偏远地区风电场并网控制系统间的交互影响分析

Analysis on interactive influence among grid-connected control systems of wind farms in remote areas

以我国西部某偏远地区风电场为实例,采用基于频率的RGA方法对偏远地区风电场并网系统间的交互影响做定量分析。通过Mason定理建立风电场并网等效输出阻抗模型以及长线路分布参数模型,确定多逆变器并网相对增益矩阵。在Simulink仿真平台中依据风电场实际参数建模仿真,分析可知不同系统频率对多逆变器并网时控制系统间交互作用影响表现为:在f<156 Hz频率段,多并网逆变器控制通道之间基本没有交互作用;随着频率增大,控制通道间出现负交互影响且逐渐增大,f=691 Hz时达到最大,此后出现方向相反的控制影响;当814 Hz<f<907 Hz时,控制通道间出现正交互作用;随着频率继续增大,相对增益值不断增大,f=1 004 Hz时正交互作用达到极值。基于此,深入分析风电场并网时随着逆变器并网台数和线路长度的改变控制交互影响动态变化的基本规律。

By taking a wind farm in a remote area of the western part of China as an actual case, a quantitative analysis on the in- teractive influence among the grid-connected systems of the wind farms in the remote areas is made herein with the frequency- based RGA method. In accordance with Mason＇s theorem, the equivalent output impedance model and the long-distance transmis- sion line distributed parameters model of the wind farm are established, and then the relative gain array （RGA） of the grid-con- nection with multiple inverters is determined. Through the modelling simulation made on the Simulink simulation platform, it is known from the analysis concerned that the representations of the interactive influences from different system frequencies on the control system during the grid-connection with multiple inverters are as follows： at the frequency segment f 〈 156 Hz, no any in- teractive effect is there among the control channels of the muhiple grid-connected inverters. Along with the increase of the fre- quency, the negative interactive effect occurring among the control channels gradually increases and reaches to the maximum when f = 691 Hz, and hereafter, the influence of the control with opposite direction occurs. During 814 Hz 〈f 〈 907 Hz, positive interactive effect occurs among the control channels. Following the increase of the frequency, the relative gain value continuously increases and the positive interactive effect reaches to the extremum when f-- 1 004 Hz. On the basis of this, the basic law of the dynamic change of the control of the interactive influence along with the change of the number of the grid-connected inverters and the length of the transmission line during the grid-connection of wind farm is deeply analyzed as well.