An evolution strategy based approach for a congestion management system

In liberalized electricity systems, congestion management is one important task of the transmission system operator. To avoid multiple congested conditions, all the possibilities of the transmission system should be used. That can be: adjustment of the network elements; and corrective switching or corrective redispatch of the power generation. To support the transmission system operator, a congestion management system (CMS) is necessary, which searches an undisturbed system state. This search represents a mixed-integer-nonlinear-problem, which cannot be described in an analytical way. Particularly the topology changes of the corrective switching generate a problem of large dimension. Problems of this kind can be solved by evolution strategies. Because of the discrete decision variables of the topology, a special adapted evolution strategy has been developed. The paper presents the method and the mathematical model of the approach. The efficiency and functionality of the proposed solution method are studied at exemplary results of realistic test systems