摘要
直流配电网能够以较高的效率集成光伏发电系统。然而,随着直流配电网中光伏渗透率的不断提高,系统较容易产生功率振荡现象,近来已经成为一个热点问题。对于光伏发电系统而言,系统中存在着一些关键的非线性环节,因此现有的纯线性系统分析方法并不能很好的去解释功率振荡机制。基于此,该文提出使用描述函数法分析系统中非线性环节的影响。首先,建立包含所有环节的完整光伏发电系统频域模型。然后,基于此模型,采用描述函数法分析了系统的稳定性,相应的振荡频率和幅值可以准确的计算出来。同时,对相关的影响因素进行定量分析,发现与交流网不同,直流配电网的网络阻抗有利于抑制系统功率振荡。最后,通过硬件在环实验验证相关的理论的正确性。
DC distribution network can integrate PV generators with high efficiency.However,the power oscillation occurs easily with the increase of the penetration of PV generators,which has become a hot topic recently.There are some key nonlinear links in PV generators,hence the existing purely linear analysis methods cannot well explained the oscillation mechanism.To fill in this gap,this paper proposed a stability analysis method based on describing function (DF)to explore the influence of the nonlinear links.First,the complete model of the PV generator was established in the frequency domain.Then,based on the model,the DF method was adopted to analysis the system stability,through which both the oscillation frequency and amplitude can be calculated accurately.At the same time,the related influence factors were studied quantitatively.It is found that the grid impedance of the DC distribution network is beneficial to suppress the power oscillation,which is different from the AC grid.All the theoretical analyses were verified by the real-time hardware-in-loop (HIL)tests.
作者
夏杨红
孙勇
韦巍
XIA Yanghong;SUN Yong;WEI Wei(College of Electrical Engineering,Zhejiang University,Hangzhou 310027,Zhejiang Province,China;State Grid Jilin Electric Power Supply Company,Changchun 130021,Jilin Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第23期6814-6824,共11页
Proceedings of the CSEE
基金
国家重点研发计划(2017YFB0902002)
2017国网吉林省电力公司科技项目(SGTYHT/16-JS-198)~~
关键词
直流配电网
光伏发电系统
功率振荡
稳定性分析
描述函数
DC distribution network
PV generators
power oscillation
stability analysis
describing function
