Online short-term reliability evaluation using a fast sorting technique

To consider time varying system operating conditions and operating reserve units, the online short-term reliability of a power system is investigated. Real-time system reliability based on the online operation data provided by the SCADA/EMS/WAMS is assessed using time- dependent state probabilities of components. Considering both speed and accuracy requirements, a fast sorting technique (FST) is proposed to quickly select the required number of system states in descending order probability. The number of computations and comparisons used in the evaluation is minimum. The relative accuracy of a given reliability index is denned as the stopping rule for the evaluation. As only a small number of system states are required to achieve the high accuracy of the short-term reliability indices when using the FST, the evaluation can be performed in an online environment. The proposed evaluation technique is illustrated by the application to the IEEE-RTS and China Southern Power Grid.