This paper investigates the requirements of power system frequency stability for the frequency regulation capability of inverter-based power sources

represented by wind and solar power

and innovatively proposes the consideration index of the active power-energy time-domain curve for frequency support after disturbances. Firstly

considering the difference in frequency spatial distribution after disturbances

a power grid frequency dynamic model with multi-area inertia centers is constructed. The impact of dead-bands and amplitude limits in frequency regulation by heterogeneous power sources is taken into account

and an algebraic approximation model is obtained using the forward difference method. Secondly

a calculation model for active power-energy demand boundaries considering frequency stability is proposed

which is applicable to scenarios such as multi-area systems

multiple types of disturbances

and multi-period boundary calculations. The boundary calculation under frequency stability constraints is equivalently transformed into a two-stage robust optimization problem. Subsequently

a solution algorithm based on column and constraint generation (C&CG) is designed

and a variable difference step-size modeling strategy is proposed to reduce the cost of model solving. Finally

the effectiveness of the proposed method is verified through a simulation case study using the IEEE 39-bus system.