Assessing potential benefits of dynamic frequency restoration reserve dimensioning in multi-area power systems

This article investigates the potential benefits of dynamic Frequency Restoration Reserve (FRR) allocation and dimensioning in a multi-area context, focusing on the Nordic Load-Frequency Control block. Emphasis is placed on how the available information impacts the FRR dimensioning. To assess the potential benefits, a model for multi-area FRR dimensioning is proposed, applicable to both static and dynamic dimensioning approaches. The proposed FRR dimensioning model includes a new application of a methodology to simulate imbalance scenarios and sequentially dimensions FRR capacity for reference incidents and normal imbalances. The main benefit of dynamic FRR dimensioning is that the need for FRR capacity is continuously updated according to the expected short-term operating conditions, such that the daily reliability level is always close to the desired reliability level. Case study results show that dynamic FRR dimensioning can lead to a reduction in total reserve needs compared to a static approach. This reduction is significantly larger if FRR is dimensioned after the clearing of the day-ahead market.