随着风电、光伏等新能源的大量接入，新型电力系统呈现出典型的“双高”特性，其发展也导致了日益突出的次同步振荡问题。由于次同步振荡具有广域传播特性，亟需研究复杂交直流电网中次同步振荡传播的影响因素和传播机制。文章提出了一种基于最大信息系数（maximum information coefficient, MIC）的次同步振荡传播影响因素的评价体系，并依据得出的强相关影响因素阐述了基于次同步功率传播分布系数的传播机制。结果表明：影响次同步振荡传播的强相关因素是交流线路潮流和次同步振荡频率下的交流线路阻抗特性，分别对应次同步功率中的交流分量和直流分量；次同步功率根据分布系数的比例在复杂交直流网络中传播。仿真结果验证了文章所提出的方法和机制的有效性。
英文摘要:
With the widespread adoption of new energy sources like wind and solar energy, the novel power system exhibits typical "double-high" characteristics, and as a result, sub-synchronous oscillations are becoming an increasingly significant issue. It is vital to research the influencing factors and propagation mechanism of sub-synchronous oscillations in complex AC-DC power grids since they have a wide area of propagation characteristics. This paper proposes an evaluation index system of sub-synchronous oscillation propagation influence factors based on the maximum information coefficient (MIC), and the propagation mechanism of sub-synchronous power propagation based on diversion coefficient is elaborated according to the derived strong correlation influence factors. The results indicate that the AC line power flow and the AC line impedance characteristics at the sub-synchronous oscillation frequency, which correspond to the AC component and the DC component of the sub-synchronous power, are the strongly correlated factors affecting the propagation of sub-synchronous oscillation. In the complex AC-DC grid, the sub-synchronous power propagates determined by the proportion of the diversion coefficient. The effectiveness of the approach and mechanism suggested in this paper is confirmed by the simulation results.