基于实测数据的集群式光伏并网系统谐振检测

The resonance detection method of clustered photovoltaic grid-connected systems based on measured data

在具有大量并网逆变器的集群式光伏并网系统中,多逆变器之间、逆变器与电网之间的交互影响可能导致谐振,威胁光伏并网发电系统的正常稳定运行。准确的谐振检测方法是实现进一步有效抑制的基础。针对该问题,基于光伏并网系统实测数据,提出了一种小波变换(wavelet transform,WT)和快速傅里叶变换(fast Fourier transform,FFT)相结合的谐振检测技术。该方法首先利用WT将信号的高频和低频部分分别进行处理,剔除部分干扰信号,然后利用FFT进一步确定谐波成分,可准确地检测谐振信号发生的时刻和幅值。通过MATLAB/Simulink仿真分析验证了所提谐振检测方法的有效性和准确性。

In a clustered grid-connected photovoltaic system with a large number of grid-connected inverters,the interaction among multiple inverters and that between inverters and the grid may lead to resonance,which threatens the normal and stable operation of the grid-connected PV system.An accurate resonance detection method is the basis for further effective suppression.In order to solve this problem,a resonance detection technique combining Wavelet transform(WT)and Fast Fourier transform(FFT)is proposed based on the measured data of grid-connected PV systems.The method first uses the wavelet transform to process the high and low frequency parts of the signal separately to eliminate some of the interference signals,and then uses the FFT to further determine the harmonic components,and thereby can accurately determine the moment and amplitude of resonant signal occurrence.The simulation analysis based on MATLAB/Simulink verifies the effectiveness and accuracy of the proposed resonance detection method.