系统结构对多馈入直流系统短路比的影响  

Influence of System Structure on Multi-infeed HVDC Short Circuit Ratio

作　　者：张啸虎 陈陈[2] ZHANG Xiaohu;CHEN Chen(State Grid Company East China Division,Pudong New District,Shanghai 200120,China;Department of Electrical Engineering,Shanghai Jiao Tong University,Minhang District,Shanghai 200240,China)

机构地区：[1]国家电网公司华东分部,上海市浦东新区200120 [2]上海交通大学电气工程系,上海市闵行区200240

出　　处：《中国电机工程学报》2018年第16期4777-4783,共7页Proceedings of the CSEE

摘　　要：基于线电压换相的常规直流输电需要交流系统提供理想的换相电压,因而落点交流系统的强度非常重要。多回大容量直流集中馈入使受端系统交直流比例发生根本变化,严峻挑战系统的安全稳定性。国内外针对此类问题已开展多方面研究,如：直流优化及协调控制、直流落点选择、交流系统最小开机、动态无功支撑等;但对交流系统网架结构调整以提高交直流系统稳定水平还未见报导。此外,近期拟在换流站安装调相机来提高受端动态无功支撑,但随之发生的交流短路电流超标,又需安装串联电抗加以限制,综合效果如何,尚待深入研究。该文基于判断多馈入系统强弱的有效指标,即多馈入短路比,应用系统阻抗矩阵支路追加法,分析交流电网系统结构变化,即网络参数变化对多馈入直流系统强弱的影响,从而为改变网架结构提升交直流系统安全稳定水平提供了理论支撑和计算方法,文中还给出了基于短路电流、多馈入短路比的网架结构变化策略建议。Since the commutation of convertor relies on ac system voltage the relative strength of AC system is critical for line-commutated converter transmission. As more and more HVDC systems infeed to the load center, the power supply mode greatly changed and the stability and safety of AC / DC systems is faced up to severe challenge. Papers have been published on this issue, including DC optimal and/or coordinate control, DC infeed allocation, minimizing AC generation units in operation, dynamic reactive support and so on. However, adjusting AC grid structure to improve the stability level of AC / DC system has not been revealed. Recently condensers at the receiving terminal are supposed to improve the dynamic reactive power support, along with which the short-circuit current is raised up, however, series impedance is added to offset it. The comprehensive effect of all of them is not clear yet multi-infeed short circuit ratio （MISCR） is an effective indicator of transmission system strength. The branch additional method was applied on the system impedance matrix to analyze the influence of system structure on MISCR. It gives the guidance how to strengthen the multi-infeed AC/DC system by adjusting the power grid structure.

关 键 词：多馈入直流系统 多馈入短路比 网架结构 阻抗矩阵 支路追加法 

分 类 号：TM71[电气工程—电力系统及自动化]