Power supply shortage during peak load period is exist in Hunan power gird

while the power transmission capacity from southwest Hunan is restricted. The present situation of regulation about power transmission from southwest Hunan is analyzed. The influence of Qishao UHVDC on Hunan power grid operation is also presented. Based on these analysis

some differential regulation adjustments of power transmission from southwest Hunan are proposed under heavy load operation modes. The constrain faults of power transmission from southwest Hunan are checked under typical operation modes at different load levels. Meanwhile the relevant transmission lines are checked by N-1 principle. The results show that differential enhancing power transmission capacity from southwest Hunan is feasible under heavy load operation modes.