电网的分散负荷安全域及其应用(二):线路静态失稳的边界-本质-形态及负荷安全域的稳定裕度
Distributed Load Security Domain and Its Application(I):Boundary-essence-form of Line Static Instability and Stability Margin of Load Security Domain
竺炜 1肖魏 1罗贤超 1于瀚翔 1郑超2
作者信息
- 1. 长沙理工大学电气与信息工程学院,湖南省 长沙市 410114
- 2. 中国电力科学研究院有限公司,北京市 海淀区 100192
- 折叠
摘要
交流线路承载的静态稳定边界问题一直悬而未决.负荷安全域可约束线路压差、维持多级电网电压安全水平,但稳定裕度未知.传统静态功角稳定与电压稳定的概念、机理及分析方法都不相同.研究发现,针对线路两种静态稳定可形成统一的概念、机理,而全网静态稳定的充要条件是每条支路都满足静态稳定.基于线路的复变量状态方程,得到末端的复功率-电压(即 Pj-Qj-Uj)、复功率-功角(即 Pj-Qj-θij)的独立方程;通过可解条件分析、偏导证明,得到唯一的Pj-Qj稳定边界及其特征,证明两种失稳的同质性;通过解析几何分析,推导 Uj和θij的稳定边界及其特征,得到符合实际情况的失稳形态解释.基于Pj-Qj稳定边界,提出线路负荷安全域的稳定裕度指标以及电压安全水平的修正方法.理论验证基于首端参考系线路模型分析的可行性,提出电网上下级拓扑的稳定域匹配方法.最后,基于状态可观性判据、方程独立性以及平衡点生成原理,分析线路功-角特性的局限性.算例表明,所提的稳定边界、稳定域匹配方法都与 PSASP程序收敛性结果吻合.在新能源大量接入导致线路潮流波动性大的背景下,该研究更具理论价值及现实意义.
Abstract
The static stability boundary problem of AC transmission line remains unresolved.The load safety domain can constrain the line voltage difference and maintain the safety level of the multi-level grid voltage,but the stability margin is unknown.Traditional static power-angle stability and voltage stability are different from the concept,mechanism and analysis method.It is found that a unified concept and mechanism can be formed for the two types of static stability of the line,and the sufficient condition for static stability of the whole grid is that each branch satisfies static stability.Based on the complex variable state equation of the line,the independent equations of complex power-voltage(Pj-Qj-Uj)and complex power-power angle(Pj-Qj-θij)at the end are obtained.Through solvable condition analysis and partial derivation proof,the unique Pj-Qj stability boundary and its characteristics are obtained,and the homogeneity of the two kinds of destabilize is proved.Based on analytical geometry,the stability boundaries and characteristics of Uj and θij are derived to get a destabilizing shape interpretation that conforms to the actual situation.Based on the Pj-Qj stability boundary,the stability margin index of the line load security domain and the correction method of the voltage safety level are proposed.The feasibility of the line model based on the head-end reference frame is theoretically verified,and the stability domain matching method of the upper and lower topology of the power grid is proposed.Finally,based on the state observability criterion,the independence of equations and the principle of equilibrium point generation,the limitation of line power-angle characteristic is analyzed.The examples show that the proposed stability boundary and stability domain matching methods are consistent with the convergence results of the PSASP program.Under the background that the large-scale access of new energy leads to the large fluctuation of line power flow,this research has more theoretical value and practical significance.
关键词
线路静态稳定/稳定边界/失稳形态/线路负荷安全域/稳定裕度Key words
line static stability/stability boundary/destabilized form/line load security domain/stability margin引用本文复制引用
基金项目
国家自然科学基金项目(52077009)
湖南省教育厅重点项目(20A013)
出版年
2024
国家科技期刊平台
NSTL
万方数据