Probabilistic Security Assessment in Power Transmission Systems: A Review

Abstract

Power system security is an essential part of power transmission system planning and operation. It is the ability of the power system to withstand sudden disturbances, such as electric short circuits or unanticipated loss of system components. Conventionally, security has been evaluated using deterministic criteria, such as (N-1) criterion, under worst-case severe system loading levels. However, such worst-case deterministic approach does not deliver a clear evaluation of the probability of component failure of the system, and the probability of the outages is treated equally. The key disadvantage of the (N-1) security criterion is that it only gives information about whether it is satisfied or not, making a comparison between possible candidates for power network expansion or a further investigation regarding system security quite complicated. With the advent of various renewable energy sources, particularly, wind and solar, and the rising complexity of power systems, the amount of uncertainty in power systems has considerably increased. These energy sources, in addition to the traditional uncertainty sources (load, generation availability, transmission assets, etc.) present the drawbacks of the traditional deterministic security assessment. Moreover, the occurrence of contingencies in power systems and their effects are non-deterministic, justifying the requirement to incorporate probabilistic approaches for power system security assessment. Considering its importance in power system planning and operation, this paper attempts to review some major works on probabilistic security assessment (PSA). Consequently, some significant research gaps are identified. It is believed this paper will be very beneficial for the power system research community, particularly, for students and researchers in the domain of power system security and risk assessment.