With the continuous expansion of the scale of wind power and photovoltaic access to the grid

the peakto-valley load of the grid is gradually increasing

and the frequency control of the grid has a series of problems such as excessive overshoot and slow adjustment speed. Aiming at solving the problems occur during the load distribution and frequency control of the interconnected power system

this paper proposes a load frequency control method for the interconnected power system that considers the distribution coefficient of the generator set. Firstly

a two-region power grid automatic power generation control(AGC) system simulation model containing multiple thermal power units in a single region is established

and the economic objective function is established according to the coal consumption characteristics of each generating unit

and the optimal output distribution coefficient is obtained. Then

based on the control mode of tie-line power and frequency deviation control(TBC-TBC)

PID control optimized by Ziegler-Nichols related algorithms is adopted

and the robustness of the optimized PID controller is analyzed. Finally

based on a two-zone system

the simulation model is simulated and verified under certain load disturbance conditions. The simulation results show that

the allocation method can effectively save coal consumption

and the PID controller optimized by the proposed algorithm has certain advantages in frequency recovery speed

and has good robustness.