超低频振荡的机炉功率源动态特性分析  

Dynamic Characteristic Analysis of Turbine-Boiler Behaving as Power Source of Extra Low-Frequency Oscillation

作　　者：竺炜[1] 谢振武[1] 钟鹏[1] 黄明涛 谭平 

机构地区：[1]长沙理工大学电气与信息工程学院,湖南省长沙市410114 [2]浙江省电力公司培训中心浙西分中心,浙江省建德市311600

出　　处：《电网技术》2015年第8期2270-2276,共7页Power System Technology

基　　金："湖南省高校创新平台开放基金项目(13K056)"的资助

摘　　要：已有研究表明,机组机械功率的振荡频率若接近电力系统固有振荡频率,可引起强迫式低频振荡。考虑锅炉、汽轮机模型以及4种机炉协调控制方式,分析了机炉系统在机端电功率扰动下输出机械功率的阻尼及动态特性。研究发现,由于机炉协调控制的功率反馈通道在电网侧扰动后变成了前馈通道,导致机炉系统的机械功率阻尼降低,振幅变大;在超低频频带内,典型模型的4种机炉协调控制都存在共振频率,且振幅比都大于2。研究证实了火电厂热力系统可作为电力系统超低频振荡的功率来源,对超低频振荡的原因分析和抑制方法研究具有实际意义。Studies had shown that forced low-frequency oscillation can be induced when oscillation frequency of mechanical power is close to natural oscillation frequency of power system. In this paper, the boiler and turbine models and four turbine-boiler coordinated control modes are considered; damping and dynamic characteristics of mechanical power output in turbine-boiler system under grid side power disturbance are analyzed. The study finds out that the power feed-back path of turbine-boiler coordinated control becomes a feed-forward path under grid side disturbance, making mechanical power damping decreased and oscillation amplitude increased in turbine-boiler system; in extra low-frequency band, resonance frequencies exist in four typical coordinated control modes, and amplitude ratios are greater than 2. The study has shown that thermodynamic system of thermal power plant can become power source of extra low-frequency oscillation in power system, which is of practical significance for extra low-frequency oscillation analyzing and inhibiting in power systems.

关 键 词：超低频振荡 电功率前馈 阻尼 幅频特性 机炉协调控制 

分 类 号：TM71[电气工程—电力系统及自动化]