Security Assessment in Power Systems Operation Using a Risk Analysis-based Optimization Technique

Probabilistic and Risk-based methods are raising more and more interest in the context of power systems operation because they represent a new approach to Security Assessment (SA) in deregulated electricity markets. Probabilistic approach allows to account for the high level of uncertainty that characterizes a power system under deregulation, whereas Risk-based techniques enable to quantitatively capture the factors determining the system’s security level by means of risk indices that quantify the degree of risk of a given operating condition. This paper proposes a novel approach to assess security in power systems operation using a risk index. The procedure involves two main steps: first, a probabilistic Optimal Power Flow (OPF) is performed, which uses a mathematical model of the power system’s security boundary as a constraint to account for security. Second, a risk index is derived based on the knowledge of both the system’s operating conditions obtained by the OPF solution and the security boundary. A statistical study can be performed on the risk index in order to acquire some useful information about it. The effectiveness of the proposed approach is tested and demonstrated using the IEEE two-area test system.