In the work, new protection principles are proposed to form a basis for anti-collapse complexes of power systems. The principles are founded on the detailed analysis of blackouts, the response of generating sources to the deviations in emergency parameters, the analysis of existing technical solutions, and on the long-term experience in liquidation of blackouts. As a result, a conception has been created for the anti-collapse preventive complex, according to which the emergency events are returned to their optimal course, the blackouts are eliminated within some tens of seconds without personnel participation, using feasible technical solutions that are verified in practice.