Electric Power Engineering Research Articles

Optimal Control of Active Power of Two Micro-grids Interconnected with Two AC Tie-Lines

Active power balance and frequency control are important tasks in the daily management of a power system. With the integration of several microgrids in the modern power system, the balancing of sources of energy has become a major concern for electrical power engineers and researchers worldwide. New power systems require more flexibility in optimization and control design to ensure their ability to maintain the balance between generation and load of the system. The present paper discusses an optimal control design for minimization of the power flow in tie-lines and frequency deviations in the microgrid, which will lead to power balance between the generation and load demand of the system. The system being studied consists of two microgrids, each made up of a wind farm, conventional power system (large hydro or thermal plant), photovoltaic system, battery energy storage system and the system load. Optimal control theory is applied to control the power flow between two microgrids. The Matlab environment is used for simulations.

A flipped mode teaching approach for large and advanced electrical engineering courses

ABSTRACTA fully flipped mode teaching approach is challenging for students in advanced engineering courses, because of demanding pre-class preparation load, due to the complex and analytical nature of the topics. When this is applied to large classes, it brings an additional complexity in terms of promoting the intended active learning. This paper presents a novel selective flipped mode teaching approach designed for large and advanced courses that has two aspects: (i) it provides selective flipping of a few topics, while delivering others in traditional face-to-face teaching, to provide an effective trade-off between the two approaches according to the demands of individual topics and (ii) it introduces technology-enabled live in-class quizzes to obtain instant feedback and facilitate collaborative problem-solving exercises. The proposed approach was implemented for a large fourth year course in electrical power engineering over three successive years and the criteria for selecting between the flipped mode teaching and traditional teaching modes are outlined. Results confirmed that the proposed approach improved both students’ academic achievements and their engagement in the course, without overloading them during the teaching period.

Electric Power Engineering Cost Predicting Model Based on the PCA-GA-BP

In this paper a hybrid prediction algorithm: PCA-GA-BP model is proposed. PCA algorithm is established to reduce the correlation between indicators of original data and decrease difficulty of BP neural network in complex dimensional calculation. The BP neural network is established to estimate the cost of power transmission project. The results show that PCA-GA-BP algorithm can improve result of prediction of electric power engineering cost.

Publicly accessible online power quality monitoring databases

While performing power system studies, it can be difficult to find real-world data to supplement and/or reinforce experimental data. This study provides information on how four databases can be obtained through a new online power quality (PQ) monitoring system accessible via the Internet and how the data in these databases can be used. The available data includes National Oceanic and Atmospheric Administration Space Weather, National Renewable Energy Laboratory Wind, the Department of Energy (DOE)/Electric Power Research Institute Disturbance Library, and the PQSoft PQ Waveform Library. The cloud-based databases are available at no cost to educational institutions worldwide for the purpose of training electric power engineering students.

CIRCUIT-DESIGN SOLUTIONS AND INFORMATION SUPPORT OF CITY ELECTRIC NETWORKS IN THE CONDITIONS OF THE SMART GRID

The structure, circuit-design solutions and information support of the city electric networks in the conditions of the SMART GRID have been analyzed. It is demonstrated that the new conditions of functioning of electric power engineering, increasing demands for its technological state and reliability in most countries determined the transition to a restructuring of electrical networks to be based on the SMART GRID (intelligent power networks) innovative new structure. The definitions of the SMART GRID, its various attributes and characteristics in most developed countries including Belarus are presented. It is revealed that the existing and future circuit and constructive solutions that can automate the process of managing modes of urban electric networks under the SMART GRID conditions are manifold. At present, the most common in distribution networks are the sources of distributed generation (combustion turbines, wind turbines, photovoltaic installations, mini-hydro, etc.). The patterns and problems of information traceability of a traditional urban networks of the unified energy system of Belarus have been analyzed, and it is demonstrated that in the conditions of the SMART GRID most of the problems of the control mode that are characteristic for traditional distribution networks 6–10 kV and 0.38 kV, lose their relevance. Therefore, the present article presents and features the main directions of development of automatic control modes of the SMART GRID.

Safety analyses of reactor VVER 1000

Department of Electrical Power Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology (BUT) is participating in research of safety analyses of nuclear power plants, especially nuclear power plants with VVER 1000 reactors. Main task of this research is lattice calculation, homogenized cross section processing for further 3D nodal reactor core simulation and coupled reactor core simulations and thermal-hydraulic calculations. Verification of deterministic methods and obtained results is provided by Monte Carlo simulation. Taking in account several years of experience with calculation tools provided by United States Nuclear Regulatory Commission (U.S. NRC), the complex simulation is performed by simulations tools such as nuclear package SCALE, reactor core simulator PARCS and thermal-hydraulics code TRACE.

Development of technical skills in Electrical Power Engineering students: A case study of Power Electronics as a Key Course

Technical skills are one of the attributes, an engineering student must attain by the time of graduation, as per recommended by Engineering Accreditation Council (EAC). This paper describes the development of technical skills, Programme Outcome (PO) number 5, in students taking the Bachelor of Electrical Power Engineering (BEPE) programme in Universiti Tenaga Nasional (UNITEN). Seven courses are identified to address the technical skills development. The course outcomes (CO) of the courses are designed to instill the relevant technical skills with suitable laboratory activities. Formative and summative assessments are carried out to gauge students’ acquisition of the skills. Finally, to measure the attainment of the technical skills, key course concept is used. The concept has been implemented since 2013, focusing on improvement of the programme instead of the cohort. From the PO attainment analysis method, three different levels of PO attainment can be calculated: from the programme level, down to the course and student levels. In this paper, the attainment of the courses mapped to PO5 is measured. It is shown that Power Electronics course, which is the key course for PO5, has a strong attainment at above 90%. PO5 of other six courses are also achieved. As a conclusion, by embracing outcome-based education (OBE), the BEPE programme has a sound method to develop technical psychomotor skills in the degree students.

Power-functional network.

Power grids and their properties have been studied broadly in many aspects. In this paper, we propose a novel concept, power-flow-based power grid, as a typical power-functional network, based on the calculation of power flow distribution from power electrical engineering. We compare it with structural networks based on the shortest path length and effective networks based on the effective electrical distance and study the relationship among these three kinds of networks. We find that they have roughly positive correlations with each other, indicating that in general any close nodes in the topological structure are actually connected in function. However, we do observe some counter-examples that two close nodes in a structural network can have a long distance in a power-functional network, namely, two physically connected nodes can actually be separated in function. In addition, we find that power grids in the structural network tend to be heterogeneous, whereas those in the effective and power-functional networks tend to be homogeneous. These findings are expected to be significant not only for power grids but also for various other complex networks.

An Electric Power Engineering Supervision Mechanism Research Based on Big Data

With the introduction and application of big data, the power companies have entered the era of big data. In this paper, we make a study of electric power engineering supervision mechanism based on big data from four areas of cost, quality, schedule and safety. We have clever integration of the original project supervision approach and power big data, changing the way of doing supervision, by building two databases: Transverse database and longitudinal database, namely: the same project database and historical project database. During the course of project supervision, we collect the real-time data of this project and extract useful information of the database of vertical and horizontal. Then, we compare real-time data with databases to identify problems and take remedial measures timely. The fusion of Big data and power project supervision is becoming a trend, which could achieve it roundly and timely. It is also optimal choice of project supervision by now.

Criterion complex optimization in electric-power systems

A method of criterion programming has been developed for solving optimization problems in electric- power systems. The method is based on the techniques of similarity theory, criterion analysis, and geometrical programming. The main advantages of the criterion-programming method lie in using the criteria of technical and economic similarity and the possibility of solving problems of any degree of difficulty. The objective function and limitations of different types can be presented in any real form without additional transformations. This simplifies the statement of optimization problem and makes it possible to take into account more parameters to be optimized. The method of criterion programming was developed to solve problems of optimal control of electric-power system to improve the reliability and efficiency of its operation. Examples considered in the article show the fundamental interdependence between technical and economic parameters characterizing the state of electric-power systems and make it possible to reveal the main technical and economic regularities of complex electric-power systems. The possibilities of the criterion-programming method that are presented in the article expand the range of problems that can be solved by technical, economic, and mathematical analysis in electric-power engineering and can be used in other fields of science.

Design and development of a smart grid laboratory for an energy and power engineering technology program

This paper presents the design and development of a laboratory facility to accompany a three-course power systems sequence in the Energy and Power Engineering Technology program at Purdue University. This hardware-based system is modeled after the US electric grid and emulates a complete power network: generation, transmission and distribution, end-use, and control. The approach taken is to divide the lab hardware in two: a simplified three-phase, three-bus system for power transfer from a synchronous generator and infinite bus to a variable load, and a multi-bus single phase system with prime movers and associated generators, transformers, contactors, transmission lines, constant impedance loads, induction motor loads, power factor correction capacitors, DC generation, AC/DC conversion, energy storage, high voltage DC transmission, and supervisory control and data acquisition. The bifurcation of the lab hardware by phase enables the hands on teaching of both three-phase power basics and more advanced content in context of the power grid, supporting a systems-based approach to electric power engineering education.

Energy System Flexibility: The Importance of Being Nimble [From the Editor

Our energy system flexibility is cusses creative ways that the power can reliably accommodate the lar le development of variable resoure and load that fluctuates considerably weather, price, and behind the-meter generation. This issue's guest editors, Mark O'Malley and Benjamin Kroposki, collected six articles that discuss the importance of flexibility and how it can be achieved in ways not always considered by electric power engineers.

Establishment of Visual Supervision Mechanism for on - site Supervision of Electric Power Engineering

The quality of power engineering is an important guarantee for the power supply. The existing engineering supervision mainly relies on manual completion and lacks effective supervision mechanism. From the perspective of power engineering site supervision, the function and significance of visualization supervision mechanism are introduced, the application of visualization of power industry is enumerated, the necessary elements of visualization supervision of power engineering is summed up, and the visual supervision mechanism establishing for power engineering is discussed. The establishment of visualization regulatory mechanisms has a role in upgrading for power engineering site supervision and quality control.

Issues of Latvian Energy Supply Security: Evaluation of Criminal Offences in Latvia’s Electricity Market

IntroductionThere are a lot of factors that influence the efficiency of efforts preventing criminal offences of an economic nature; these factors include networking of stakeholders (e.g., Akhmadeev and Manakhov, 2015; Ala-Juusela et al., 2014; Aleksejeva, 2016; Barberis et al., 2014; Branten and Purju, 2015; Cirjevskis, 2015; Cuneo et al., 2014; Fuschi and Tvaronaviciene, 2016) and level of development of country (e.g., Corneliu, Tamosiuniene, 2015; Balitskiy et al., 2014; Balkyte and Tvaronaviciene, 2010; Dudzeviciute et al., 2014; Lapinskiene et al., 2013; Lapinskiene et al., 2014; Bialowqs, 2015; Pires Manso et al., 2015; Balitskiy et al., 2016). The list of factors could continue much further, but suffice it to summarize that they are often categorized into soft, or indirect, factors, and hard factors, together encompassing all mechanisms of enforcement, from legislation to punishment of crimes. Taking into account the complexity of the phenomenon itself, we want to delineate the context of our research.The energy security of a country involves a number of different facets, such as energy availability, efficiency, and afordability (Cherp and Jewell, 2014; Dezellus et al., 2015; Lisin et al., 2015; Espona, 2016); level of techology novelty and its vulnerability (Grubicka and Matuska, 2015; Prause, 2016); public sector performance (Bileisis, 2014; Borshchevska, 2015; Caurkubule, Rubanovskis, 2014; Garskaite-Milvydiene, 2014; Lauzikas et al., 2015); and available means to enhance social security (Bileviciene and Bileviciute, 2015; Bistrova et al., 2014; Dzemyda and Raudeliuniene, 2014; Tvaronaviciene et al., 2015). In addition to these, behavioral patterns also undeniably affect a country's energy security.To determine the significance of criminal offences in electric power engineering services in Latvia and to evaluate the efficiency of solutions therefor, the authors of this research developed a questionnaire targeting specialists from various sectors in Latvia: law enforcement institutions (police and prosecutor's office) and employees of energy companies (JSC Latvenergo, JSC Sadales tikls). These specialists represent the population of the empirical research. The questionnaire was conducted electronically (http://aptaujas.du.lv/index.php/813329/lang-lv), and the responses served as the data for this empirical research.Research hypotheses were formulated taking into account various factors that influence criminal offence in electric power engineering services: fraud icentives (Girunas and Mackevicius, 2014; Giriuniene, 2013; Isoraite, 2013; Lace et al., 2015; Lauzikas and Mokseckiene, 2013); technology (Gerlitz, 2016; Guruz and Scherer, 2014; Ignatavicius et al., 2015; Jefremov and Rubanovskis, 2015; Iganatavicius et al., 2015; Grubicka and Matuska, 2015; Rezk et al., 2015; Prause, 2016); perceptions of energy security (Miskinis et al., 2013; Mânsson et al., 2014; Raudeliuniene et al., 2014; Leonavicius et al., 2015; Narula and Reddy, 2015; Njaramba et al., 2015; Oganisjana and Surikova, 2015); and risk awareness (Ruza et al., 2016). Authors put particular emphasis on enforcement efficiency. Therefore, the following hypotheses were formulated:* Protection of electric energy market through criminal law is important and topical both for energy supply companies and police officers.* There is a necessity for legislative framework modernization in order to prevent criminal offences in the electric energy market.* An appropriate provision of police resources is necessary to prevent criminal offences in the electric energy market and to ensure effective protection of the said market.* There are differences in the evaluation of the efficiency of various groups of measures used to resolve criminal offences in the electric energy market.* There is interdependence between the evaluation of the problem of illegal usage of electric energy and the effective application of various groups of measures to solve the problem. …

Problems of standardizing and technical regulation in the electric power industry

A mandatory condition to ensure normal operation of a power system and efficiency in the sector is standardization and legal regulation of technological activities of electric power engineering entities and consumers. Compared to the times of USSR, the present-time technical guidance documents are not mandatory to follow in most cases, being of an advisory nature due to the lack of new ones. During the last five years, the industry has been showing a deterioration of the situation in terms of ensuring reliability and engineering controllability as a result of the dominant impact of short-term market stimuli and the differences in basic technological policies. In absence of clear requirements regarding the engineering aspects of such activities, production operation does not contribute to the preserving of technical integrity of the Russian power system, which leads to the loss of performance capability and controllability and causes disturbances in the power supply to consumers. The result of this problem is a high rate of accident incidence. The dynamics of accidents by the type of equipment is given, indicating a persisting trend of growth in the number of accidents, which are of a systematic nature. Several problematic aspects of engineering activities of electric power engineering entities, requiring standardization and legal regulation are pointed out: in the domestic power system, a large number of power electrotechnical and generating equipment operate along with systems of regulation, which do not comply with the principles and technical rules representing a framework where the Energy System of Russia is built and functioning one of the reasons of accidents is the absence of mandatory requirements for putting in operation and (or) managing the operation of electric power facilities, their equipment, and devices the absence of standardization and regulation of relations between the owners of technologically connected power facilities when creating (modernizing) the relay protection, emergency control, and regime-based automated systems or other systems of engineering control in an energy system the lack of mechanisms to implement an orchestrated policy in the sector due to the absence of common rules and standards.

Application of Geographic Information System to Power Distribution System Analysis

This paper presents a new application of Geographic Information System (GIS) in the field of electric power engineering. GIS can analyze and visualize information related to Geography. Recently photovoltaic (PV) generation is introduced in the power system day by day for the needs of clean energy. If it is installed in large quantities, voltage variation occurs with a risk of worsening electric power quality. In this context the limit of introducing PV in the power system should be correctly grasped. This research focuses on distribution system with large amount of PV. In order to grasp the limit of introducing PV in the distribution system, PV generation should be evaluated correctly and analyze the state of the distribution system. Although PV generation is proportional to solar radiation, the amount of solar radiation is affected by the shadow of the building, the angle, and the direction. Therefore, it is difficult to grasp solar radiation falling on the PV panels accurately and calculate PV generation. GIS can solve the problem. GIS can model actual townscape and analyze the amount of solar radiation. By executing solar radiation analysis to the modeled townscape, the amount of solar radiation on any places in the town can be evaluated. Using the result of the analysis, PV generation installed on any places in the town can be estimated and more proper distribution system analysis can be performed than conventional analysis.

Investigation of Natural Draft Cooling Tower in China

ABSTRACTThe natural draft cooling tower has been widely used in thermal power plants because of its stable operation, lower maintenance cost, and smaller environmental impact. Hundreds of natural draft cooling towers have been built in China, including different types and various capacities of conventional cooling towers, seawater cooling towers, flue gas injection cooling towers, cooling towers with water collecting device, dry cooling towers, and others. A wide range of investigation for natural draft cooling towers was carried out for the first time by the Electric Power Planning & Engineering Institute in 2013 in China. Based on the collected data and summarized information, the statistical results and conclusive opinions are analyzed. The development trend of natural draft cooling tower technology is also explored in this paper. The investigation results are expected to be a reference for designing and operating natural draft cooling towers in thermal power plants.

AN ANTHOLOGY OF THE DISTINGUISHED ACHIEVEMENTS IN SCIENCE AND TECHNIQUE. PART 33: ELECTROMAGNETIC COMPATIBILITY AND PROTECTION FROM ACTION OF POWERFUL ELECTROMAGNETIC INTERFERENCE OF RADIOELECTRONIC, ELECTRICAL ENGINEERING AND ELECTRIC POWER EQUIPMENT

Purpose. Implementation of brief analytical review of basic scientific and technical achievements in area of electromagnetic compatibility (EMC) and protection from destabilizing and striking action of powerful electromagnetic interference (PEMI) of natural and artificial origin of radioelectronic, electrical engineering and electric power equipment. Methodology. Scientific methods of collection, analysis and analytical treatment of scientific and technical information in a sphere EMC and such areas of knowledge’s as radioelectronics, electrical engineering and electric power engineering. Results. A brief scientific and technical review is resulted modern positions problems EMC and protection of equipment from action on them PEMI. It is shown that PEMI can result in failures in-process and death of examined equipment. Annual harm in the industrially developed countries of the world from the striking affecting of PEMI modern equipment with integral microcircuits and semiconductor devices can make ten of milliards of USD. The basic methods of protection of equipment are resulted from PEMI and protective devices (PD), intended for the increase of effectiveness of modern equipment to the action of external PEMI. Principles of work of the resulted PD and their basic technical descriptions are described. Originality. On the basis of materials of scientific monographs, journal publications, normative documents and internet-reports systematization of basic PD, in-use presently in an area EMC and protection of different equipment from the hazard agency of external PEMI is executed. Practical value. Popularization of scientific and technical knowledge’s in an area EMC and protection of modern equipment from a dangerous action on them PEMI. Formulation of important for society scientific and technical problems and tasks, arising up in an area EMC and providing of the reliable functioning of modern equipment in power electromagnetic interference.

THE STUDY OF APPLIED METHODS OF THE COMPLEX FUNCTION THEORY AS A MEANS OF FORMATION OF MATHEMATICAL COMPETENCE OF FUTURE ENGINEERS

В контексте современной парадигмы высшего профессионального образования, ключевую роль в подготовке инженеров играет практикоориентированность содержания образования. Это означает, в частности, что содержание дисциплин основной образовательной программы должно обеспечивать выпускника вуза не столько набором знаний в соответствующей предметной области, сколько возможностью их применения для решения профессиональных задач. С позиций этого подхода качество математической подготовки будущего профессионала характеризуется его математической компетентностью. Цель работы: обоснование целесообразности изучения прикладных методов теории функций комплексного переменного в качестве средства формирования математической компетентности инженеров по направлению 13.03.02 Электроэнергетика и электротехника. Она вытекает из противоречия между значительной ролью математических дисциплин в подготовке будущих инженеров и недостаточным уровнем их математической подготовленности.

Comparative analysis of cooling systems for energy equipment of combined heat and power plants and nuclear power plants

In the 20th century, the thermal power engineering in this country was oriented toward oncethrough cooling systems. More than 50% of the CHPP and NPP capacities with once-through cooling systems put into operation before the 1990s were large-scale water consumers but with minimum irretrievable water consumption. In 1995, the Water Code of the Russian Federation was adopted in which restrictions on application of once-through cooling systems for newly designed combined heat and power plants (CHPPs) were introduced for the first time. A ban on application of once-through systems was imposed by the current Water Code of the Russian Federation (Federal law no. 74-FZ, Art. 60 Cl. 4) not only for new CHPPs but also for those to be modified. Clause 4 of Article 60 of the Water Code of the Russian Federation contravenes law no. 7-FZ “On Protection of the Environment” that has priority significance, since the water environment is only part of the natural environment and those articles of the Water Code of the Russian Federation that are related directly to electric power engineering, viz., Articles 46 and 62. In recent decades, the search for means to increase revenue charges and the economic pressure on the thermal power industry caused introduction by law of charges for use of water by cooling systems irrespective of the latter’s impact on the water quality of the source, the environment, the economic efficiency of the power production, and the living conditions of the people. The long-range annual increase in the water use charges forces the power generating companies to switch transfer once-through service water supply installations to recirculating water supply systems and once-through–recirculating systems with multiple reuse of warm water, which drastically reduces the technical, economic, and ecological characteristic of the power plant operation and also results in increasing power rates for the population. This work comprehensively substantiates the demands of power engineering specialists that the ban on development and construction of once-through service water supply systems should be lifted and the proposals for new parameters, e.g., temperature and back pressure, for designing low-potential equipment of steam-gas and steam-power plants.