Identification of vulnerable transmission lines for optimal TCSC placement to countermeasure the cascading outages

Recent power system blackouts typically originate from a sequence of cascading outages (CO) of the system components, especially power transmission lines. The large-scale blackouts exhibit a power law behavior in their probability distribution function, which is the fingerprint of the self-organized criticality (SOC) nature of power system blackouts. This means that the occurrence of large-scale blackouts is more likely than what may be thought. Accordingly, investigation and mitigation of the cascading outages risk (COR) should be taken into account in both the planning and operating stages of electric power systems. In this paper, a new mitigation strategy is proposed where the most vulnerable transmission lines are identified based on a modified AC version of ORNL–Pserc–Alaska (OPA) model and optimally compensated by thyristor-controlled series compensator (TCSC) installation to countermeasure the CO with the optimal installation cost. To validate the efficacy of the proposed method on large power systems, it is applied to the IEEE 118-bus test system. The comparative results show the ability of this method to decrease the consequences of CO in addition to its financially reasonable feasibility.