Matti Lehtonen's research while affiliated with Aalto University and other places

Publications (565)

Article
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The ongoing rapid increase in the integration of variable and uncertain renewable energy sources calls for enhancing the ways of providing flexibility to power grids. To this end, we propose an optimal approach for utilizing electric vehicle parking lots to provide flexibility at the distribution level. Accordingly, we present a day-ahead schedulin...
Article
Emergence of reformation and privatization in energy systems has caused the development of multi-agent distribution systems. In this context, each agent as an independent entity aims to efficiently operate its respective resources; while, the distribution network operator (DNO) strives to control the grid in an efficient and reliable manner. Respec...
Article
This paper presents an original approach for the evaluation of reliability of active distribution networks with unknown topology. Built upon novel reformulations of conventional definitions for distribution reliability indices, the dependence of system-oriented reliability metrics on network topology is explicitly formulated using a set of mixed-in...
Article
This paper proposes strategic biddings for a consumer demand that participates in both the day-ahead and balancing markets. The strategic behavior of the consumer is represented by the bilevel optimization programming with minimization of consumer costs at the upper level (UL) subject to the co-optimization of energy and reserve in the market clear...
Article
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Recently, the proliferation of distributed generation (DG) has been intensively increased in distribution systems worldwide. In distributed systems, DGs and utility‐owned electric vehicle (EV) to grid aggregators have to be efficiently scaled for cost‐effective network operation. Accordingly, with the penetration of power systems, demand response (...
Article
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Restructuring in power systems has resulted in the development of microgrids (MGs) as entities that could be operated in grid-connected or islanded modes while managing the operation of their systems. On the other hand, privatization and integration of independently operated distributed resources in energy systems have caused the introduction of mu...
Article
This paper proposes a novel bi-level strategic energy trading framework to minimize the operation cost of the distribution network (DN) interacting with peer-to-peer (P2P) transactive energy hubs with electric vehicles. A distribution system operator at the upper level minimizes its total cost from purchasing electricity in the wholesale market, ge...
Article
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Increasing the intermittent outputs of renewable energy sources (RESs) has forced planners to define a new concept named flexibility. In this regard, some short‐ and long‐term solutions, such as transmission expansion planning (TEP) and energy storage systems (ESSs) have been suggested to improve the flexibility amount. A proper optimization proced...
Article
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This paper presents a new framework for island formation prior to windstorms, which considers tree-caused failures of distribution networks. In the proposed framework, both direct and indirect effects of windstorms on distribution lines are quantified. Thus, a novel discrete Markov chain model is proposed for representing the failure modes of tr...
Article
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The present article describes a smart wireless online device for the severity monitoring of the contaminated insulators of high voltage transmission networks. Accordingly, the wireless developed monitor works by continuously sensing the magnitudes of the leakage current bursts and calculating its average root-mean-square (RMS) value at every second...
Article
This paper presents a fault detection, localization, and categorization (FDLC) method in PV fed DC-Microgrid (DCMG) with a single voltage sensor. The proposed technique is based on five statements drawn from the analysis of Line to Line (L-L) and Line to Ground (L-G) faults in different parts of the microgrid (MG). These faults may occur at any Nan...
Article
Currently, distribution systems are continuously evolving towards modern and flexible structures while integrating promising renewable energy resources (RERs). In this regard, an optimal network constraint-based expansion planning model combined with an optimal integration framework of intermittent RERs is proposed in this work to improve the topol...
Article
Nowadays, the increasing integration of variable renewable energies (VREs) in power systems have resulted in operational transformations of energy systems. Respectively, the high-amount of integrated VREs could cause severe-ramping in the net-load of energy systems due to abrupt changes in their power production. Accordingly, based on the limited f...
Article
The volatile nature of the electricity market prices and renewable resources imposes remarkable challenges for multi-energy systems operators to make the appropriate decisions. Therefore, this paper offers a linear max–min–max robust optimization-based decision-making tool that incorporates both uncertainties of the electricity market price and the...
Article
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The complexity of the design of the protection system using directional over current relays, for modern power distribution systems has been increased due to the looped/meshed operation and the penetration of distributed generations. Finding a reliable and efficient protection scheme that can be easily implemented in these distribution systems is a...
Article
The electric and magnetic fields of overhead high voltage transmission lines are still a critical problem for new construction because of their biological effects on the human body. This issue has been a subject of scientific interest and public concern for the risk of the electric and magnetic fields on living organisms. Accordingly, the overhead...
Article
This paper proposes an optimal allocation of a Wind-Storage Unit (WSU). Since transmission lines congestion varies according to the size, the location, and the operation of a generation unit in power systems, we assess the optimal location of a unit as a function of its variable operating condition. An independently operated wind-storage unit is as...
Article
This paper presents a new bi-level multi-objective model to valorize the microgrid (MG) flexibility based on flexible power management system. It considers the presence of renewable and flexibility resources including demand response program (DRP), energy storage system and integrated unit of electric spring with electric vehicles (EVs) parking (IU...
Article
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This paper introduces a new intelligent integration between an IoT platform and deep learning neural network (DNN) algorithm for the online monitoring of computer numerical control (CNC) machines. The proposed infrastructure is utilized for monitoring the cutting process while maintaining the cutting stability of CNC machines in order to ensure eff...
Article
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Worldwide, electrostatic precipitators (ESP) have been extensively utilized to separate fine particles for diverse large-scale industrial applications. In this regard, this paper presents a novel approach for modeling the dust-loaded ESP on the fine computational domain where the need for a fast solver arises. Unlike the previously published numeri...
Article
During the recent years, the power system has entered a new technological era. The trends associated with increased commitment to wind farms (WFs) and energy storage systems (ESSs) as well demand side flexibility require disruptive changes in the existing power system structures and procedures. Being at the heart of a paradigm shift from passive us...
Article
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Electricity demand forecast is necessary for power systems' operation scheduling and management. However, power consumption is uncertain and depends on several factors. Moreover, since the onset of covid-19, the electricity consumption pattern went through significant changes across the globe, which made the forecasting demand more challenging. Thi...
Article
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Designing transactive energy (TE) markets in distribution systems has been a hot topic due to the increased presence of residential prosumers. In the literature, several residential market platforms have been proposed, however, they usually have two main drawbacks as: i) ignoring the effect of single-phase distributed energy resources (DERs) on the...
Article
The distribution of the power transformers at a far distance from the electrical plants represents the main challenge against the diagnosis of the transformer status. This paper introduces a new integration of an Internet of Things (IoT) architecture with deep learning against cyberattacks for online monitoring of the power transformer status. A de...
Article
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Transformer oil insulation level may be deteriorated due to electrical and thermal faults, which may lead to transformer failure and system outage. In this regard, the first part of this paper presents comprehensive maintenance for power transformers aiming to diagnose transformer faults more accurately. Specifically, it aims to identify incipient...
Article
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Renewable energy sources have recently been integrated into microgrids that are in turn connected to electric vehicle (EV) charging stations. In this regard, the optimal planning of microgrids is challenging with such uncertain generation and stochastic charging/ discharging EV models. To achieve such ambitious goals, the best sites and sizes of ph...
Article
Full-text available
The electric and magnetic fields of overhead high voltage transmission lines are still a critical problem for new construction because of their biological effects on the human body. This issue has been a subject of scientific interest and public concern for the risk of the electric and magnetic fields on living organisms. Accordingly, the overhead...
Article
Full-text available
By taking subsidies out of the picture, wind farm operators (WFO) face new challenges to participate in electricity markets. While conventional producers benefit from dispatchable generation, wind farms with stochastic nature have a challenging job to compete with these players in the market and need to come up with alternative solutions. To this e...
Article
The privatization of distribution systems has resulted in the development of multiple-microgrid (multiple-MG) systems where each microgrid independently operates its local resources. Moreover, the high integration of independent distributed energy sources could lead to operational issues such as grid congestion in future distribution systems. There...
Article
Electric vehicle aggregator (EVAGG) is an independent entity that facilitates exchanging electricity between electric vehicles (EVs) and the grid. Energy hub (EH) is another independent entity playing a remarkable role in enhancing the efficiency, flexibility, and reliability of multi-energy systems. Although interacting between various agents is b...
Article
The aggressive goal of having a 100% renewable energy system requires preparing an appropriate infrastructure for deploying as much distributed generation (DG) as possible into the electricity network. This article aims at proposing a new framework to maximize the hosting capacity (HC) of DGs in a distribution network. This operation-planning frame...
Article
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Recently, renewable energy sources (RESs) have increasingly being integrated into the power grids as a result of environmental and governmental perspectives. In this regard, installation of RESs as potential power resources in distribution systems would benefit the grid by decreasing the power losses, as well as addressing the fossil fuel shortages...
Chapter
Introduction and development of the smart city concept require significant transformations of conventional energy systems from the structure and operational and planning aspects. In this respect, distribution systems would be designed as multi-agent systems, where each agent strives to maximize its profit. In this context, the conventional operatio...
Article
In this paper, the resilient-constrained generation and transmission expansion planning (RCGTEP) considering natural disasters such as earthquake and flood is presented. The proposed model contains a two objective problem that the first objective function minimizes the construction and operation costs of resiliency sources (RSs) and, in the second...
Article
High frequency transformer model represents a mandatory requirement to study transient performance of distribution systems under lightning strokes. In Finland, the distribution systems are frequently subjected to these strokes. In this paper, an accurate and simple model is introduced for the distribution transformers concerning two-port network im...
Article
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The rapid employment of photovoltaic (PV) has highlighted the importance of accurate solar irradiance forecasting in grid operation. However, the intermittent nature of solar irradiance represents a big challenge and degrades the accuracy of forecasting techniques, posing towards developing ensemble-based approaches. Most ensemble approaches genera...
Conference Paper
Regarding the weaknesses accounted for the centralized distribution state estimation (DSE), proposing decentralized formulations have been remarked in large distribution systems. However, predefined network division is usually assumed in the previous work and the effect of zone size (or the number of network zones) on the performance of the multi-a...
Conference Paper
As a result of the current restructuring procedure in power systems, renewable energy sources (RESs) are increasingly integrated into distribution systems. Respectively, while, the installation of RESs would benefit the system by securing the power supply, decreasing the power losses, and addressing the environmental concerns; their high penetratio...
Preprint
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This e-companion provides detailed information on the bi-level reformulation containing the KKT condition and linearization techniques as well as the linearization of bi-product arisen from binary and continuous variables.
Article
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In this paper, a new family of ultra-high step-up DC-DC converters based on a center-tapped coupled inductor (CI) is proposed. These single-switch converters employ different inductive and capacitive power transfer techniques by utilizing multi-winding CIs, intermediate capacitor links and simple switched-capacitors to improve the transferred power...
Article
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Abstract Power systems have been undergoing significant restructuring as a result of increasing independently operated local resources. Consequently, new entities, i.e. microgrids (MGs), are developed, which facilitate the integration of local resources, specifically renewable energy sources (RESs), into the operation of power systems. Despite many...
Article
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This paper presents an intensive measurement and analysis of monopolar ionized fields in bundled high voltage direct current (HVDC) conductors using the finite difference method based on the full multigrid technique. The positive feature of this study is that it considers the comprehensive representation of the bundle conductor, unlike the existing...
Article
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The growing importance of Microgrid in future power systems highlights critical challenges like microgrid control and stability. An islanded microgrid including distributed generations (DG), energy storage systems (ESS), and different types of loads (static or dynamic) is prone to instability. The whole microgrid system must be analyzed and designe...
Article
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This paper presents a novel optimization model for the flexible-reliable operation (FRO) of energy hubs (EHs) in electricity, natural gas, and district heating networks. To achieve flexible EH in the presence of renewable energy sources (RESs) and combined heat and power (CHP) system, energy storage systems (ESS) and incentive-based demand response...
Article
Soil conductivity and permittivity have a substantial influence on lightning-electromagnetic transients in power system. In this paper, lightning-induced voltages are computed on a multi-conductor overhead line due to nearby first and subsequent return strokes. Besides, this study considers the longitudinal complex inductance of the line due to the...
Article
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In recent years, with increasing the penetration of renewable-based distributed generation (DGs), voltage control plays a vital role in operating distribution systems (DS). Furthermore, the traditional voltage control devices are not fast enough to regulate the voltage due to transient events and the intermittent characteristics of renewable energy...
Article
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Lately, the European Union has reinforced the targets set to cut back carbon emissions. The energy generation sector and particularly, the district heating (DH) system, is still prevailed by combustion of fossil fuels that heavily contributes to such emissions. This paper presents a system-based approach to study the coupling between electricity an...
Conference Paper
Floodwater can severely damage electricity distribution system (DS) components and interrupt the service to all the customers, even the critical ones. Thus, it is necessary to evaluate the possible impacts of a flooding event on DS operation. This paper proposes a new framework that constructs islands prior to flood occurrence, for continuatio...
Article
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In recent years, the internet of things (IoT) represents the main core of Industry 4.0 for cyber-physic systems (CPS) in order to improve the industrial environment. Accordingly, the application of IoT and CPS has been expanded in applied electrical systems and machines. However, cybersecurity represents the main challenge of the implementation of...
Article
Lately, the integration of renewable energy sources (e.g., photovoltaic and wind generation systems) has been raised into microgrids interconnected with plug-in electric vehicles (PEVs). Such intermittent generation and charging/discharging PEV profiles are challenging to ensure the secure and optimal operation of microgrids. In this article, an op...
Article
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Introducing new technologies in co-generation and tri-generation systems has led to a rapid growth toward the energy hubs (EHs) as an effective way for coupling among various energy types. On the other hand, the energy systems have usually been exposed to uncertain environments due to the presence of renewable energy sources (RESs) and interaction...
Article
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Optimal power flow (OPF), a mathematical programming problem extending power flow relationships, is one of the essential tools in the operation and control of power grids. To name but a few, the primary goals of OPF are to meet system demand at minimum production cost, minimum emission, and minimum voltage deviation. Being at the heart of power sys...
Article
Introduction of renewable energy sources (RESs) and independently operated multi-microgrid (MMG) systems have led to new issues in the management of power systems. In this context, uncertainty associated with RESs as well as intense ramps inflicted on the network called system flexibility constraints have raised new challenges in power systems. The...
Article
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Resilient design of robust multi-objectives PID controllers via the D-decomposition method is presented in this paper for automatic voltage regulators (AVRs). The stabilizing interval of derivative gain (kd) is analytically calculated by the Routh-Hurwitz criterion. The kp – ki domain, for a fixed value of kd, is decomposed in root invariant region...