To solve the problem of inadequate reserve of provincial control areas during special periods such as peak load regulation or accident disposal

the structure and strategy of flexible combination control for provincial areas is proposed. Regional power grid dispatch center flexibly selects provincial control areas to participate in joint control according to the principles such as reserve sharing in adjacent areas. Firstly

based on the existing boundary model of provincial control areas and area control error(ACE)calculation mode

automatic generation control(AGC)in regional power grid calculates the ACE of each sub-control area and then quickly obtain the ACE of the combined control area by superposition. Secondly

based on the uploaded information such as real-time reserve of provincial grid and considering factors of minimum reserve

frequency deviation coefficient and actual adjustable reserve

ACE of the combined control areas is distributed optimizedly to provincial grids for execution after grid security check of provincial(inter-provincial)sections. The goal of breaking the provincial barriers for reserve sharing and emergency support in case of accidents is achieved while reducing the unnecessary reverse regulation of control areas. The effectiveness of the control strategy is verified through the actual operation.