【作者】 韩志勇；

【导师】 贺仁睦；

【作者基本信息】 华北电力大学（北京） ， 电力系统及其自动化， 2009， 博士

【摘要】 现代电力系统中发电机组容量不断增大,发电机组动态对电力系统稳定的影响日益增强。目前,大机组与大电网的相互影响与协调已成为直接影响电力系统安全运行的重要问题。本文按照理论分析、仿真验证、现场实测和实际应用相结合的思路,主要对电力系统机网动态安全稳定进行了研究,主要创新成果如下:1、建立了机网耦合模型和仿真平台。考虑蒸汽压力脉动的汽轮机模型、尾水管水压波动的水轮机模型及相应控制系统模型,详细的发电机、电网各元件数学模型,建立了发电机组和电网(简称“机网”)耦合数学模型;基于电力系统分析软件,建立了机网耦合仿真平台,为分析机网动态耦合及机网耦合对电网动态稳定的影响奠定基础。2、分析了单机系统和多机系统不同振荡模式下共振机理功率振荡的振荡特性。提出了机网耦合共振机理功率振荡的能量表达式,从能量角度探讨了机网耦合共振机理功率振荡过程中内、外能量的变化关系和特征,并进一步分析了机网耦合共振机理功率振荡与传统负阻尼机理低频振荡的区别和联系。3、提出可能引发电力系统共振机理功率振荡的扰动源。研究了发电机组汽轮机热力参数、水轮机水力参数、转子轴系机械参数对原动机输出功率的影响,分析可能引发电力系统共振机理功率振荡的扰动源,并对原动机侧扰动与电网负荷扰动所引发的功率振荡进行了对比分析,为分析实际电力系统中发生的功率振荡现象提供参考。4、研发了基于同步采样的机网动态参数综合测量装置。综合考虑汽轮机(或水轮机)、发电机和电网之间的动态耦合特性,将发电厂中的热工参数、水力参数和转子轴系机械参数以及电网电气参数量测相结合,实现机网动态参数的同步采样,为研究机网动态安全稳定性提供第一手资料。5、提出并应用了基于实测的机网动态安全评估方法。采用Prony方法分段分次分析机网动态参数综合测量装置采集的现场实测数据,并将汽轮机热力参数、机械参数与电网电气参数的动态特征进行对比研究,确定汽轮机、发电机和电网之间的动态耦合特性,结合电网小干扰稳定分析,实现基于实测数据的机网动态安全评估。在此基础上,开发了基于实测的机网动态安全评估系统,提高了运行人员对机网动态稳定性的监测水平。更多还原

【Abstract】 With the increasing capacity of generating units in modern power systems,the dynamic behaviors of generator sets have larger effects on power system stability than ever before.At present,the interaction and coordination between big generating sets and large-scale power grids have become important issues,which directly impact on power system security.According to theoretical analysis,simulation validation,field measurement and practical application,this thesis focuses on dynamic stability of machine-network in power systems.Some new ideas and main achievements are as follows:The thesis establishes machine-network coupling models and the related simulation platform.The steam turbine model considering steam pressure pulsation,water turbine model considering draft turbo water pressure pulsation and their control system model are established.Based on power system analysis software,machine-network coupling simulation platform is built up,which lays the foundation for studying machine-network coupling and its effect on power system dynamic stability.The thesis presents the resonance mechanism for power oscillation introduced by machine-network coupling.The characteristics of resonance mechanism power oscillation are analyzed in single machine system and multi-machine system under different modes.The resonance mechanism in power system is explained from the energy point of view.The characteristics of energy in power system and the relationship between inside and outside energy of power system are analyzed.The differences and relationship between resonance mechanism oscillation and negative damping mechanism low frequency oscillation,sub synchronous oscillation are studied.The thesis presents the sources of disturbance inducing power system low frequency oscillation of resonance mechanism.The effects of steam turbine thermal parameters,water turbine hydraulic parameters and rotor mechanical parameters on prime mover output power are studied.The disturbance sources,which may be introduce power system resonance mechanism power oscillation,are found.The difference of the tie line power oscillation,which introduced by the prime mover power disturbance and the load disturbance,are studied in theory.The conclusion can provide the reference to understand low frequency oscillation phenomenon occurred presently in power system. The machine-network dynamic parameters comprehensive measurement equipment based on the synchronous sampling is researched and applied in practice.Considering the dynamic coupling characteristics between steam turbine(and water turbine), generator and electric network,the steam turbine thermal parameters,water turbine hydraulic parameters,rotor mechanical parameters and electric parameters are measured, realizing machine-network dynamic parameter synchronized sampling.It provides the first-hand materials for researching machine-network dynamic security stability.The thesis presents and applies the machine-network dynamic security evaluation method based on field measurement.The field-measured data collected by the comprehensive measurement equipment are analyzed using Prony method according to the time-domain and frequency-domain characteristics.The dynamic coupling characteristics between turbine,generator and electric network are determined. Combined with power grid small disturbance stability analysis,the machine-network dynamic security evaluation based on the measured data is realized.Then the actual machine-network dynamic security evaluation system has developed based on field measurement to enhance the operator the monitor level of machine-network dynamic stability.更多还原