Secure states Illustration of states ◆optimal dispatch ignoring losses maximum line loading of 400 MW 700MW 500MW 250MW 250MW unit #2 unit #1 ◆post contingency 1200MW consider that a transmission line has opened because of a failure 700MW 500MW Ma入( →500MW unit #2 unit #1 (overload) 1200MW 家电电力系统广域测量与控制四川省重点实验室 Secure states