Characteristic Optimal Power Flow in AC Power Networks with High Penetrations of Intermittent Power Sources

Due to the increasing integration of intermittent power sources (IPSs, such as wind and solar power sources) into AC power networks, an accurate and efficient time-varying optimal power flow (OPF) is required with the corresponding dispatch control system. From the power balancing perspective, traditional dispatch control system consists of short-term (day-ahead) scheduling and Automatic Generation Control (AGC). However, due to the integrated large-scale IPS uncertainties, the real-time dispatch has to be employed into the power balancing process, thus a new dispatch control system with high penetrations of IPSs is proposed in this paper. To achieve optimal generation schedules in different dispatch levels, it is necessary to implement OPF as an optimization tool. Tradition OPF only guarantees system's optimality on a single snapshot but not through the entire time period, especially for power networks with high penetrations of IPSs. Therefore, a characteristic OPF that ensures the system's economic efficiency and security over an entire time period is further proposed in this paper, in which the median snapshot is considered as objective function and two terminal snapshots are considered as constraints. Simulation case studies on a modified IEEE 118-bus system demonstrate the effectiveness and efficiency of the proposed characteristic OPF.