直流配网是配电系统的主要发展方向,受非线性设备、不平衡负载等因素影响,系统中极易产生二次谐波,严重威胁系统运行稳定性与用电设备安全性.在系统规模较大的直流配网中,多有源滤波器协同滤波是治理二次谐波的方法之一,但由于滤波器之间存在耦合干扰,滤波性能与效果差别较大.建立多滤波器诺顿等效并网模型,基于相对增益矩阵理论提出了多滤波器交互影响机理分析方法,构建了滤波器输出电流变化量与谐波源电流变化量矩阵关系,分析了直流配网线路参数和滤波器控制参数对滤波效果的影响.利用PSCAD/EMTDC软件建立含多直流滤波器的直流配电网模型,在不同场景下验证滤波器交互影响分析的合理性;并利用RT-LAB软件搭建半实物仿真模型,进一步验证了方法的有效性.

DC distribution network is the main development direction of the power distribution system. Due to the influence of electronic equipment and other factors, the system is very easy to produce second harmonics, which seriously affects the stability of the system and the safety of electrical equipment. Multi-filter collaborative filtering in DC distribution network has become one of the methods to control the second harmonic. However, due to the coupling interference between the filters, the filtering effect is affected by multiple factors. This paper establishes a Norton equivalent grid-connected model of multiple filters and proposes a method for analyzing the interaction mechanism of multiple filters based on the relative gain matrix theory. This method establishes the matrix relationship between the change in the output current of the filter and the change in the harmonic source current and analyzes the influence of the grid parameters and controller parameters in the multi-filter grid-connected system on the filtering effect of the filter, and proposes a reasonable parameter selection method. Finally, this paper establishes a DC distribution network model with multiple DC filters in PSCAD/EMTDC, and simulates the parameters affecting the filtering effect and verifies the rationality of the analysis in the scenario of multiple harmonic sources. In addition, it builds a semi-physical simulation model in RT-LAB to further verify the effectiveness of the method.