Aggregation of the ancillary service potentials of the distribution system level at multiple vertical system interfaces in the context of hierarchical multi-level grid control strategies

电力系统的过渡导致分散式能源（DER）的大规模整合，特别是在配电网中，以及导致输电网中的大型火电厂的临时位移，从而降低其辅助服务潜力。这导致越来越多的成本密集型再调度措施，并需要在未来的电网扩展措施。相比之下，配电系统运营商（DSO）可以利用DER和电能存储系统的辅助服务潜力，因为分布式有功和无功功率的灵活性可以根据需求进行控制。这些灵活性潜力可由DSO用于优化其自身的系统操作以及用于向更高级别的系统运营商（例如，传输系统运营商（TSO））提供辅助服务潜力。在垂直系统界面上加强TSO/DSO和DSO/DSO的相互作用是必要的，以便在不同的系统层次上利用这些灵活性潜力。为此，分层多级网格控制策略代表了合适的概念。分层方法是基于在单个系统接口处DSO系统的所有分布式灵活性潜力聚合到对应的有功和无功功率灵活性区域（PQ多边形），即所谓的可行操作区域（FOR）。FOR表示DSO在特定操作点内调整垂直有功和无功功率流的灵活性潜力。在TSO的业务管理中，在FOR的限制范围内确定下级系统所需的灵活性需求，并将其传达给DSO。因此，在级联过程的框架内，可以在垂直TSO/DSO或DSO/DSO系统接口处向更高级别的系统运营商提供分布式灵活性潜力，以确保整个系统的稳定性。目前文献中讨论的确定FOR的方法仅适用于单个垂直系统界面。在多个垂直系统界面的情况下，例如在TSO和DSO之间，由于网格结构，界面变量之间出现复杂的垂直和水平依赖性。因此，在接口总线的FO之间也存在相应的依赖性。拟议的研究项目的目标是开发的方法和程序的灵活性提供DER的灵活性潜力的聚合在较低级别的系统在多个垂直系统接口的多维FO。第二个目标是在分层多级网格控制策略的背景下，在更高级别的系统运营商的运营管理中实现这些多维FO。

The transition of the electric power system results in a massive integration of decentralized energy resources (DER), especially in the distribution grids, as well as to a temporary displacement of large thermal power plants in the transmission grids with a resulting reduction of their ancillary service potentials. This leads to an increasing number of e.g. cost-intensive redispatch measures and to a need for grid expansion measures in the future. In contrast, the distribution system operators (DSOs) have access to the ancillary service potentials of the DER and electrical energy storage systems as distributed active and reactive power flexibilities that can be controlled according to demand. These flexibility potentials can be used by the DSOs to optimize their own system operation as well as for the provision of ancillary service potentials to the higher-level system operator, e.g. a transmission system operator (TSO). An intensification of TSO/DSO- and DSO/DSO-interactions at the vertical system interfaces is necessary to enable the use of these flexibility potentials in the different system levels. For this purpose, hierarchical multi-level grid control strategies represent a suitable concept. Hierarchical approaches are based on the aggregation of all distributed flexibility potentials of a DSOs system at a single system interface to a corresponding active and reactive power flexibility region (PQ-polygon), the so-called Feasible Operation Region (FOR). The FOR represents the flexibility potentials of the DSO for adjusting the vertical active and reactive power flows within a specific operating point. Within the operational management of the TSO the flexibility demand required from the lower-level system is determined within the limits of the FOR and communicated to the DSO. Within the framework of a cascading process, distributed flexibility potentials can thus be made available to the higher-level system operators at the vertical TSO/DSO- or DSO/DSO-system interfaces to ensure the stability of the overall system. Methods for the determination of the FOR discussed in literature so far are only applicable for a single vertical system interface. In the case of multiple vertical system interfaces, e.g. between a TSO and a DSO, complex vertical and horizontal dependencies between the interface variables arise due to the meshed grid structure. Thus, there are also corresponding dependencies between the FORs of the interface busses. The objective of the proposed research project is the development of methods and procedures for the aggregation of the flexibility potentials of flexibility-providing DER in lower-level systems at multiple vertical system interfaces as multidimensional FORs. A second objective is the implementation of these multidimensional FORs in the operational management of the higher-level system operator in the context of hierarchical multi-level grid control strategies.