Robust allocation of reserves considering different reserve types and the flexibility from HVDC

Since the production of electric power from renewable resources is intrinsically variable and uncertain, it creates difficulties in balancing demand and generation. On the one hand, the ensemble of dispatchable resources is being required to provide larger and more frequent ramping capabilities. On the other hand, the transmission grid is operated closer to its limits on a more frequent basis. These two factors require a reassessment of the techniques used to provide and ensure the deliverability of reserves and flexibility. In this study the authors present an adjustable robust approach for the procurement of reserve, as well as for the repartition of this reserve between manual and policy-based automatic reserves. This approach takes into consideration the location and temporal evolution of the uncertainty on the generation sources and the flexibility offered by high voltage direct current (HVDC) interconnections. The resulting problem is solved iteratively. Case studies compare policy and non-policy based reserves, the allocation of ramping capacity and the resulting operational cost.