中文摘要：

针对串补输电系统的次同步谐振风险，提出了一种综合频率扫描和复转矩系数的定量评估方法。它首先利用阻抗一频率扫描获得串补输电网的简化等值模型及其参数；然后根据复转矩系数法推导出机组各扭振模式的阻尼显式表达式，兼顾了轴系机械阻尼和电气阻尼。实例研究表明：该方法与特征根分析法的结果一致，但它的原理简洁直观、计算量小，且为机网参数的显式函数，能对多模式SSR提供直接、精确和定量的阻尼结果，可应用于工程上多串补、多个电压等级复杂电网的SSR风险评估。

英文摘要：

In allusion to subsynchronous resonance （SSR） risk of power transmission system with series compensator, a quantitative evaluation method in which the frequency scanning and complex torque coefficient are integrated is proposed. Firstly, in the proposed method the impedance-frequency scanning is utilized to obtain the simplified equivalent model of power transmission system with series compensator and its parameters; then based on complex torque coefficient the explicit expressions of damping under various torsional vibration modes, in which the mechanical damping and electrical damping of shafting are taken into account, are derived. Case study results show that the results from the proposed method conform to those by eigenroot analysis, however the proposed method is succinct and intuitional and its calculation burden is less, besides, the expressions of the proposed method are the explicit function of parameters of generators and power network, so the proposed method can offer direct, accurate and quantitative damping results for multi-mode SSR. The proposed method can be applied to power grid with multi-series compensators and multi-voltage grades to perform SSR risk evaluation.