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

电力系统的转型导致分散的能源(DER)的大规模整合，特别是在配电网中，以及输电网中大型火电厂的临时转移，从而降低了它们的辅助服务潜力。这导致了越来越多的重新调度措施，例如成本密集型的重新调度措施，以及未来对电网扩展措施的需求。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，作为可根据需求控制的分布式有功和无功灵活性。这些灵活性潜力可被DSO用来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。必须加强垂直系统界面上的TSO/DSO-和DSO/DSO-相互作用，以便能够在不同的系统级别上使用这些灵活性潜力。为此目的，分层多级电网控制策略代表了一个合适的概念。分层方法是基于将DSO系统在单个系统界面上的所有分布式柔性势聚集到对应的有功和无功柔性域(PQ-POLYGON)，即所谓的可行操作区(FOR)。For代表了DSO在特定运行点内调节垂直有功和无功潮流的灵活性潜力。在TSO的运行管理中，较低级别系统所需的灵活性要求在FOR的限制范围内确定，并传达给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操作员提供分布的灵活性潜力，以确保整个系统的稳定性。到目前为止，文献中讨论的确定For的方法仅适用于单个垂直系统界面。在多个垂直系统接口的情况下，例如在TSO和DSO之间，由于网状网格结构，接口变量之间出现复杂的垂直和水平依赖关系。因此，在接口总线的FOR之间也存在相应的依赖性。拟议研究项目的目标是开发在多个垂直系统接口的较低级别系统中将提供柔性的DER的灵活性潜力聚合为多维FOR的方法和程序。第二个目标是在分级多级电网控制战略的背景下，在更高级别系统操作员的操作管理中实施这些多维FOR。

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.