• Energy Research

Environmental concerns and policy directives coupled with renewable energy penetration targets in Europe and United States are leading to a greater need for identifying technical and economic characteristics that facilitate the integration of electric vehicles (EVs) in the electricity network. An important step in mitigating instability associated with unregulated EV charging and renewable power feed‐in is the integration of EVs as providers of load frequency control (LFC). This study presents an evaluation of six European and North American LFC systems on the basis of EV characteristics to identify suitability for EV integration. The evaluation shows that the Eastern Denmark network is most feasible for frequency containment and restoration reserve using EVs.

There is an increasing amount of renewable energies in Europe as well as in other regions. Some of this energy is generated more centralized than with conventional power plants (offshore wind farms) and some is more decentralized (distribution grids). However renewable energy generation is not uniformly distributed over all Europe. A meshed HVDC Overlay grid is a suitable solution to transmit this power to centers of load. With renewable energy and load forecasts it is possible to calculate an optimal schedule for those HVDC converters. This paper presents a mixed AC/DC optimal power flow and a method which enables the HVDC grid to participate in unpredictable power flow changes between schedules. Those can be caused e.g. by load frequency control events.

For domestic customers the tariff structure for purchasing electrical energy has emerged rapidly with the broad deployment of smart metering. Yet, most market retailers are uncertain, which products address consumers most, since the market for electricity is known to have little elasticity. This publication presents the final analysis on the RESIDENS field trail and reports on the consequences of introducing a Time-of Use Tariff to an existing market. The findings are derived from real load profiles and demonstrate the possibility and willingness of domestic customers to align their consumption behavior to external requirements. A market segmentation has been carried out to show how different types of customers react to ToU-tariffs. Finally, the price elasticity was analyzed, before and after applying a ToU-tariff. This publication profits due to its interdisciplinary character both from social and power engineering knowledge.

A real-time development platform for simulation studies of control and operation of the next generation of power system control functions is introduced. The platform covers all aspects of the challenges of future power system requirements related to operation and control. In this paper, the requirements of a simulation platform will be formulated. A laboratory setup with special attention to the utilization of real-time simulation equipment and some typical reference applications will be described.

Zusammenfassung Dieser Beitrag widmet sich der Analyse der Auswirkungen von Preissignalen auf das Verbrauchsverhalten von Haushaltsstromkunden. Er schlägt einen systematischen Auswerteprozess vor, der die Datenvorverarbeitung, verschiedene Aggregationsschritte, die Analyse mit Clusterverfahren (für preisbeeinflusste Typtage bei einzelnen oder aggregierten Haushalten) und die Analyse einzelner Abtastzeitpunkte umfasst. Dieser Auswerteprozess wird auf den Olympic Peninsula Project Datensatz angewendet.

The synthesis of the structure of the power system stabiliser (PSS) and its parametrization are based entirely on methods of linear system theory. Thus the desired effect of the PSS is limited to a bounded area around one system operating point. The use of a controller based on fuzzy set theory introduces an event controlled excitation of the synchronous machine taking into account the power system operation. The desired response of the fuzzy controller is given by a set of rules which are obtained from the limits of the voltage regulator and the undesired performance of the conventional excitation control. A fuzzy controller has been developed for which simulation results are provided. These results support the concept of a fuzzy controller for the purpose of excitation control. They show that a well designed fuzzy controller is superior to a fast excitation control with an additional PSS. >

Zusammenfassung In diesem Beitrag wird ein hierarchischer Ansatz zum optimalen Einsatz von stationären elektrischen Energiespeichern unter besonderer Beachtung des hybriden Speicherkonzeptes vorgestellt. An Hand eines Praxisbeispiels wird die Vorgehensweise beim Entwurf und der Implementierung einer Betriebsführungslösung für hybride Speichersysteme dargestellt und erste Ergebnisse präsentiert.

Abstract Emerging real-time applications in information technology, and operational technology enable new innovative concepts to design and operate cyber-physical systems. A promising approach, which has been discovered recently as key technology by several industries is the Digital Twin (DT) concept. A DT connects the virtual representation of a physical object, system or process by available information and sensor data streams, which allows to gather new information about the system it mirrors by applying analytic functions. Thereby the DT technology can help to fill sensor data gaps, e. g., to support anomaly detection, and to predict future operating conditions and system states. This paper discusses a dynamic power system DT as a cornerstone instance of a new generation of EMS, and a prospective new EMS architecture, to support the increasingly complex operation of electric power systems. Unlike in traditional offline power system models, the parameters are updated dynamically using measurement information from the supervisory control and data acquisition (SCADA) and a wide area monitoring system (WAMS) to tune the model. This allows to derive a highly accurate virtual representation of the mirrored physical objects. A simulation engine, the Digital Dynamic Mirror (DDM) is introduced, in order to be able to reproduce the state of a reference network in real-time. The validation of the approach is carried out by a case study. In a closed loop within EMS applications, the DDM can help to assess contingency mitigation strategies, thus it can support the decision-making process under variable system conditions. The next generation of control centre Energy Management System (EMS) can benefit from this development by augmentation of the dynamic observability, and the rise of operator situation awareness.

The percentage of electricity produced by renewable energy sources grows rapidly during last years. But high-power renewable energy sources like offshore or onshore wind farms in coastal regions are located very often far from consumers. The task of the energy transport over long distances becomes more and more important. Due to the difficulties finding new corridors for the extra high voltage (EHV) transmission lines in densely populated countries with developed infrastructure is often recommended to combine the new transmission line with other infrastructure objects like railways, highways and other transmission lines. One of theoretical possibilities is the use of common pylons for the installation of a new EHV transmission line together with catenary of electrified railway lines. Another one is the laying of HVDC cable parallel to the rail line. The proximity of different current feeding systems causes the electromagnetic interaction between transmission line and catenary. These interferences can disturb the operation of both systems. On the base of mathematical modelling of electromagnetic interferences between transmission lines and catenary the interaction between both systems is considered in the offered paper.

The intense application of Voltage Source Converter based HVDC interconnections and grids will result in a hybrid AC-HVDC-system. The operation of such a system becomes complex regarding system security and system operation. This paper describes major challenges and proposes potential solutions, including a combined security assessment, preventive optimization and curative actions. A coordination of both systems enables an efficient application of existing transport capacity. Keywords: Hybrid AC-HVDC-systems, Curative action, System security, Operational planning, System operation