Boundaries of Power System Frequency Regulation Ability

The upper and lower boundaries of power system frequency regulation ability are defined in this paper. System stability limits the upper boundary, and system safety limits the lower boundary. It is recommended that the best power system regulation ability should not exceed the upper boundary or the system will be unstable, and that the worst regulation ability should not exceed the lower boundary or the system will be out of control due to a large sudden load change. The upper boundary, i.e. stability boundary, is the emphasis of this paper. The effects of some possible factors including the linear and nonlinear factors and the system oscillation on stability boundary are explored.