Security constrained economic dispatch of wind-integrated power system considering optimal system state selection

The increasing penetration of wind power makes it a critical problem to maintain the security and economy in power system operations. This study proposes a security constrained economic dispatch (SCED) strategy that considers optimising system state selection and spinning reserve allocation. The system state selection is judged by the criterion of occurrence probability. Considering the impacts of wind power integration on the outage probability of system component, the over-current protection outage model and voltage protection outage model are employed to calculate the operational outage probabilities of transmission lines and generators, respectively. The fast sorting technique is adopted to select all system states with higher-occurrence probability than the system security threshold. Besides the traditional constraints on system demand and regulation range, the spinning reserve allocation additionally obeys the transmission constraints in the selected states to avoid transmission congestion in contingency situations. Benders decomposition is utilised to partition the SCED problem into the active power dispatch sub-problem and the optimal reserve allocation sub-problem for tractability. A numerical comparison with the traditional N-1 security assessment SCED is given to validate security and economic improvement of the proposed method.