考虑机组低频保护的电力系统暂态频率稳定评估  

Power System Transient Frequency Stability Assessment Considering Unit Underfrequency Relay Protection

作　　者：李常刚[1] 张恒旭[1] 刘玉田[1] 孙华东[2] 汤涌[2] 

机构地区：[1]山东大学电网智能化调度与控制教育部重点实验室,济南250061 [2]中国电力科学研究院,北京100192

出　　处：《电工技术学报》2013年第2期271-278,共8页Transactions of China Electrotechnical Society

基　　金：国家高技术研究发展计划(863计划)资助项目(2011AA05A118)

摘　　要：频率稳定反映电力系统在大扰动下维持频率在长时间运行可接受范围内的能力。分析暂态频率失稳的机理,认为机组因低频保护跳闸而导致有功平衡恶化是暂态频率失稳的必要条件,定义基于低频保护临界扰动功率的暂态频率稳定裕度指标,指标具有线性特征。为快速评估系统暂态频率稳定性,合理简化原动机-调速系统,推导计及旋转备用和低频减载的频率响应解析解。仿真结果表明,本方法能快速有效评估系统暂态频率稳定性,指导系统安全稳定运行。Frequency stability is the ability of a power system to maintain steady frequency during severe system upset. Mechanism of transient frequency instability is discussed. Unit tripping due to underfrequency relay may worsen active power imbalance and is treated as a necessary condition of transient frequency instability. A transient frequency stability index with fine linearity is defined with critical disturbance of unit underfrequency relay. Considering spinning reserve and underfrequency load shedding, an analytic model of frequency response is deduced for fast evaluation of transient frequency stability with reasonable simplification of turbine-governor system. Simulations show that system transient frequency stability can be evaluated with the proposed method quickly and effectively.

关 键 词：暂态频率稳定 机组低频保护 暂态频率偏移安全性 电力系统 

分 类 号：TM732[电气工程—电力系统及自动化]