Kari Mäki

Kari Mäki


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 July 2015 in Systems
Verified
Journal Article
Open access
PDF file
JLJuhani Latvakoski
Juhani Latvakoski
KMKari Mäki
Kari Mäki
JRJussi Ronkainen
Jussi Ronkainen
JJJukka Julku
Jukka Julku
JKJani Koivusaari
Jani Koivusaari
Modern society is facing great challenges due to pollution and increased carbon dioxide (CO2) emissions. As part of solving these challenges, the use of renewable energy sources and electric vehicles (EVs) is rapidly increasing. However, increased dynamics have triggered problems in balancing energy supply and consumption demand in the power systems. The resulting uncertainty and unpredictability of energy production, consumption, and management of peak loads has caused an increase in costs for energy market actors. Therefore, the means for studying the balancing of local smart grids with EVs is a starting point for this paper. The main contribution is a simulation-based approach which was developed to enable the study of the balancing of local distribution grids with EV batteries in a cost-efficient manner. The simulation-based approach is applied to enable the execution of a distributed system with the simulation of a local distribution grid, including a number of charging stations and EVs. A simulation system has been constructed to support the simulation-based approach. The evaluation has been carried out by executing the scenario related to balancing local distribution grids with EV batteries in a step-by-step manner. The evaluation results indicate that the simulation-based approach is able to facilitate the evaluation of smart grid– and EV-related communication protocols, control algorithms for charging, and functionalities of local distribution grids as part of a complex, critical cyber-physical system. In addition, the simulation system is able to incorporate advanced methods for monitoring, controlling, tracking, and modeling behavior. The simulation model of the local distribution grid can be executed with the smart control of charging and discharging powers of the EVs according to the load situation in the local distribution grid. The resulting simulation system can be applied to the study of balancing local smart grids with EV batteries. Based on the evaluation results, it is estimated that the simulation-based approach can provide an essential, safe, and cost-efficient method for the evaluation of complex, critical cyber-physical systems, such as smart grids.

17 March 2017 in ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part B. Mechanical Engineering
Verified
Journal Article
Closed access
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KFKim Forssén
Kim Forssén
KMKari Mäki
Kari Mäki
MRMinna Räikkönen
Minna Räikkönen
RMRiitta Molarius
Riitta Molarius
Extreme weather forms a major threat to electricity distribution networks and has caused many severe power outages in the past. A reliable electrical grid is something most of us take for granted, but storms, heavy snowfall, and other effects of extreme weather continue to cause disruptions in electricity supply. This paper contributes to ensuring the continuity of electricity supply under adverse weather events. The aim is to describe and to analyze how the continuity of electricity supply can be ensured in the case of extreme weather. Based on the research, the energy sector is highly dependent on the existing locations and structures of the current infrastructure. Aging infrastructure is commonly seen as a main vulnerability factor. The most vulnerable parts of the electricity distribution system to extreme weather conditions are the networks built as overhead lines. However, the resilience of the networks against extreme weather can be increased significantly in all phases of a disaster management cycle. Methods and technological solutions proposed in this paper to alleviate such problems include adjacent forest management and periodic aerial inspections, situational awareness, distributed generation and microgrids, placement of overhead lines, underground cabling, and unmanned air vehicles. However, it must be noticed that the methods and their value for stakeholders are context-dependent. Thus, their applicability and appropriateness may change over time.

19 October 2017 in Infrastructures
Verified
Journal Article
Open access
PDF file
MRMinna Räikkönen
Minna Räikkönen
RMRiitta Molarius
Riitta Molarius
KMKari Mäki
Kari Mäki
KFKim Forssén
Kim Forssén
PPPeter Petiet
Peter Petiet
ANAlbert Nieuwenhuijs
Albert Nieuwenhuijs
The resilience of critical infrastructure (CI) to extreme weather events (EWE) is one of the most demanding challenges for all stakeholders in modern society. Although partial risk reduction is feasible through the introduction and implementation of various risk mitigation measures (RMM), decision-makers at all decision-making levels are pressured to find ways to cope with the impending extreme weather and to have a thorough understanding of the EWE impacts on CI. This paper discusses how the value of RMMs can be created and assessed in a stakeholder network. Qualitative research methods, namely literature review and AHP (Analytic Hierarchy Process), were applied as research methods. The paper examines how disaster management and value creation both converge and differ from each other. It also presents a case study on the value of various RMM and the impacts of extreme winter conditions on electricity distribution in Finland. Based on the case study, the most important value criterion was the benefits of the RMM in economic, social, and environmental terms. At a fundamental level, the value of RMM should be expressed not only in terms of money but also in regard to safety, security, societal acceptability, CI dependability, and other typically intangible criteria. Moreover, the results reveal that the interrelationship of value creation and disaster management offers new insights to both approaches.

12 June 2020
Verified
Book Chapter
Open access
PDF file
KMKari Mäki
Kari Mäki
AKA. Kulmala
A. Kulmala
KHK. Heussen
K. Heussen
OGO. Gehrke
O. Gehrke
ERE. Rikos
E. Rikos
PKP. Kotsampopoulos
P. Kotsampopoulos
Selected validation scenarios and corresponding test cases in the context of the ERIGrid project are presented in this chapter. Furthermore, the benefits of using the ERIGrid validation method and testing tools are discussed on the realized system validation examples.