Timo Isermann

In future electrical distribution systems, component heterogeneity and their cyber‐physical interactions through electrical lines and communication lead to emergent system behavior. As the distribution systems represent the largest part of an energy system with respect to the number of nodes and components, large‐scale studies of their emergent behavior are vital for the development of decentralized control strategies. This paper presents and evaluates DistAIX, a novel agent‐based modeling and simulation tool to conduct such studies. The major novelty is a parallelization of the entire model—including the power system, communication system, control, and all interactions—using processes instead of threads. Thereby, a distribution of the simulation to multiple computing nodes with a distributed memory architecture becomes possible. This makes DistAIX scalable and allows the inclusion of as many processing units in the simulation as desired. The scalability of DistAIX is demonstrated by simulations of large‐scale scenarios. Additionally, the capability of observing emergent behavior is demonstrated for an exemplary distribution grid with a large number of interacting components.

The constantly increasing number of controllable components in the distribution grid calls for scalable and robust control approaches making use of the components' capabilities for the wellbeing of the grid. This paper presents the concept of SwarmGrid control where swarms of components emerge to determine control decisions in a distributed manner. Knowledge of the global system state is not required for the distributed decision making. The underlying architecture is based on a Multi-Agent System. To generically prove the effectiveness of SwarmGrid control, its application to a typical German distribution grid consisting of 177 nodes with a total of 313 connected components is investigated by the means of co-simulation. The results suggest that SwarmGrid control has a promising impact on voltage stability, loss reduction, and the efficient integration of distributed energy resources into the distribution grid operation.

Today's vehicles are much more than a simple transportation device. Additional functionality such as navigation, automatic parking, and distance control has fundamentally increased the vehicles technological complexity. All these new functionalities are supported by outdated energy, and information and communications technology (ICT) systems, based on a multitude of independent and complex systems controlled by several different management units. As these systems dominate in fuel-powered vehicles nowadays, they are adopted and used again in the newly developed electric vehicles (EV). With the background of building highly energy efficient future EVs, a new integrated approach for controlling these systems is introduced.

Testing of wind energy converters (WEC) at ground level in contrast to an in-field setup has increased in the last years. As it is an approach which is fundamentally different to in field-testing, it requires significant modifications of the measurement environment and the layout of the sensor system. To increase the reliability of WECs, a detailed investigation of the status of various electrical and mechanical values is necessary because good condition monitoring guarantees a well-controlled state of the turbine in the desired point of operation. This leads to an appropriate maintenance strategy that enhances the lifetime of the WEC. Crucial physical values can be identified easier at ground level testing than with an in-field setup. This article addresses the realization of Hardware in the Loop (HIL) concepts on signal and power level for the use in WEC nacelle testing. Moreover, the functionality of the 1 MW demonstrator test bench operating in HIL mode with a DUT controlled by the original nacelle controller is shown.

This publication presents a practical experience in implementing fault ride through investigations on a multiphysics power hardware in the loop platform for wind turbine nacelles. Next to the aim of doing full-scale system investigations with the nacelle, the use for system certification is included in the planning. While it is quite clear that such an approach would bring significant advantages compared with in-field testing, it is also important to understand if it is possible to overcome all the challenges from a practical and, in particular, measurement point of view that system level test bench certification implies. This question is analyzed with the support a unique platform developed by the authors in collaboration with other researchers of RWTH Aachen University. The platform is able to support test activities up to 1 MW.

This paper presents a practical experience in implementing Fault Ride Through investigations on a multi-physics Power Hardware in the Loop platform for wind turbine nacelles. Next to the aim of doing full-scale system investigations with the nacelle, the use for system certification is included in the planning. While it is quite clear that such an approach would bring significant advantages compared to in-field testing, it is also important to understand if it is possible to overcome all the challenges from a practical and, in particular, measurement point of view that system level test bench certification implies. This question is analyzed with the support a unique platform developed by the authors in collaboration with other researchers of RWTH Aachen University. The platform is able to support test activities up to 1-MW.

This paper describes a test bench for wind turbine nacelles enabling system level investigations. It is equipped with an electrical and a mechanical Power Hardware in the Loop (PHIL) interface emulating the behavior of the electrical power grid and the wind field, respectively. A nacelle test bench offers the possibility to speed up the certification process for wind turbines as the regular testing procedure takes place outside, and therefore strongly depends on the weather conditions. The paper describes the motivation for the test bench as well as the advantages of such a setup and its PHIL interfaces to the Real Time Simulators. First results are given as the test bench has just been commissioned. Furthermore, the paper introduces the main approach for the process of building a 1:1 scale test setup for wind turbines.

Against the background of the increasing amount of distributed generation and the intention of local utilities to offer system services at the distribution level, a high degree of automation gets more and more necessary. Right now DG sources already are able to offer system services although these potentials often remain unused. Local utilities face these new challenges by applying energy management systems which essentially need information on the system state. Unfortunately, measurement is sparsely spread in distribution grids so the required data normally cannot be provided. The authors propose a new approach on managing distribution systems based on adaptive agents which are placed at different locations on the grid. They are able to locally control sources, loads and switches to keep the system state within tolerable bounds. In doing so, knowledge of the entire grid state becomes obsolete. For this purpose a decentralized power flow method is introduced. Depending on available local information each agent is able to calculate a system state. By communicating their results other agents can now react adequately. Furthermore, it is possible to infer on the entire system state as well.

Nowadays, local utilizes face new challenges by operating their grids. This is mainly due to the increasing amount of distributed generation in the low and medium voltage level. If the injected power is not consummated locally but has to be transmitted over a long distance, voltages at busbars close to the source will rise which on the one hand is a potential threat to the equipment and on the other hand may lead to illegal system states and outages. Furthermore, measurement is sparsely spread in distribution grids. Thus, the grid state is not entirely observable and violations may not be detected. So local utilities trying to achieve a highly automated energy supply do not aim at a global governor but the grid has to be controlled locally using small adaptive systems which are able to make decisions autonomously. In this paper a new approach on the exploitation of reactive power reserves of inverter dominated distributed sources is introduced. Although X/R ratio differs from the transmission system reactive power offers a constricted but cost-effective possibility to control nodal voltages. So, first, a method to control single nodal voltages by using reactive power reserves of inverters is presented. After that, voltage stability is improved by intelligent agents which are able to work together.