On risk-based indices for transmission systems

This paper introduces new probabilistic indices for power system transmission problems. They are based on the number, degree and duration of violations caused by equipment outages and changing operating conditions. The indices include the absolute risk, relative risk and sharpness of violations. The absolute risk reflects the magnitude of transmission problems in terms of expected duration, number of affected facilities, and mean degree of violations. The relative risk identifies parts of the system where violations are most intense as compared to the system size. Along with the area risks, individual risks for contingencies or buses/branches can be computed. Sharpness quantifies the degree of locality of these problems. New indices are useful for transmission planning and operations. For example, the effect of improvements, generation dispatches, or inter-area power transfers can be evaluated.