Preface to Special Issue on Planning, Operation and Control of Power Systems under New Environment of Power Industry

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

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Design and Research on Power Systems and Algorithms for Controlling Electric Underground Mining Machines Powered by Batteries

Energies ◽

10.3390/en14134060 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4060

Author(s):

Artur Kozłowski ◽

Łukasz Bołoz

Keyword(s):

Power Systems ◽

Power Supply ◽

Internal Combustion Engines ◽

Underground Mining ◽

Test Stand ◽

Research Network ◽

Control Algorithms ◽

Systems And Control ◽

And Control ◽

Supply Systems

This article discusses the work that resulted in the development of two battery-powered self-propelled electric mining machines intended for operation in the conditions of a Polish copper ore mine. Currently, the global mining industry is seeing a growing interest in battery-powered electric machines, which are replacing solutions powered by internal combustion engines. The cooperation of Mine Master, Łukasiewicz Research Network—Institute of Innovative Technologies EMAG and AGH University of Science and Technology allowed carrying out a number of works that resulted in the production of two completely new machines. In order to develop the requirements and assumptions for the designed battery-powered propulsion systems, underground tests of the existing combustion machines were carried out. Based on the results of these tests, power supply systems and control algorithms were developed and verified in a virtual environment. Next, a laboratory test stand for validating power supply systems and control algorithms was developed and constructed. The tests were aimed at checking all possible situations in which the battery gets discharged as a result of the machine’s ride or operation and when it is charged from the mine’s mains or with energy recovered during braking. Simulations of undesirable situations, such as fluctuations in the supply voltage or charging power limitation, were also carried out at the test stand. Positive test results were obtained. Finally, the power supply systems along with control algorithms were implemented and tested in the produced battery-powered machines during operational trials. The power systems and control algorithms are universal enough to be implemented in two different types of machines. Both machines were specially designed to substitute diesel machines in the conditions of a Polish ore mine. They are the lowest underground battery-powered drilling and bolting rigs with onboard chargers. The machines can also be charged by external fast battery chargers.

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Guest Editorial: Special Issue on Power Converters and Control Techniques for Very Fast Response Applications

IEEE Journal of Emerging and Selected Topics in Power Electronics ◽

10.1109/jestpe.2020.3044160 ◽

2021 ◽

Vol 9 (1) ◽

pp. 7-10

Author(s):

Diego G. Lamar ◽

Miguel Rodriguez

Keyword(s):

Guest Editorial ◽

Power Converters ◽

Fast Response ◽

Special Issue ◽

Control Techniques ◽

Editorial Special Issue ◽

And Control

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Overcapacity Risk of China’s Coal Power Industry: A Comprehensive Assessment and Driving Factors

Sustainability ◽

10.3390/su13031426 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1426

Author(s):

Delu Wang ◽

Xun Xue ◽

Yadong Wang

Keyword(s):

Evaluation Model ◽

Supply And Demand ◽

Correlation Effect ◽

Power Industry ◽

Environmental Benefits ◽

Risk Level ◽

Correlation Based Feature Selection ◽

Coal Power ◽

And Control ◽

The Impact

The comprehensive and accurate monitoring of coal power overcapacity is the key link and an important foundation for the prevention and control of overcapacity. The previous research fails to fully consider the impact of the industry correlation effect; making it difficult to reflect the state of overcapacity accurately. In this paper; we comprehensively consider the fundamentals; supply; demand; economic and environmental performance of the coal power industry and its upstream; downstream; competitive; and complementary industries to construct an index system for assessing coal power overcapacity risk. Besides; a new evaluation model based on a correlation-based feature selection-association rules-data envelopment analysis (CFS-ARs-DEA) integrated algorithm is proposed by using a data-driven model. The results show that from 2008 to 2017; the risk of coal power overcapacity in China presented a cyclical feature of “decline-rise-decline”, and the risk level has remained high in recent years. In addition to the impact of supply and demand; the environmental benefits and fundamentals of related industries also have a significant impact on coal power overcapacity. Therefore; it is necessary to monitor and govern coal power overcapacity from the overall perspective of the industrial network, and coordinate the advancement of environmental protection and overcapacity control.

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Exploring ‘digital placemaking’

Convergence The International Journal of Research into New Media Technologies ◽

10.1177/13548565211014828 ◽

2021 ◽

Vol 27 (3) ◽

pp. 573-578

Author(s):

Germaine Halegoua ◽

Erika Polson

Keyword(s):

Digital Media ◽

Sense Of Place ◽

Media Use ◽

Special Issue ◽

Social Actors ◽

Broad Framework ◽

The Many ◽

And Control ◽

Connected Spaces

This brief essay introduces the special issue on the topic of ‘digital placemaking’ – a concept describing the use of digital media to create a sense of place for oneself and/or others. As a broad framework that encompasses a variety of practices used to create emotional attachments to place through digital media use, digital placemaking can be examined across a variety of domains. The concept acknowledges that, at its core, a drive to create and control a sense of place is understood as primary to how social actors identify with each other and express their identities and how communities organize to build more meaningful and connected spaces. This idea runs through the articles in the issue, exploring the many ways people use digital media, under varied conditions, to negotiate differential mobilities and become placemakers – practices that may expose or amplify preexisting inequities, exclusions, or erasures in the ways that certain populations experience digital media in place and placemaking.

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