Volume 73, Issue 11 - Special Issue: Optimierter Netzbetrieb im Übertragungs- und Verteilnetz (OptiNet); Guest Editors: Martin Wolter and Dirk Westermann

Increasing requirements for transmission capacity and delays in grid expansion lead to rising costs for congestion management (CM). Approaches to better utilize the existing infrastructure and reduce costly redispatch are being examined, such as curative congestion management (CCM), in which remedial actions (RAs) are only triggered post-fault. Although CCM has the potential to reduce CM costs, it raises concerns about possibly heightened operational risks. As failures of curative RAs can endanger grid operation, it is crucial to account for possible RA failures already at the planning stage and thus increase the reliability of CCM by redundancy. This paper presents three concepts to provide redundancy for CCM, ensuring that no limit violations occur even if a single curative RA fails. A mixed-integer linear program (MILP) is used to optimize preventive and curative RAs while accounting for operational limits and the defined redundancy requirement. Annual simulations on a benchmark grid model compare the effectiveness of these concepts in terms of cost-efficiency. The practicability and indications of the influence on grid security are analyzed qualitatively. The results show that concepts with active or passive partial redundancy preserve most of the economic benefits of CCM, whereas complete replacements of multiple RAs entail higher complexity and costs.

The short-term procurement of reactive power is becoming increasingly important, calling for more intensive coordination between grid operators due to local optimization challenges. The German congestion management instrument Redispatch 2.0 provides a platform for such coordination processes. This paper presents an approach and first field test results for extending Redispatch 2.0 by reactive power to provide it from the distribution grid at the point of common coupling to use it for voltage stability in the transmission grid. The results show the potential of expansion and at the same time the challenges that arise in terms of reliable reactive power provision.

In this study, the increasing dynamics of the power system are analyzed and modeled using a laboratory demonstrator. The demonstrator integrates a real-time simulator, advanced control unit, state-of-the-art communication standards and infrastructure, as well as a connection to commercial control center software via programming interface. This setup facilitates the testing of modern system operation strategies, including curative system operation and wide area protection and control. The objective is to develop a comprehensive system that combines hardware and software to closely replicate field deployed systems. By accurately simulating communication paths and functionalities, the demonstrator enables the evaluation of innovative system operation methods under realistic conditions. The structure is detailed, compared to real systems and current research, highlighting unique features: modern communication technologies, interfaces to control room software, and modular expandability. This modularity supports research on simulation, control units, intelligent electric devices (IEDs), data transmission, and system operation, tested individually before overall system validation.

Wide-area monitoring, protection, and control (WAMPAC) systems are essential for ensuring stability in modern electric power grids with large shares of converter-based renewable generation. Laboratory environments allow risk-free validation before field deployment. Building on our Control Center Laboratory and Real-Time Simulation (CLARO) framework, we implement complete WAMPAC workflows that couple real-time grid simulation (Opal-RT), standardized communication protocols (IEEE C37.118, IEC 61850, IEC 60870-5-104, Modbus), and modern information-technology/operational-technology (IT/OT) architectures (Apache Kafka, Kubernetes, containerization). A real-time automation controller executes corrective actions using Generic Object Oriented Substation Event (GOOSE) messages based on a pre-computed catalog of measures. On a synthetic 118-bus benchmark, phasor-measurement-unit (PMU) driven end-to-end delays from disturbance to control action remain below 250 ms, while PMU-enhanced state estimation reduces bus-voltage magnitude error by over 40 % compared with Supervisory Control and Data Acquisition (SCADA) only. These results demonstrate the feasibility of realistic, lab-based WAMPAC validation and highlight how integrating modern IT/OT stacks strengthens grid resilience.

Zusammenfassung Das kurative Engpassmanagement ermöglicht es, Stromversorgungssysteme näher an ihren Betriebsgrenzen zu betreiben. Dieser Artikel analysiert die Online-Berechnung temporärer thermischer Grenzwerte für Freileitungen und erläutert einen Anwendungsfall für kurative Maßnahmen unter Verwendung von Netzkuppeltransformatoren zwischen Verteil- und Übertragungsnetzen.