Security-constrained optimal coordination of generation and transmission maintenance outage scheduling

The proposed approach to the optimal coordination of midterm planning can be used by vertically integrated utilities as well as the ISOs in electricity markets. The approach coordinates the optimal maintenance scheduling of generating units and transmission lines, within the outage scheduling horizon of weeks to months, with the security-constrained unit commitment of available components. The proposed model provides hourly schedules for maintenance outages, generation unit commitment, and transmission flows based on hourly load curves. In addition, the approach calculates the optimal allocation of fuel and emission allowance for thermal units in a vertically integrated utility, and energy allocation in electricity markets. This paper discusses that a seamless coordination of midterm and short-term optimization schemes will effectively improve the security of electricity services and reduce the chance of blackouts in aging power systems. The proposed approach highlights a trade-off between calculation speed and accuracy for large-scale implementations. A six-bus system is used for detailed analyses, and further results presented for the IEEE-118 system exhibit the effectiveness of the proposed midterm planning approach. Index Terms--Lagrangian relaxation, maintenance outage scheduling for generators and transmission lines, mixed integer programming, resource allocation and utilization, transmission network security, unit commitment.