Instantaneous reserve by battery energy storage systems – a holistic system model to analyze the dynamic power system interactions

The electrical power system is facing an increasing share of distributed generation from renewable energy sources compared to conventional power plants with declining system inertia. Thus, ancillary services such as frequency containment by instantaneous frequency reserve has to be provided by new market players. Battery energy storage systems (BESS) offer rapid response capabilities, making them a favorable choice for enhancing power system stability. However, a wide variety of battery types are available, requiring careful selection based on specific applications. Full system simulations are essential for the delineation of the requirements for batteries to be able to provide instantaneous back-up. This paper examines the system aspects of battery energy storage systems consisting of a converter powered by a battery. In order to investigate the battery system requirements from a power system perspective, a new holistic system model has been developed that includes detailed representations of the dynamic power system, the converter and the battery model. Employing the converter control technique of a virtual synchronous generator (VSG) the so parameterized BESS acts from grid viewpoint like a conventional synchronous generator providing system inertia. The validation of the converter and battery models, together with their parameterization, has been carried out through comparable experimental setups. Different scenarios have been developed and simulated to identify the parameters of the virtual synchronous machine for optimized frequency stabilization and to determine the corresponding load on the converter and battery. The results obtained, such as the weekly energy throughput of 1 P nom h o u r based on real grid data, provide quantitative indicators for the design and optimization of BESS for use as VSG for the first time. The results were used to identify suitable battery system configurations for providing instantaneous back-up. Further analysis of the power demand characteristics reveals that only 4 % of the BESS capacity is utilized for instantaneous reserve providing options for multi-use business concepts. • Coupled simulation workflow from battery to grid response. • Evaluation of virtual synchronous generator (VSG) parameters on system behavior. • Analysis of power and energy demand for battery provided instantaneous reserve. • Definition of the requirements for BESS for provision of instantaneous reserve.