摘要
随着直流和新能源等电力电子设备的大量接入,电力电子多馈入系统(简称多馈入系统)成为现代电力系统的一种典型形态。多馈入系统的安全稳定运行能力与其受扰后的电压响应性能密切相关,工业界常用系统电压支撑强度(简称系统强度)的概念描述由电网和设备动态构成的闭环系统的电压响应性能,用电网强度概念描述不考虑这些设备动态的等效交流电网的特性。现有研究一般认为电网强度与系统强度之间存在正相关性,并认为短路比能够描述电网强度,却并未揭示电网强度、短路比和系统强度之间的内在联系。为此,该文聚焦小扰动下的系统强度问题,从抗扰性、同步稳定性以及静态电压稳定性3个角度描述系统强度特性,回顾将多馈入系统动态解耦为多个单馈入系统动态的系统强度量化原理,阐明广义短路比指标与系统强度之间的解析关系,并揭示系统强度–电网强度–设备临界短路比三者之间的内在联系。研究表明,广义短路比反映了电网的多端口电压与电流的最大灵敏度,与短路电流无必然联系;电网广义短路比与设备临界短路比的相对值可一定程度反映多馈入系统的安全稳定裕度。进一步,给出用于量化系统强度的广义短路比集中判据和单母线视角下的分散判据,并阐明传统CIGRE多馈入短路比与广义短路比的联系和区别。最后,利用算例验证量化原理与方法的有效性。
With the large-scale integration of DC and renewable energy or other power electronic devices,power electronic multi-infeed systems(referred to as multi-infeed systems)have become a typical form of modern power systems.The safe and stable operation ability of multi-infeed systems is closely related to voltage response performances under the disturbance.The industry commonly uses the concept of system voltage support strength(referred to as system strength)to describe the voltage response performances of the closed-loop systems composed of power grid and power electronic devices,while grid strength describes the equivalent AC grid performance without considering the dynamics of these devices.The existing studies generally assume that there is a positive correlation between grid strength and system strength,and also assume that short-circuit ratio can describe grid strength.However,it does not reveal the internal relations among grid strength,short-circuit ratio,and system strength.To this end,this paper focuses on system strength issues under the small disturbance,and describes the system strength characteristics from the following three dimensions including disturbance rejection performance,synchronization stability,and static voltage stability.Then,this paper reviews the system strength quantification principle of decoupling multi-infeed systems dynamics into multiple single-infeed systems dynamics,and clarifies the analytical relations between generalized short-circuit ratio(gSCR)and system strength.On this basis,the internal relations among system strength,grid strength,device critical short circuit ratio are further revealed.The results show that the gSCR reflects the maximum sensitivity of the network’s multi-port voltage towards current,therefore it is not necessarily related to the short-circuit current.Moreover,the relative difference value between the gSCR and device critical short-circuit ratio can reflect the safety and stability margin of multi-infeed systems to some extent.Furthermore,the gSCR concentrated criterion and the dispersive criterions from the perspective of the single bus are proposed to quantify the system strength.This paper demonstrates the connections and distinctions between the traditional CIGRE multi-infeed short-circuit ratio and the gSCR.Finally,the effectiveness of the quantification principles and methods are verified by several cases.
作者
周瑀涵
辛焕海
鞠平
ZHOU Yuhan;XIN Huanhai;JU Ping(College of Electrical Engineering,Zhejiang University,Hangzhou 310027,Zhejiang Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2023年第10期3794-3810,共17页
Proceedings of the CSEE
基金
国家自然科学基金项目(U2166204,U22B6008)。
关键词
响应性能
电网强度
系统强度
广义短路比
设备临界短路比
response performance
grid strength
system strength
generalized short-circuit ratio
device critical short circuit ratio
作者简介
周瑀涵(1996),男,博士研究生,主要研究方向为新能源电力系统稳定分析与控制,zhouyuhan@zju.edu.cn;通信作者:辛焕海(1981),男,教授,博士生导师,主要研究方向为新能源电力系统稳定分析与控制,xinhh@zju.edu.cn;鞠平(1962),男,教授,博士生导师,主要研究方向为电力系统负荷建模与稳定分析,pju@hhu.edu.cn。
