基于特征子系统的广义短路比导出原理及计算方法  

Derivation Principle and Calculation Method of Generalized Short-circuit Ratio Based on Eigen-subsystems

作　　者：辛焕海[1] 刘晨曦 黄林彬[1] 高晖胜 鞠平 XIN Huanhai;LIU Chenxi;HUANG Linbin;GAO Huisheng;JU Ping(College of Electrical Engineering,Zhejiang University,Hangzhou 310027,Zhejiang Province,China)

机构地区：[1]浙江大学电气工程学院,浙江省杭州市310027

出　　处：《中国电机工程学报》2025年第7期2447-2460,I0001,共15页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家自然科学基金项目(联合基金项目)(U22B6008,U2166204)。

摘　　要：随着跟网型新能源/电力电子装备的大规模接入,系统电压支撑强度降低,新型电力系统的安全稳定风险增加。在同构新能源/电力电子装备接入场景下,利用电网广义短路比和装备/场站临界短路比可以形成与稳定性强相关的系统电压支撑强度量化方法;在弱异构场景下,基于装备和电网动态的特殊性质,利用广义短路比和装备/场站临界短路比的一阶近似可以实现强度量化,但针对不同场景的导出原理及计算方法难以统一。为此,该文聚焦小扰动维度下电压支撑强度量化问题,首先,利用多馈入系统可近似解耦为多个低维子系统的规律,提出特征子系统的概念和计算方法,并诠释其物理意义;其次,基于特征子系统,提出广义短路比及装备/场站临界短路比的导出原理及通用计算方法;此外,针对电力电子装备在非额定运行点、部分装备有功功率反向以及包含构网型装备的场景下,给出广义短路比的具体计算公式;最后,算例验证所提原理和方法的有效性。With the large-scale integration of renewable energy sources and grid-following power electronic devices,the voltage support strength of power systems decreases dramatically,posing threats to the secure and stable operation of the new type power system.In the scenario where homogeneous power electronic devices are integrated into the system,the so-called generalized short-circuit ratio(gSCR)of the power network and the critical short-circuit ratio(SCR0)of the device/stations can be used to quantitatively evaluate the voltage support strength of the system.Such a method is highly related to the system stability.In the scenario where heterogeneous power electronic devices(exhibiting weakly different dynamics)are integrated into the system,the voltage support strength can be quantified by the first-order approximation of gSCR and SCR0,utilizing the special characteristics of the devices and the power grid.However,there is still a lack of unified derivation principles and calculation methods to handle the heterogeneous cases.To this end,this paper focuses on quantifying the voltage support strength of the system with respect to small-signal stability.We found that the multi-infeed system can be approximately decoupled into multiple low-dimensional systems.On this basis,we propose the concepts of eigen-subsystem and its calculation method,and further interpret their physical meaning.Based on the concept of eigen-subsystems,the generalized derivation principle and calculation methods of gSCR and SCR0 are proposed.Additionally,the specific calculation methods for these metrics are provided when considering grid-following converters under non-rated operating conditions,reverse active power outputs,and grid-forming devices.Finally,the effectiveness of the principles and methods is verified in numerical case studies.

关 键 词：广义短路比 装备/场站临界短路比 特征子系统 

分 类 号：TM712[电气工程—电力系统及自动化]