Analysis of Frequency Oscillation Caused by AGC Control in Yunnan Power Grid

Yunnan power grid is a large-scale HVDC sending system with high-proportion hydropower. Frequency oscillation events caused by the instability of the automatic generation control (AGC) occured repeatedly in Yunnan power grid. Combined with the reality of Yunnan power grid, a hydropower system model including AGC control is established to explain that the high-proportion hydropower and reduction in AC loads will lead to system frequency instability. Further study of the influence of governor deadband on frequency oscillation based on description function, and propose the setting method of frequency bias coefficient B to ensure frequency stability.