The damping of power system has become more and more weak with the regional power sytems interconnections. So the increasing risk of low frequency oscillation brings a serious problem of restricting the inter-regional power exchange and stability of power system. 尤其是区域电网的互联,导致系统的阻尼变得薄弱,低频振荡的风险加大,严重影响了区域间的功率交换和系统的稳定性。