构网型控制在提升高比例新能源并网系统振荡稳定性中的应用

Application of Grid-Forming Control in Improving the Oscillation Stability of Power Systems With High Proportion Renewable Energy Integration

为了研究能够支撑新能源系统稳定运行的构网型与跟网型机组间比例关系,首先以单风场并网系统为例,分析了跟网型和构网型机组的并网动态特性;然后从保持并网风场在低频和次同步频段内振荡稳定性的角度,提出了风场内配置构网型机组容量的计算原则;在此基础上基于三机九节点算例系统,探究了100%新能源构成系统稳定运行的可行性,研究了系统内构网型机组的比例和位置等因素对系统动态特性的影响。研究表明,在风场内配置少量构网型机组即可有效改善弱电网下风场的次同步振荡问题,场内构网型机组的配置容量主要受低频模态稳定性的约束;在100%新能源系统内,构网型控制对远端跟网型机组支撑不足导致的次同步振荡是决定构网型控制需求的关键约束。

In order to study the ralationship between grid-forming(GFM)and grid-following(GFL)units that can support the stable operation of renewable systems,this paper firstly takes the single wind farm integrated system as an example to analyze the dynamic characteristics of the GFL and GFM units.Then,from the perspective of maintaining the oscillation stability of wind farms both in low frequency and subsynchronous frequency bands,the calculation principle of the GFM unit capacity to be deployed in wind farms is proposed.On this basis,based on the three-machine-nine-bus system,the feasibility of the stable operation of the 100%renewable system is explored,and the influence of the proportion and location of the GFM units on the dynamics of the system are studied.The results show that the subsynchronous oscillation(SSO)risk can be effectively improved by deploying a small number of GFM units in the wind farm,and the capacity of GFM units is mainly constrained by the low-frequency mode stability.Besides,in the 100%renewable system,the SSO due to inadequate support of GFM to the remote GFL units is the key constraint in determining the need for GFM units.