Optimal transmission access for generators in wind-integrated power systems: stochastic and robust programming approaches
Integrating wind generation in power systems has raised the issue of optimal transmission access for generators. The available transmission capacity for a generator is now subject to the uncertain wind generation. Therefore, the need for a transmission access mechanism has emerged. This study proposes three different optimisation models for calculating transmission access under uncertain wind generation. First, it develops a mathematical model to find the expected transmission access. A chance-constrained optimisation model is derived to find different levels of access to the transmission network with pre-specified reliability levels. The chance-constrained model provides detailed information regarding the available transmission access at different reliability levels. This gives options to a connecting generator regarding its choice of transmission access. Finally, a robust model for transmission access is proposed. The robust model provides the conservative transmission access which is assured against all future realisations of wind generation. The proposed expected, chance-constrained and robust approaches for optimal transmission access are numerically studied using an illustrative 2-bus example and the IEEE 30-bus and IEEE 300-bus case studies. The moment-matching technique is used to generate wind and demand scenarios. The numerical results show the utility of three derived models to calculate the optimal transmission access for generators.