Benefits of coordinated control reserve activation and grid management — A probabilistic load flow analysis

Joint control reserve procurement and activation by several Transmission System Operators can have significant technical and economic benefits. In congested transmission networks, however, the activation of control reserve can be constrained by impending overloads. In this paper the benefits of an optimization to coordinate control reserve activation and grid management considering uncertainties caused by forecast errors is outlined. The effect of these uncertainties are measured by using probabilistic load flow methods based on convolution technique. A joint optimization is presented to minimize the costs of supplying control reserve and conducting redispatch, taking into account HVDC lines, variable costs of power plants and the impact of control reserve activation on lines instead of optimizing it separately as it is the current proceeding by European Transmission System Operators. In addition, a method to determine the solution space for permissible control reserve distributions is presented. In a case study of the German transmission grid for the year 2024 the costs of the joint optimization are contrasted to the costs using the normal merit order and additional redispatch as it is the current market scheme. With the simulation for one year, the solution spaces are calculated to show, which power plants can supply control reserve in every hour without causing redispatch measures and whether the existing power plants in 2024 are sufficient to provide control reserve activation without impending overloads.