020500800);上海市人才发展资金资助项目(2018004)。

摘　　要：新能源的大量接入使得配电网的谐波污染愈发严重,系统谐波阻抗的精确估计是准确判别谐波责任的关键。新能源并网逆变器发射的谐波与网侧谐波之间存在一定的相关性,导致现有方法的精度降低甚至失效。为此,提出一种基于子带分量分解与独立分量分析的系统谐波阻抗估计方法。首先,通过小波包分解将并网连接点(PCC)处谐波电压、电流的观测信号分成各子带信号,并计算得到各子带的互信息值;然后,选择互信息值最小的子带作为独立子带,并在该子带上通过独立分量分析求得分离矩阵,以实现相关谐波源信号的分离;最后,通过系数矩阵中各元素间的数学关系求得系统谐波阻抗值。仿真分析结果表明:在PCC两侧发射谐波间存在一定相关性的场景下,所提方法能够有效地减小网侧谐波带来的误差,相较于已有方法拥有更好的估计精度与鲁棒性。The extensive access of renewable energy sources makes the harmonic pollution of distribution network more serious,and the accurate estimation of system harmonic impedance is the key to accurately determine the harmonic responsibility.There is a certain correlation between the harmonic emitted by gridconnected inverter of renewable energy sources and the grid-side harmonics,which results in the accuracy decrease or even failure of the existing methods.Therefore,a system harmonic impedance estimation method based on sub-band component decomposition and independent component analysis is proposed.Firstly,the observed signals of harmonic voltage and current at PCC(Point of Common Coupling)are divided into several sub-band signals by wavelet packet decomposition,and the mutual information value of each subband is calculated.Then,the sub-band with the minimum mutual information value is selected as the independent sub-band,and the separation matrix is obtained through independent component analysis in this subband,so as to realize the separation of related harmonic source signals.Finally,the system harmonic impedance is calculated by the mathematical relationship among the elements in the coefficient matrix.Simulative results show that the proposed method can effectively reduce the error caused by grid-side harmonics in the scenario where there is a certain correlation between the emitted harmonics of both sides of PCC,and has better estimation accuracy and robustness compared with the existing methods.

关 键 词：电能质量 系统谐波阻抗 小波包分解 独立分量分析 谐波责任划分 谐波分析 

分 类 号：TM711[电气工程—电力系统及自动化]