AC contingency dispatch based on security-constrained unit commitment

In this paper, an effective ac corrective/preventive contingency dispatch over a 24-h period is proposed based on security-constrained unit commitment (SCUC) model. The SCUC model includes unit commitment, ac security-constrained optimal power flow (SCOPF), and load shedding (LS) for steady state and contingencies. The objective of this SCUC model is to obtain the minimum bid-based system operating cost while maintaining the system security. The prevailing generation constraints, such as hourly power demand, system reserves, fuel and emission limits, ramp up/down limits, and minimum up/down time limits, are included in this model. In addition, system constraints such as time-limited emergency controls for a given contingency and ac network security limits are taken into account. The proposed ac solution for the hourly scheduling of generating units is based on Benders decomposition. Case studies with the six-bus system, the IEEE 118-bus test system, and 1168-bus system are presented in detail in this paper.