中文摘要：

受制于机械功率难以测量的实际情况,调速系统对低频振荡影响的在线分析较为困难。通过转矩分析分别研究了在不考虑和考虑调速2种情况下转速偏差、电磁功率偏差与机械功率偏差在功角-转速平面上的关系,发现：若调速系统提供了负阻尼转矩,则电磁功率偏差与转速偏差的夹角θ2将小于π/2与低频振荡阻尼比ξ之差;若调速系统提供了正阻尼转矩,则θ2将大于π/2-ξ。基于上述分析结果,提出一种基于监测量在线判断调速系统对低频振荡影响的方法。该方法通过在线辨识ξ和监测θ2来判断θ2与π/2-ξ的大小关系,即可确定调速系统是否对低频振荡提供负阻尼。4机2区域系统和某实际互联电力系统的仿真结果表明,在判断调速系统为低频振荡提供负阻尼后,通过使调速器进入开环控制模式能够有效提升振荡阻尼比,从而验证了所提方法的有效性和实用性。

英文摘要：

It is difficult to online analyze the influence of governor system on LFO（Low Frequency Oscillation） due to the fact that mechanical power cannot be measured directly. Based on the torque analysis,the relationship among the deviations of rotor speed,electromagnetic power and mechanical power on angle-speed plane is respectively discussed for the generator with and without governor system,which shows that,if the governor provides negative damping torque,the angle θ2 between rotor speed deviation and electrical power deviation will be less than（π/2-ξ）（π/2 minus LFO damping ratio ξ）,if the governor provides positive damping torque,then θ2 will be greater than（π/2- ξ）. Therefore,a way to online identify the influence of turbine governor system on LFO is proposed based on the monitored variables. The relationship between θ2 and（π/2- ξ） is determined according to the online detected ξ and monitored θ2,and then whether the governor system provides negative damping torque for LFO is identified. The simulative results for a 4-generator 2-area system and a real interconnected power system show that,after the negative damping torque provided by the governor for LFO is identified,the governor is then set in the open-loop control mode to increase the LFO damping ratio,verifying the effectiveness and practicability of the proposed way.