由汽轮机压力脉动引发电力系统共振机理的低频振荡研究

强制型共振机理是引起电力系统低频振荡的原因之一,该文针对此原因,根据其共振机理,探讨了汽轮机功率变化的可能性,并综合考虑了汽轮机热力系统和电力系统的相互影响,从热力系统中寻找出电力系统发生共振机理的低频振荡扰动源。在仿真中采用详细的汽轮机压力功率模型,着重研究了汽轮机蒸汽压力脉动与电力系统发生共振振荡的关系。仿真分析表明,汽轮机主蒸汽压力和再热蒸汽压力脉动,当其脉动频率与电力系统自然振荡频率一致或相近时,均有可能引起电力系统发生共振机理的低频振荡。该研究结果对探讨电力系统低频振荡的原因具有一定的参考价值。

POWER SYSTEM LOW FREQUENCY OSCILLATION OF RESONANCE MECHANISM INDUCED BY TURBO-PRESSURE PULSATION

The forced resonance mechanism is one of many reasons of power system low frequency oscillations. According to the resonance mechanism, power disturbances of prime mover invoke power system forced oscillations. The possible causes of power disturbances of prime mover are analyzed in this paper. The interactions between turbine's thermal system and power system are considered and the sources of resonance mechanism low frequency oscillations in power system are searched from turbine's thermal system. The detailed pressure-power model of turbine is adopted in simulation, and then the relationships between turbo-pressure pulsation and power system forced oscillations are studied in particular. The simulation results indicate that power system low frequency oscillations of resonance mechanism might be caused by the pulsation of turbine's main steam pressure or reheat steam pressure, when their pulsating frequency is consistent with or close to power system natural oscillations frequency. The conclusion can provide reference to research into the causes of power system low frequency oscillations.