一起水电机组引发系统功率振荡的原因分析

Cause Analysis on the System Power Oscillations Triggered by a Hydroelectric Unit

西藏电网A电厂有功功率调整时,电厂#1和#2机组的有功和无功同时出现波动,期间引起西藏电网内其他机组发生小幅度波动。针对机组引发系统功率振荡的原因进行理论分析,并对电气量变化进行初步的判断分析。使用PSASP仿真软件,根据电网当时实际运行情况进行不同母线电压下的电力系统稳定器(PSS)投退、稳定限额对电网的影响分析。根据事故影响分析结果,提出可行的防范措施,降低电网低频振荡的风险,同时强调PSS在低频振荡中的关键作用。

When performing the active power adjustment of the power plant A in the Tibet power grid,the active and reactive power of units#1 and#2 in the power plantfluctuated at the same time,during which a small amount offluctuations of other units are caused in the Tibet power grid.The theoretical analysis of the causes of system power oscillations triggered by the units are carried out while the preliminary judgment and analysis of the electrical quantity changes are conducted.By application of the PSASP simu-lation software,impact analysis by the casting out and sta-bilizing limits of the power system stabilizers(PSS)under different bus voltages of the grid is performed according to the actual operation of the grid at that time.According to the results of the accident impact analysis,feasible precau-tionary measures are proposed to reduce the risk of low-fre-quency oscillations in the grid,meanwhile,the key function of the PSS in low-frequency oscillations is emphasized.