电力系统共振机理低频振荡扰动源分析

共振机理是解释电力系统发生低频振荡的理论之一。文中根据汽轮机功率扰动引起电力系统低频振荡的共振机理，研究了汽轮机功率变化的原因。应用MATLAB建立了火力发电厂动力系统和电力系统相互作用的机网耦合模型。详细分析了锅炉燃烧率扰动和汽轮机调节汽门扰动能否引起汽轮机功率变化。仿真分析表明，调节汽门扰动频率与电力系统自然振荡频率一致或接近时，均可能引起电力系统发生共振机理的低频振荡。由于锅炉具有很大的惯性，锅炉燃烧率扰动很难引起电力系统发生共振机理的低频振荡。

The Cause Analysis of Turbine Power Disturbance Inducing Power System Low Frequency Oscillation of Resonance Mechanism

Resonance mechanism is one of the theories that interpret power system low frequency oscillation. According to the resonance mechanism, power disturbance of prime mover can arouse power system forced low frequency oscillations. Therefore, the causes of turbine power disturbance were analyzed in this paper. The coupling model between thermodynamic system of plant and power system was set up by MATLAB. The possibility of combustion ratio of boiler and control valve of governing system disturbance inducing the variation of turbine power was researched in detail. The simulation results indicate that power system low frequency oscillations of resonance mechanism might be caused by the disturbance of control valve, when it's frequency is consistent with or close to power system natural oscillations frequency. Because of the biggish inertia of boiler, the disturbance of combustion ratio cannot invoke power system low frequency oscillation of resonance mechanism.