As a clean and renewable energy source, solar energy has the advantages of inexhaustible, pure and pollution-free. Photovoltaic power generation is different from traditional thermal power generation in that it is more susceptible to external environmental factors. In addition, there are a large number of power electronic devices in the entire system. These various factors will bring a significant shock to the grid power quality after grid connection. The research of grid-connected power quality system is becoming more and more important. A series of researches are carried out around a complete three-phase photovoltaic grid-connected system, which are modeled separately, connected to the distribution network for simulation analysis, and analyzed the power quality impact on the distribution network. Based on the traditional disturbance observation method, this paper proposes a new MPPT algorithm that combines the constant-voltage tracking method with the three-point comparison method (an algorithm derived from the traditional disturbance observation method). This complete three-phase photovoltaic grid-connected system was connected to an IEEE 14-node distribution network, and the impact of grid-connected capacity and grid location on the power quality of different nodes in the distribution network was analyzed. An improved power management scheme is proposed. Finally, the paper analyzes the improvement of power quality by connecting a group of hybrid reactive power compensation device which is composed of static reactive power compensator and shunt capacitor. The results show that the voltage deviation is reduced and the harmonic content is reduced. It can be considered that this measure has achieved the purpose of power quality control to a certain extent.

太阳能作为一种清洁，可再生的能源，具有取之不尽，用之不竭，无污染的优点。光伏发电与传统火力发电的不同之处在于，它更容易受到外部环境因素的影响。另外，整个系统中有大量的电力电子设备。这些因素将在并网后给电网电能质量带来重大冲击。并网电能质量系统的研究越来越重要。围绕完整的三相光伏并网系统进行了一系列研究，这些系统分别建模，连接到配电网以进行仿真分析，并分析了电能质量对配电网的影响。在传统干扰观测方法的基础上，提出了一种新的MPPT算法，该算法将恒压跟踪方法与三点比较方法（传统干扰观测方法派生的算法）相结合。将该完整的三相光伏并网系统连接到IEEE 14节点配电网络，并分析了并网容量和电网位置对配电网络中不同节点的电能质量的影响。提出了一种改进的电源管理方案。最后，通过连接一组由静态无功补偿器和并联电容器组成的混合无功补偿装置，分析了电能质量的提高。结果表明，电压偏差减小，谐波含量减小。可以认为该措施在一定程度上已经达到了电能质量控制的目的。