Marko Delimar

Marko Delimar
University of Zagreb · Faculty of Electrical Engineering and Computing (FER)

PhD

About

65
Publications
6,400
Reads
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781
Citations
Citations since 2016
18 Research Items
581 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Introduction
Marko Delimar is a professor at University of Zagreb Faculty of Electrical Engineering and Computing, where he has been with the Department of Energy and Power Systems since 1997. His interests include electric power and energy systems, simulations and modelling, intelligent systems, and engineering education. His current research focuses on analysis and design of smart grid architectures and large-scale integration of renewable energy sources.
Additional affiliations
October 2014 - September 2018
University of Zagreb Faculty of Electrical Engineering and Computing
Position
  • Head of Faculty

Publications

Publications (65)
Article
The volatility and complex forecasting methods of fluctuating wind generation is a growing issue. From a system perspective, this introduces additional issues regarding demand and supply balancing and also creates the need for more balancing capacity. One of the best supplements to volatile wind nature is certainly hydro generation, especially in c...
Article
Full-text available
E-Mails: perica.ilak@fer.hr (P.I.); marko.delimar@fer.hr (M.D.); slavko.krajcar@fer.hr (S.K.) Abstract: This paper proposes a coexistence model for two independent companies both operating hydropower plants in the same river flow, based on a case study of the Cetina river basin in Croatia. Companies are participants of the day-ahead electricity mar...
Conference Paper
In the search for a more sustainable energy supply, renewable energy sources are increasingly introduced into the power system. However, most of these sources are located far from the load centers, and the existing power system is getting overloaded. A supergrid is by many seen as a viable solution that allows a massive integration of these renewab...
Article
The theoretical part describes basic power flow methods Gauss-Seidel and Newton-Raphson in their practical forms for solving a load flow problem. In practical part, IEEE test 24, 48 and 72 node networks are used to compare basic methods in terms of calculation speed: on execution of one iteration, entire calculation and on given accuracy influence....
Article
Increasing application of power electronics devices (inverter-based generation and storage, HVDC lines, FACTS devices), facilitated by growing renewable energy integration, has also changed the ac grid modeling features. Namely, the incorporation of fast-acting control devices can lead to possible detrimental interactions that appear at much higher...
Article
Full-text available
The world’s demand for electrical energy is increasing rapidly while the use of fossil fuels is getting limited more and more by energy policies and the need for reducing the impact of climate change. New sources of energy are required to fulfill the world’s demand for electricity and they are currently found in renewable sources of energy, especia...
Article
Like many other European countries, Croatia is also missing a systematic and adequate policy framework to tackle the problem of energy poverty. Currently, there is no distinction between energy and general poverty in Croatian legislation, and direct payments of utility bills are the only measure of help to (energy) poor households. Local and nation...
Article
The increasing number of flexible ac transmission systems (FACTS) and high voltage direct current (HVDC) systems is changing perspectives on small-signal stability in ac grids, as traditional steady-state modeling does not allow representing higher-frequency interactions between synchronous generators, ac grid and power electronic-based devices. Si...
Article
Full-text available
Voltage Source Converter based High Voltage Direct Current (VSC HVDC) technology is used more and more in modern power systems. Consequently, in the ac network, an increasing number of converters are appearing in mutual electrical proximity, thus forming Multi-Infeed (MI)-HVDC systems. For VSC technology, several aspects of MI-HVDC system operation...
Article
Full-text available
The development in distributed energy resources technology has led to a significant amount of non-linear power electronics converters to be integrated in the power system. Although this leads to a more sustainable system, it also can have adverse impacts on system stability and energy power quality. More importantly, the majority of the distributio...
Article
Full-text available
In competitive power markets, electric utilities, power producers, and traders are exposed to increased risks caused by electricity price volatility. The growing reliance on renewable sources and their dependence on weather, nuclear uncertainty, market coupling, and global financial instability are contributing to the importance of accurate electri...
Chapter
Over the past few years, large-scale utilization of renewable energy sources together with the high penetration of low-to-medium voltage dc sources into the generation mix of energy networks have increased attention toward deployment of dc microgrids for improving system operation, reducing environmental footprints, mitigating congestion and power...
Article
Full-text available
This study analyzes the short-run hydro generation scheduling for the wind power differences from the contracted schedule. The approach for construction of the joint short-run marginal cost curve for the hydro-wind coordinated generation is proposed and applied on the real example. This joint short-run marginal cost curve is important for its parti...
Preprint
Full-text available
This study analyses the short-run hydro generation scheduling for the wind power differences from the contracted schedule. The approach for construction of the joint short-run marginal cost curve for the hydro-wind coordinated generation is proposed and applied on the real example. This joint short-run marginal cost (SRMC) curve is important for it...
Article
Due to the fast development of renewable energy systems and the severe limitations enforced by the Marine Pollution Protocol, the utilizing of wind turbines, solar generation, sea wave energy and energy storage systems in marine vessel power systems has been attracting a lot of attention. Hence, a marine vessel power system with Photovoltaic (PV),...
Article
Full-text available
Multi-terminal Direct Current Transmission (MTDC) is an emerging and promising technology for the transmission of electricity and the main initiator of the development of MTDC grids is offshore wind generation. However, prior to their construction, a thorough investigation of different aspects of their implementation and operation is required. In t...
Conference Paper
A sequential search strategy for the control variable subset selection, used for optimal power system voltage control and reactive power management, is presented in this paper. The objective of the presented selection method is to eliminate the redundant control variables which have small impact on the reactive power optimization (RPO) objective fu...
Article
This article summarizes the efforts of European network operators to adopt a holistic approach to their research and innovation (R&I) activities. Transmission system operators (TSOs) in Europe represented by ENTSO-E and distribution system operators (DSOs) represented by EDSO-SG, as well as organizations such as European Technology Platform Smart G...
Conference Paper
This paper presents a method of reactive power optimization based on partitioning of the power system daily load curve. The underlining problem that is being solved is the optimization of elements with defined maximum allowable daily operating times (MADOT). The daily load curve of the power system was partitioned into 24 stationary states which we...
Article
Full-text available
Accurate forecasting tools are essential in the operation of electric power systems, especially in deregulated electricity markets. Electricity price forecasting is necessary for all market participants to optimize their portfolios. In this paper we propose a hybrid method approach for short-term hourly electricity price forecasting. The paper comb...
Article
Full-text available
This paper analyzes a price-taker hydro generating company which participates simultaneously in day-ahead energy and ancillary services markets. An approach for deriving marginal cost curves for energy and ancillary services is proposed, taking into consideration price uncertainty and opportunity cost of water, which can later be used to determine...
Chapter
HVDC is a technology which has been used for long-distance bulk power transfer, connecting different synchronous zones or submarine connections. Lately, HVDC has experienced a revival. In Europe, this revival is being driven by the strong increase in generation from renewable energy sources, the liberalization of the energy system, and the difficul...
Conference Paper
Water is scarce resource with uncertain availability. Hence finding an optimal production schedule for hydro producer is usually a complex task and it is necessary to carefully balance the timing of water use. This paper addresses the self-scheduling problem for a price-taker hydro producer. The goal is maximizing the profit of a hydro producer thr...
Conference Paper
In today's liberalized and competitive power market, electric utilities, power producers and traders are exposed to increasing price risks and volatility. The growing reliance on renewable sources and their dependence on weather, nuclear uncertainty, market coupling and global financial instability are contributing to importance of accurate price f...
Conference Paper
Microgrid concept has been proven to have a positive impact on the operation of the power system. Distributed generation and energy storage enable control of microgrid power flow which can be optimized for participation in the electricity markets. This paper presents an optimization model for economical scheduling of a microgrid using linear progra...
Article
Full-text available
This paper describes an improved sensorless vector control strategy for a squirrel cage induction generator used in variable speed wind energy conversion systems (WECS). The main goal is to design a robust control algorithm immune to generator parameter variations. In order to estimate the rotational speed of the induction generator, a model refere...
Article
The accelerated evolution of power systems and the associated new trends, such as Smart Grids, has stimulated the development of various approaches in handling the problems of increased electricity demands, power market (de)regulation and power systems reliability. One of the new key concepts is the virtual power plant (VPP), which represents a con...
Conference Paper
Introduction to a conference proceedings.
Conference Paper
Full-text available
This paper emphasises the importance of a well planned unit commitment model in coordination with water value evaluation to achieve optimal economic results for genco. The existing water value models are examined and customized for the developed power system model. Linear programming methods are used to achieve optimal economic performance for hydr...
Conference Paper
This paper observes the rotor angle stability phenomena. Initial simulations were made on a single machine infinite bus system, to model the influence of the synchronous generator, excitation system, stabilizer and the network layout. This is later applied to the model of the Croatian power system in the year 2016, when thermal power plant Plomin 3...
Conference Paper
Load forecasting is one of the critical activities in electric power system planning. This paper presents clustering algorithms and their usage in load forecasting on a case study in Zagreb, Croatia. Load data acquisition is not always being systematically conducted in distribution networks and some data often has to be extrapolated. For such metho...
Conference Paper
Full-text available
Integracija obnovljivih izvora u elektroenergetske sustave odvija se u sve većoj mjeri zahvaljujući državnim poticajima. Najznačajnije elektrane iz skupine obnovljivih izvora svakako su vjetroelektrane, za koje u Hrvatskoj postoje brojni projekti. Međutim, loša strana velike želje za penetracijom vjetroelektrana jest relativno malo područje na koje...
Conference Paper
The biggest proportion of renewable energy investments in Europe is focused on exploitation of wind power. Due to high investors' interest, Croatian power system is experiencing a metamorphosis to a modern power system with significant wind power penetration. This paper describes optimal connection points for the large amount of wind power plants e...
Conference Paper
This paper propose improved sensorless vector control of squirrel cage induction generator for variable speed wind energy conversion system. The rotational speed of the induction generator is estimated with the Model Reference Adaptive System - MRAS observer. The estimated rotational speed is used as the feedback of the control loop in the converte...
Conference Paper
This paper compares various models of steering strategies for a portfolio of Distributed Energy Resources (DER). Virtual Power Plant (VPP) is a flexible representation of such a portfolio, and one of its key assignments is to guide each DER in order to dispatch desirable active power. Portfolio includes two controllable synchronous generators (CHP)...
Conference Paper
Full-text available
IEEEXtreme is an IEEE Student Activities Committee initiative to create a worldwide programming contest for IEEE student branches. The success of the past editions and the way IEEEXtreme is evolving, suggests that it will become the only worldwide competition capable of promoting the computer programming skills of collegiate students within a globa...
Article
The paper presents description of original biofeedback computer program called PhysioSoft. It has been designed on the basis of the experience in development of biofeedback techniques of interdisciplinary team of experts of the Department of Health Psychology of the University of Applied Health Studies, Faculty of Electrical Engineering and Computi...
Article
Full-text available
Placement of the acetabular cup during total hip arthroplasty is of great importance because usually every deviation from the ideal centre of rotation negatively influences endoprosthesis survival, polyethylene wear and hip load. Here we present hip load change in respect to various acetabular cup positions in female patients who underwent total hi...
Article
The LS DC 123 IIR algorithm, developed at Faculty of Electrical Engineering and Computing University of Zagreb, derived from the original LS IIR algorithm is discussed in the paper. The main purpose of the algorithm is digital protection relay restraint during the energisation (inrush current) of unit transformer and 100 % generator ground fault pr...
Conference Paper
Full-text available
The paper presents an analysis of a one-semester technical course ldquoElectrical facilitiesrdquo. The goal of the paper is to show how a system of real-time knowledge testing at undergraduate level, using a radio-frequency clicker system and conventional knowledge assessment methods, was implemented on a single course at the University of Zagreb....
Conference Paper
Full-text available
This paper presents a small electricity market study based on an agent-based power network simulator in deregulated conditions. A simple six node network is modelled in EMCAS to observe effects of transmission line outages and transmission congestion problems. The effects of price variations due to line outages are presented and discussed. Possible...
Conference Paper
This paper discusses the development of model sensorless vector control of induction machine used in wind turbine application. The paper presents preliminary results. Instead of wind turbine, induction machine equipped with a frequency converter is used to simulate wind behaviour. In order to estimate the shaft speed of the induction machine model...
Conference Paper
Electrical power system engineers often face a challenge of modeling power system components and performing complex calculations. This paper describes a teaching/learning process of modeling power systems networks and performing network calculations in an object-oriented environment.
Conference Paper
Significant developments occurred in the field of electric power engineering at the end of 19th century. At the time of Tesla's Niagara Falls power plant and first power systems in Europe, little is known about electric power system developments in Croatia. This paper presents historical background and activities associated with the first electric...
Conference Paper
Consideration of losses of electric energy in the transmission network is important for power system operation and control. Development of the remote control system in the Croatian National Control Centre enabled an accurate calculation of losses and their comparison with the results measured in the terminal nodes. Additional value in proposed way...
Conference Paper
In order to achieve a more secure and economic operation of a power system its state should be known not only in the present but some time ahead. Transmission system operators do not have the same security margins like they had in the past. Most of the tools of security assessment operate on-line and provide valuable input to the system operators....
Article
The paper presents the construction of a deterministic multistage simulation model with age and sex structure. The model is based on the natural history of rubella. The dynamics of rubella is described by a system of non-linear differential equations. The model was validated by simulating the course of rubella in Trešnjevka, Zagreb, from 1961 to 19...
Conference Paper
This paper presents an artificial neural network based model for identifying anomalies in the reported power system topology. The results obtained using a multilayer perceptron with backpropagation learning algorithm are presented and discussed.
Conference Paper
This is the third part of the study on using neural networks in Power system topology identification. The first two parts (Part I - Line processing and Part II - Node processing) were presented at previous IASTED PES conferences. In this paper a multiplayer percepton neural network is used to help identify the state of an unsupervised part of the p...
Conference Paper
Very often, insufficient data is exchanged between neighboring power systems for quality load flow and contingency analysis. The external systems, therefore, have to be substituted with the power system equivalents. In this paper the possibilities of using an artificial neural network as the external power system equivalent is explored, to be used...
Conference Paper
This paper presents a neural network based model for forecasting gas consumption for residential and commercial consumers. A feedforward neural network with sigmoid nodes and one hidden layer was trained by backpropagation. The model was validated on real data from a distribution area covering 7% of the total consumption in Croatia, consisting most...
Conference Paper
Solving Ax=b, where A is a sparse matrix, is a frequent engineering problem; however, in power transmission system calculations A is among the sparsest matrices in all engineering problems. Over the years a large number of software packages have been developed to handle operations with large sparse matrices (BLAS, LAPAK, LINPAK, LAPAK++, SparseLib+...
Conference Paper
Neighboring powers systems often do not exchange enough data for quality load flow and contingency analysis within a single system. This is why external systems often have to be substituted with their equivalents. This paper explores the possibilities of using an artificial neural network as the external power system equivalent for the purposes of...
Conference Paper
The development of computer technology enabled significant improvements in dispatching centers. That was especially important for Croatian Electricity that was faced with a prospect of a new way of operation with new functions and responsibilities. The financial situation did not allow complete replacement of the computer system and its software su...
Conference Paper
The paper presents an evaluation of the ATP-EMTP in power system protection. A simulation model of an actual power plant and substation were created and short circuits were simulated. The analysis of results is given and compared with actual results of the real measurements
Article
Currents and voltages of the power system are not only dependent on the elements of the power system, but also on the loads that are being connected onto the system. The aim of this article is to present two-phase load modelling and it's implementation to the Newton-Raphson method for calculation of the three-phase load flow. The program, based on...
Article
The well-established power flow methods (Gauss-Seidel, Newton-Raphson, and Fast-Decoupled) are all based on classical methodologies of applied mathematics. Classical computer programs for solving the power flow based on these methods have been in practical use for a relatively long number of years. All of these programs met with strict limitations...
Conference Paper
Assessing statistical significance of correlation between distance matrices is difficult due to problems arising from nonlinearily of relationships and interdependencies between pairwise distances in each matrix. Quadratic assignment procedure is a valid permutation test of association between matrices. The power and the size of the standard t-test...

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