K. Strunz

K. Strunz
Technische Universität Berlin | TUB · Department of Energy and Automation Technology

Dr.-Ing.

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179
Publications
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6,310
Citations

Publications

Publications (179)
Article
Full-text available
An analytical model for transient stability assessment of hybrid AC–DC transmission systems is formulated, implemented, and validated. The equal‐area criterion, as known from the transient stability analysis of AC power systems, is redeveloped for AC–DC power systems using high‐voltage direct current (HVDC) transmission based on the voltage sourced...
Article
Full-text available
The accurate prediction and simulation of thermal transients in district heating networks is essential for the meaningful analysis of combined heat and power systems. For this purpose, the focus of this paper lies on the development of a consistent and comprehensive modelling framework that links diverse pipe model categories to specific applicatio...
Article
Distributed generation (DG) based on synchronverter with no battery is unable to provide frequency support without compromising DC-bus voltage level. However, this paper proposes a new synchronverter, which can outline this limitation by adjusting the DC-bus voltage setpoint if the grid frequency gets out of a safe predefined range. This is done th...
Article
The voltage margin control strategy is often used for multi-terminal high voltage direct current (MTDC) transmission systems. It ensures a tight regulation of DC voltage similarly to the master–slave and sharing of voltage regulation task between two or more stations similar to the voltage droop, therefore combining desired features of those contro...
Article
Full-text available
Electromagnetic transient programs (EMTPs) are widely used for simulating electromagnetic transient in power systems. With the increasing interest in integrated energy system (IES), it would be beneficial to extend the scope of EMTP‐type application to multi‐physics transients in integrated electrical and gas networks. An efficient and accurate mod...
Article
Full-text available
An analytical model for the half-bridge submodule based modular multilevel converter (MMC) under pole-to-pole fault is formulated, implemented, and validated. The events after the fault occurrence are categorized into four stages, and the equivalent circuit of each stage is derived. A generic equivalent circuit is developed respectively for the ana...
Article
The impact of microgrid applications expands with the increasing share of renewable energy resources in the energy supply and the progressing electrification of the transport sector. The additional energy demand of electric vehicles (EVs) may cause increased peak loads, leading to growing burdens on the power system. In this regard, microgrids allo...
Article
A large-scale integration of wind and solar energy relies on a grid that allows for the renewable electric power to securely reach the load centers. While the necessity for the extension of transmission capacity to obtain a climate-friendly and sustainable overall energy system is given by physical evidence, the realization of any extension relies...
Article
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The paper examines a number of methods for extracting dynamic phasors from samples of natural waveforms that are generated using electromagnetic transient (EMT) simulators. It delves into the theory underlying each phasor extraction method and the numerical routines used for their implementation. The paper performs an in-depth analysis of the prope...
Article
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Control design and stability analysis of direct-driven permanent magnet synchronous generator (PMSG)-based wind energy conversion systems (WECSs) typically involve extensive time-domain simulations and frequency-domain analyses. Those studies rely on accurate and computationally efficient models of WECSs. Detailed switching models can accurately de...
Article
This paper proposes a novel multi-scale cable model in phase-coordinates exploiting the fully-coupled structure of the nodal admittance matrix instead of using the conventional approach based on the Method of Characteristics (MoC). The usage of the admittance modeling allows a straightforward representation of cables regardless of their lengths as...
Article
An integrated generation, transmission, and energy storage planning model accounting for short-term constraints and long-term uncertainty is proposed. The model allows to accurately quantify the value of flexibility options in renewable power systems by representing short-term operation through the unit commitment constraints. Long-term uncertainty...
Chapter
Dieses Kapitel beleuchtet die Markt- und Systemintegration von E-Mobilität und zeigt, neben aktuellen Praxisanwendungen, zukünftige Ansätze zur Systemoptimierung in intelligenten Energieversorgungsnetzen auf. Die Gestaltung einer kostengünstigen, nachhaltigen und versorgungssicheren Energieversorgung inklusive Mobilität ist dabei die hauptausschlag...
Article
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The structural mass of a building provides inherent thermal storage capability. Through sector coupling, the building mass can provide additional flexibility to the electric power system, using, for instance, combined heat and power plants or power-to-heat. In this work, a mathematical model of building inertia thermal energy storage (BITES) for in...
Article
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Abstract Digitalisation is seen to have contributed to the demise of 50% of the Fortune 500 companies since 2000. The large electric motor segment is not immune to this changing business landscape and must evolve to survive. This sector is experiencing declining revenues as traditional hardware‐sales‐focused business models have proved inadequate t...
Article
Full-text available
The behavior of constant power loads is known to be a potential cause of instability in DC microgrids. This issue is addressed by the DC microgrid stabilizer proposed in this paper. It relies on active stabilization through power electronic control by introducing a virtual positive resistance to counteract the negative incremental resistance of a c...
Article
In the above article [1] , due to a production error, Table I was duplicated. The correct Table II is given below: (see table attached)
Article
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Power hardware-in-the-loop (PHIL) technology allows for the testing of physical equipment in a real-time simulation environment. An important role is attributed to the power interface. This power interface connects a power system model, which is implemented on a digital computer, to physical hardware under test, such as a power electronic converter...
Article
Full-text available
Power system stability is widely assessed based on tools that rely on the representation of voltages and currents through quasi-static phasor calculus, implying that the network itself and the synchronous machine stators are modeled by algebraic equations. Accordingly, the associated fast transients are ne-glected, assuming those decay rapidly. How...
Article
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This paper presents a novel multi-rate algorithm for co-simulation of power system transients using base-frequency dynamic phasors for adaptive simulation of transients (BFAST) and electromagnetic transients (EMT) solvers. The BFAST solver alters its solution technique from dynamic phasors to EMT based upon the frequency contents of the waveforms b...
Article
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A simulation tool for modeling harmonic propagation in low voltage distribution networks with manifold nonlinear equipment is developed. The tool is based on a hybrid domain approach representing each nonlinear household device with accurate and fast white box model and the supply network - with the harmonic admittance matrix in the frequency domai...
Conference Paper
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High voltage direct current (HVDC) systems are an alternative for transmission of energy with higher efficiency and lower electrical losses over long distances. HVDC systems have become more common with the evolution of power electronics, promoting the interest of research in power flow control techniques. The main objective of this paper is to per...
Article
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Digital simulators of electric networks have been indispensable tools for engineers and researchers engaged in the analysis and design of electric power and energy systems. With the increasing interest to extend electric energy toward multi-energy systems covering multiple energy carriers, there arises a need to also extend the capabilities of toda...
Article
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Wind power is a clean and widely deployed alternative to reducing our dependence on fossil fuel power generation. Under this trend, more turbines will be installed in wind farms. However, the inspection of the turbines in an offshore wind farm is a challenging task because of the harsh environment (e.g., rough sea, strong wind, and so on) that lead...
Article
This paper proposes a one-terminal traveling wave (TW)-based transmission line earth fault distance protection function. It only needs the detection of the first incident modal earth fault-induced TWs, i.e., the challenging detection of wavefronts reflected from the fault point is not required. Both the sampling frequency effect and inaccuracies on...
Article
This paper presents a novel algorithm for online identification of the Thévenin equivalent parameters in ac three–phase power grids of inductive nature. One unique property of the algorithm is to ensure convergence of the estimated parameters within finite time, provided that a weak excitation condition—necessary for identifying offline parameters—...
Article
The papers in this special section examine modeling and simulation methods for the analysis and design of advanced energy conversion systems. Energy conversion lies aEnergyveral fronts including materials, conversion methods, power electronics, and controls have created new opportunities for efficient energy conversion from both the conventional an...
Article
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A multi-scale transients model of a doubly fed induction generator (DFIG)-based wind energy conversion system (WECS) is developed, implemented, and validated. All ac circuit and control quantities of the electrical part are modeled by analytic signals rather than just real signals. In addition to the real parts, the analytic signals also comprise o...
Article
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A novel criterion for quantifying the resilience of power systems supplying data centres is formulated to measure the system's ability to sustain functionality even during an outage. By comparative analysis of two alternative data centre power systems covering apparatus of electrical power supply and environmental control, it is shown that reliabil...
Article
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In this paper, a novel distribution system state estimation method based on the information provided by smart meters to support coordinated voltage control strategies in real time is presented. Because the measurement redundancy in a distribution system is very low compared with the transmission system, the proposed method is able to mitigate the e...
Article
Full-text available
An efficient and accurate multi-scale induction machine model for simulating diverse transients in power systems is developed and validated. Electrical variables are described through analytic signals that consist of real in-phase and imaginary quadrature components, covering only positive frequencies of the Fourier spectrum. The stator is modeled...
Article
Multi-energy systems (MES) involving networks of different energy carriers can support the balancing of fluctuating renewable generation by coordinated joint operation. In this paper, an object-oriented modeling methodology for planning and operations control of MES based on nodal analysis is proposed. The framework provides the modularity to simul...
Conference Paper
This paper deals with the operational integration of electric buses and charging infrastructure conducted in field tests. Relevant actors and entities for managing the charging processes are introduced and the main interactions described. Further, an overview of available charging infrastructures and acquisition equipment used in field sites is det...
Article
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This article provides a unique benchmark to integrate and systematically evaluate advanced functionalities of microgrid and downstream device controllers. The article describes Banshee, a real-life power distribution network. It also details a real-time controller hardware-in-the-loop (HIL) prototyping platform to test the responses of the controll...
Article
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A methodology for enlarging the region of attraction (ROA) of a DC microgrid with constant power loads (CPLs) is proposed. The enlargement is achieved through the optimal design of a polynomial droop controller. The design of this nonlinear controller is done by solving a sum of squares (SOS) program. The proposed SOS program allows finding a Lyapu...
Article
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Recent developments in renewable energy and Information Technology (IT) fields made it easier to set up power systems at a smaller scale. This proved to be a turning point for developing First-Access Electricity Systems for the underserved locations around the world. However, there are planning and operation challenges due to lack of past data on s...
Article
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Microgrids that enable peer-to-peer energy exchange represent an important enabling technology for scaling renewable energy. Furthermore, peer-to-peer microgrids are an essential ingredient of the swarm electrification approach, facilitating the modular growth of infrastructure for energy access in the developing world. However, peer-to-peer microg...
Article
In this paper, a new synchronous machine model is developed for EMTP-type simulations. The stator circuit is expressed in the abc phase domain. The machine model is represented as a Norton equivalent with a current source in parallel with a constant Norton admittance. The machine equations are reformulated so that the computational effort required...
Article
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For the purpose of utilizing electric bus fleets in metropolitan areas and with regard to providing active energy management at depots, a profound understanding of the transactions between the market entities involved in the charging process is given. The paper examines sophisticated charging strategies with energy procurements in joint market oper...
Article
Full-text available
Analogies between electric, hydraulic, and thermal quantities do exist for developing various circuit models that involve quantities such as currents and voltages, flow rates and pressures, and heat transfers and temperatures. With the increasing interest in multi-carrier energy systems, it would be beneficial to extend the scope of analogies to th...
Article
Full-text available
The integration of photovoltaic (PV) modules into DC microgrids relies on the capabilities of maximum power point (MPP) tracking and output voltage regulation (OVR). Under partial shading or mismatches between PV submodules, accurate global MPP tracking and efficient OVR are challenging processes. For global MPP tracking, distributed MPP tracking i...
Conference Paper
Full-text available
In order to explore possible solutions for smart grid applications, the integration of a uni-and bidirectional charging infrastructure for the operation of an electric bus is investigated and partly demonstrated. The established infrastructure is used to charge a bus battery or to feed electrical energy into the power system. Necessary components w...
Article
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In order to overcome challenges associated with the integration of distributed energy resources (DER) into state-of-the-art and future power grids require the development of a common basis for testing using appropriate benchmark systems. Real-time hardware-in-the-loop (HIL) simulation has proven to be an advanced and efficient tool for the analysis...
Article
In this paper, a multi-scale induction machine model for the simulation of diverse transients in power systems is developed in the dq0 domain. The proposed model includes main flux saturation. The equations that describe the electrical performance of the induction machine are represented through analytic signals whose Fourier spectrum can be shifte...
Article
Power hardware-in-the-loop (PHIL) technology allows for the testing of physical equipment including power electronic converters in a simulation environment that closely mirrors the reality of the electric power grid. A challenge involved in PHIL systems is the design of the interface between digital network model and physical equipment as this has...
Article
Full-text available
The strive for efficient and cost-effective photovoltaic systems motivated the power electronic design developed here. The work resulted in a DC-DC converter for module integration and distributed maximum power point tracking (MPPT) with a novel adaptive control scheme. The latter is essential for the combined features of high energy efficiency and...
Conference Paper
Full-text available
For the purpose of utilizing electrified bus fleets in metropolitan areas and with regards to provide an active energy management at intra-urban depot, a profound understanding of the transactions between the market entities involved in the charging process is given. Sophisticated charging strategies with energy procurements in joint market operati...
Conference Paper
As a higher share of electric energy is generated by fluctuating renewable resources, multi-energy systems and their storage capabilities are of growing importance. Quantifying the potential of those multi-energy systems, appropriate analysis tools are required. Due to different energy carriers, new aspects are relevant for analysis. Besides the el...
Article
Full-text available
Microgrids are subsystems of the distribution grid operating as a single controllable system either connected or isolated from the grid. In this paper, a novel cooperative Model Predictive Control (MPC) framework is proposed for urban districts comprising multiple microgrids sharing certain Distributed Energy Resources (DERs). The operation of the...
Article
A virtual power plant (VPP) is formulated and developed as a service-centric aggregator that enables the market integration of distributed energy resources and simultaneously supports co-operation with the distribution system operator (DSO) in addressing the issue of network usage. A suitable schedule of interactions and communications between aggr...
Article
Full-text available
Programs of the EMTP (Electromagnetic Transients Program) type have been the most popular digital simulators for emulating electromagnetic transients in power electric networks consisting mainly of rotating machinery, lines, transformers, loads, and power electronic converters. With the increasing interest in fuel cells, it would be beneficial to e...
Article
A frequency-dependent transmission line model for multi-scale simulation of diverse transients over a wide range of frequencies is developed, implemented, and validated. It makes use of the concept of frequency-adaptive simulation of transients in which the Fourier spectra are adaptively shifted in the frequency domain to reduce the discretization...
Book
This book contains the results of the research project „komDRIVE“. The project analyzed the substitution potential of commercial transport vehicles with internal combustion engines by electric vehicles for different economic sectors in urban agglomerations. Based on this analysis the effects of electrical vehicle fleets on electrical nets were inve...
Conference Paper
Full-text available
In this paper, a medium voltage (MV) benchmark network model as a tool to perform research in distributed energy resources (DER) integration is introduced. This paper takes the North American medium voltage benchmark model introduced in the CIGRE Task Force C06.04.02 as the basis and refines the model to an extent so that it represents MV distribut...
Conference Paper
Full-text available
This paper evaluates the benefits derived from demand flexibility from the DSO perspective. It presents various simulations in the network of Evora, considering different scenarios for load, generation and the network capacity. Moreover, for each scenario business cases are developed for the provision of the customer flexibility as a service to the...