同型光热发电机并联聚合对光热发电场振荡稳定性影响

Impact of Dynamic Aggregation of Same Concentrating Solar Power Generators in Parallel Connection on the Oscillation Stability of a CSP Plant

该文研究了并联光热发电机群聚合对光热发电场振荡稳定性的影响,发现并联光热发电机数量增加时,与光热发电机励磁系统相关的振荡模式在复平面上向右移动,给光热发电场带来失稳风险。文中采用劳斯稳定判据,进一步分析证实并解释了这一发现的机理。该文首先给出了光热发电机组线性化模型,进而建立了含N台并联光热发电机的光热发电场线性化模型;然后,在光热发电机模型相同的条件下,采用相似变换推导了光热发电场等效模型,分析了并联光热发电机数量增加给光热发电场带来振荡失稳的风险,通过算例演示了随着并联光热发电机数量的增加,光热发电场的励磁振荡模式在复平面上向右移动,导致光热发电场振荡失稳,探讨了光热发电机运行状态不同时等效模型的适用性;最后通过理论分析表明,光热发电机机电振荡模式不受并联光热发电机数量增加的影响,从而证明和解释了励磁振荡模式失稳的机理。

In this paper,the impact of concentrating solar power(CSP)generators in parallel connection on oscillation stability of a CSP plant is studied.It is found that the increase of the number of CSP generators in parallel connection may cause the oscillation mode associated with the excitation system of CSP generator to move to the right on the complex plane,which brings the risk of instability.Based on the Routh stability criterion,further analysis confirms and explains the mechanism of this discovery.Firstly,the linearized model of CSP generator is presented,and then the linearized model of CSP plant with N CSP generators in parallel connection is established.Then,the equivalent model of CSP plant is derived with similar transformation under the condition that CSP generators are all the same.Then,the risk of oscillation instability caused by the increase of the number of parallel CSP generators is analyzed.An example shows that with the increase of the number of parallel CSP generators,the oscillation mode associated with the excitation system of the CSP plant moves to the right on the complex plane,resulting in the instability of the CSP plant.Then,the applicability of the equivalent model is discussed when the dynamic of the CSP generator is different.Finally,the theoretical analysis shows that the electromechanical oscillation mode of the CSP generator is not affected by the increase of the number of parallel CSP generators,thus proving and explaining the mechanism of the instability of oscillation mode associated with the excitation system.