Power systems security analysis

Due to the deregulation consequences (economical imperatives and technical difficulties), the electric power systems operate nowadays close to the security limits. In order to protect the grid against severe contingencies and to increase the security margins, the transmission systems operators have to take special measures. These actions are based on security analysis. Present paper proposes a cyclic security analysis methodology which checks the static, the dynamic and the transient behavior of a given power system. The proposed methodology is able to establish if a certain operating point is secure by taking into account the possible contingencies