低频振荡时的汽轮机调速控制方式在线调整策略

现场运行证明,若汽轮发电机组发生低频振荡,则可尝试改变调速系统控制方式以抑制振荡。已有研究表明,若电网侧的低频电功率振荡扰动引起机械功率共振,会使转子角振幅大幅增加。因此,分析了汽轮发电机组调速系统在串级比例—积分（PI）和2种单级PI控制方式下的阻尼特性和频率特性,提出了控制方式的调整策略,以避开共振频率点。仿真表明,发生共振时,通过调整调速系统的控制方式,能有效地降低转子振幅。该方法依托调速系统的现有功能进行低频振荡抑制,便捷有效且能在线调整,对系统的稳定运行具有现实意义。

An On-line Adjusting Strategy for Turbine Speed Control Under Low Frequency Oscillation

It has been proved by field operation that if low-frequency oscillation occurs with turbines,oscillation can be checked by changing the control mode of the speed control system.Literature analysis shows that if the low-frequency power disturbance on the grid side causes mechanical power resonance,the rotor angle amplitude will substantially increase.Hence,by analyzing the damping and frequency characteristics of the turbine control system in serial PI and two kinds of single stage PI control mode,an adjustment strategy is proposed to avoid the resonance frequency.Simulation shows that the amplitude of the rotor can be effectively reduced by turbine control mode adjustment when resonance occurs.This method is of practical significance for ensuring stable operation of the system by quickly checking the low frequency oscillation with the function available of the turbine regulating system on-line.