Frequency stability analysis of Smart Balancing scenarios in Germany

Abstract:
The concept of smart balancing (SB) encourages balancing responsible parties (BRPs) to react to system imbalance data published by the transmission system operator (TSO). While this approach aims at reducing control area imbalances and associated costs for frequency restoration reserve (FRR) activation by incentivising BRPs to deviate from their schedule, it can potentially deteriorate frequency stability. This study utilizes a single busbar dynamic simulation model of the synchronous area of Continental Europe, including a detailed German control area model and an aggregated rest. The work assesses the system frequency stability and the SB design parameter influence on it. The parameters allow for modelling various scenarios for FRR pricing, balancing energy price calculation and publication of different types of near real-time (NRT) control area imbalance. The scenarios consider the publication of NRT data by TSOs as exact values or after data binning. Regarding the FRR pricing mechanism, both single and combined pricing approaches are considered. To generate simulation results, data from 2019 was used and three periods were analysed to display different power imbalance cases. The results indicate that the integration of SB in the German control area could have a negative impact on system frequency quality, depending on the details of the NRT data provision and on the assumptions related to the BRP behaviour. NRT data binning leads to lower but constant SB power, preventing steep frequency changes. In contrast, exact NRT data publication leads to high and sudden SB activation, causing higher frequency response amplitudes.