分布式光伏并网系统电压越限风险及谐波影响

在“源-网-荷-储一体化”协同发展背景下，随着电力电子技术的发展，光伏并网引发的电压波动、谐波畸变等问题进一步显现，因此明确分布式光伏并网系统内电能质量问题产生的机理，对保持配电系统的经济稳定运行至关重要。研究了光伏并网系统多种典型电能质量问题的发生机理，介绍了典型的光伏并网系统的结构特点和运行原理；根据原理分析了光伏并网对电压偏差和功率因数的影响；通过分析原理及仿真数据对比介绍了分布式光伏引起的谐振风险以及谐波畸变情况。根据低压光伏台区实测数据以及仿真算例，分析了分布式光伏并网对电压偏差、电压波动、谐波电压等电能质量指标的影响，结果表明，光伏并网会引起电压波动、谐振、谐波等电能质量问题，因此在推进光伏并网的同时，既要考虑电能质量制约因素，又要考虑大规模光伏并网带来的消纳问题。

Voltage Instability and Harmonic Risk for the Distributed Photovoltaic Grid-Connected System

Under the background of the coordinated development of “source-grid-load-storage integration”， with the development of power electronics technology， issues such as voltage fluctuations and harmonic distortion caused by photovoltaic grid-connection have further emerged， so it is important to clarify the mechanism of power quality issues in distributed photovoltaic grid-connected systems to maintain the economic and stable operation of distribution systems. This paper explores the mechanism of various typical power quality problems in photovoltaic grid-connected systems and introduces the structural characteristics and operating principles of typical photovoltaic grid-connected systems； the influence of photovoltaic grid connection on voltage deviation and power factor is analyzed according to the principle. In addition， the resonant risk and harmonic distortion caused by distributed photovoltaic are introduced by analyzing the principle and comparing the simulation data. Finally， based on the measured data of the low-voltage photovoltaic station area and simulation examples， the influence of distributed photovoltaic grid connection on power quality indicators such as voltage deviation， voltage fluctuation， and harmonic voltage is analyzed. The results show that grid-connected PV can cause power quality problems such as voltage fluctuations， resonance， harmonics， etc. Therefore， while promoting grid-connected PV， attention should be paid not only to power quality constraints ， but also to absorption and consumption issues brought about by large-scale grid-connected PV.