面向新能源外送系统次/超同步振荡的控制器参数协调优化

Coordination and Optimization of Controller Parameters for Subsynchronous/Super-Synchronous Oscillation in New Energy Delivery Systems

作为大规模可再生能源的主要输送方式,风电、光伏经高压直流输电(HVDC)并网外送的形式在新能源的异地消纳上发挥作用的同时,也引发了次/超同步振荡(SSO/SupSO)现象。对于风电引发的次/超同步振荡问题,尤其是对在直驱永磁同步机组(DD-PMSG)机/网侧控制器(GSC)参数与柔性直流输电(VSC-HVDC)送/受端控制器(SEC/REC)参数对于次/超同步振荡模式存在阻尼耦合的问题上的应对方案尚待深入研究。对此,该文通过优化风电柔直并网系统控制器参数来抑制系统次/超同步振荡,将阻尼耦合问题转换为控制器之间的参数协调优化问题。具体而言,以主导控制器参数作为优化变量,以待改善振荡模式为目标模式,以目标模式阻尼比最大化为优化目标,建立主导控制器参数的协调优化模型,采用了全局搜索性好、收敛速度快的I-PGSA算法对协调优化模型进行求解,获得最优控制器参数。在协调优化过程中,采用模式追踪技术对目标模式进行追踪锁定,确保优化的针对性;在约束条件中,提出了动态阻尼比概念并对各振荡模式的阻尼比阈值进行动态设定,保证优化的合理性。最后,基于PSCAD/EMTDC对控制器参数优化效果进行时域仿真和比对,结果验证了所提协调优化策略的有效性和优越性。

As the main transmission way of large-scale renewable energy resources, the form of wind power and solar power integrated grid by HVDC plays an important role in consuming new energy elsewhere. However, it also brings the potential risk of subsynchronous / super-synchronous oscillation (SSO/SupSO). The problem of SSO/SupSO caused by wind power, especially for the problem of damping coupling among machine-side controller (MSC)/grid-side controller (GSC) parameters of the direct-drive permanent magnet synchronous generator (DD-PMSG) and sending-end controller (SEC)/ receivingend controller (REC) parameters of VSC-HVDC, is still to be studied in depth. Based on the background mentioned above, this paper optimizes the controller parameters of the wind power integrated system by VSC-HVDC to suppress the SSO/SupSO, and transforms the damping coupling issue into the controller parameters coordination optimization issue. In detail, the dominant controller parameters are taken as the optimization variables in this paper. And the oscillation modes for improvement are selected as the objective modes. Maximizing the damping ratios of the objective modes is the optimization object. Then, the coordinated optimization model of the dominant controller parameters is established. The I-PGSA algorithm which has excellent performance in convergence speed and global searching ability is used to solve the coordinated optimization model, and the optimal controller parameters are obtained. The model tracking technique is used to track and lock the objective modes in the process of coordinated optimization, which makes the process of optimization more pertinent. The concept of dynamic damping ratio is further proposed, which is contained in constrains. It realizes the dynamic setting in the threshold of damping ratio of each oscillation mode in the process of optimization, which makes the process of optimization more rational. Finally, the time domain simulation based on PSCAD/EMTDC proves the effectiveness and superiority of the proposed coordinated optimization strategy.