摘要
在建立大型光伏电站诺顿等效模型基础上通过阻抗分析法分析了大型光伏电站与电网之间以及光伏电站内逆变器之间的耦合作用,揭示了大型光伏电站谐波产生机理,即电网阻抗与逆变器等效输出导纳相互作用对某一频率处的谐波产生了放大作用。提出在逆变器输出端增加一条虚拟的导纳通路来消除系统对谐波的放大作用。将并网点电压通过由一阶惯性环节和二阶陷波器复合而成的系统反馈至控制器输出端,实现对逆变器等效输出导纳的改善。经该方法改善后的系统输出导纳对谐波具有滤除作用,且对基波无衰减。仿真及实验验证了理论分析的正确性。
Based on the equivalent Norton model of large-scale photovoltaic（LSPV） plants, the coupling among inverters in LSPV plant and between LSPV plant and the grid are studied through impedance analysis. The study reveals the harmonic mechanism that coupling between grid impedance and equivalent admittance of inverter will amplify harmonics in the system. To remove the amplification to harmonics, the strategy of adding a virtual admittance to filter harmonics is proposed. The strategy is realized to improve inverter admittance by the voltage at the point of common coupling（PCC） feedback through the combination of a first-order process and a second-order notch filter. The system with the proposed strategy owns characteristics of making harmonic current through the virtual admittance and fundamental frequency current blocked. In the end, the result of simulation and experiment validates theoretical analysis.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2016年第18期120-126,共7页
Power System Protection and Control
基金
青海省光伏发电并网技术重点实验室(2014-Z-Y34A)
关键词
大型光伏电站
电网阻抗
虚拟导纳
谐波治理
LSPV plants
grid impedance
virtual admittance
harmonic suppression
