Power System Engineers Research Articles

Using a heat pump at the complex of energy generation and compressed air production for mining companies

A further efficiency upgrading of thermal power plants and boiler units at mining companies is linked to increasing the initial parameters of steam. Modern power units can work with an efficiency of 55-58%. However, it is possible to make a review of additional possibilities of heat utilization at a thermal power station. It is quite possible to increase the efficiency by 2-3% more due to the heat regeneration both in this cycle and in the water treatment units. A technology has been developed that combines the ORC and the cycle of compressed air production in a single power engineering system using an improved thermal-transformer, specifically, a refrigeration-heating machine what works in thermal networks of a thermal power station. In addition, from a practical point of view, it is shown that the efficiency of thermal power plant can be improved in comparison with standard schemes. Use of heat pumps beyond heating systems of private houses is becoming increasingly common in centralized heating systems and with feed water of thermal power plants. It significantly reduces the cost of heat and electricity production. Besides, solar collectors can integrate very well into the technological scheme of heating network water at the thermal power plant.

Opportunities for Embedded High-Voltage Direct Current: Evaluating the Benefits for the Legacy ac Grid

Power system engineers and planners often consider high-voltage dc (HVdc) systems for bulk power transmission over long distances. There are two technologies within HVdc: line-commutated converters (LCC-HVdc) and voltage-source converters (VSC-HVdc). Each type has its own suitable range of applications. LCC-HVdc is a mature technology that has been available since the 1970s and uses thyristor valves. LCC-HVdc is commonly applied for high-capacity power transmission between two strong power systems (high short circuit ratio) over long distances with limited dynamic requirements (e.g., features such as fast power reversal, dynamic reactive power support, or black start are not available or are available only with limited performance). Currently installed systems reach ratings of 12 GW at a transmission voltage of ?1,100 kV and may cover distances beyond 3,000 km. The introduction of VSC-HVdc in the late 1990s initiated the use of self-commutated valves employing insulated-gate bipolar transistors with a significant improvement in dynamic performance. Presently, the ratings of VSC-HVdc a relower than those of LCC-HVdc. VSC-HVdc systems are now installed with a rating of 3,000 MW at a transmission voltage of ±525 kV, and higher ratings are under development. For special applications such as the connection of offshore wind power plants or connection to/between weak grids, VSC-HVdc often offers the only technoeconomically viable solution.

Stability Assessment of Stochastic Differential-Algebraic Systems via Lyapunov Exponents with an Application to Power Systems

In this paper, we discuss stochastic differential-algebraic equations (SDAEs) and the asymptotic stability assessment for such systems via Lyapunov exponents (LEs). We focus on index-1 SDAEs and their reformulation as ordinary stochastic differential equations (SDEs). Via ergodic theory, it is then feasible to analyze the LEs via the random dynamical system generated by the underlying SDEs. Once the existence of well-defined LEs is guaranteed, we proceed to the use of numerical simulation techniques to determine the LEs numerically. Discrete and continuous QR decomposition-based numerical methods are implemented to compute the fundamental solution matrix and use it in the computation of the LEs. Important computational features of both methods are illustrated via numerical tests. Finally, the methods are applied to two applications from power systems engineering, including the single-machine infinite-bus (SMIB) power system model.

Perspectives for Mitigation of CO2 Emission due to Development of Electromobility in Several Countries

The creep trend method is used for the analysis of the development of electric car production in three regions: The United States, the European Union and Japan. Based on vehicle registration and population growth data for each year the creep trend method using historical data for the years 2007–2017 is applied for forecasting development up to 2030. Moreover, the original method for calculating the primary energy factor (PEF) was applied to the analysis of power engineering systems in the regions investigated. The assessment of the effects of electromobility development on air quality has been performed, reduction values for pollutant and greenhouse gas emissions have been determined, which was the main objective of this manuscript. Mitigation of air pollutant emissions, i.e., carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxides (NOx) was estimated and compared to the eventual expected increase of emissions from power plants due to an increase of the demand for electricity. It can be concluded that electricity powered cars along with appropriate choices of energetic resources as well as electricity distribution management will play the important role to achieve the sustainable energy economy. Based on the emission reduction projections resulting from the projected increase in the number of electric cars, (corrected) emissions will be avoided in 2030 in the amount of over 14,908,000 thousand tonnes CO2 in European Union, 3,786,000 thousand tonnes CO2 in United States and 111,683 thousand tonnes CO2 in Japan.

Power Quality Improvement of Distribution Network Using BESS and Capacitor Bank

The power demand around the world is increasing rapidly. The aging distribution network architectures are used by the existing utility companies to deliver power to the consumers, which significantly affects the reliability, stability and quality of the delivered power. Different techniques such as compensation devices have been used by power system engineers and researchers to maintain the quality of power transmitted to end users. In this paper, wattage and volt-amp reactive (VAR) planning scheme has been proposed by using the combination of battery energy storage systems (BESS) and compensators to deal with the vulnerability of networks to voltage drop and system inefficiency. The cost-effective combination of BESS and shunt capacitor bank will then be analyzed to indicate the benefit of the proposed scheme.

Разработка автономных энерготехнологических комплексов с водородным накопителем энергии

Разработка автономных энерготехнологических комплексов с водородным накопителем энергии

SF6 Alternatifi Yalıtkan Gazların Çevresel ve Fizyokimyasal Özellikleri

Research on alternative dielectric gases to eliminate the disadvantages of SF6, which is widely used in GIS and switching systems in the power system engineering, has been an important study topic in the literature for nearly 40 years. Because of environmental priorities defined by international agreements such as the Kyoto Protocol and Doha Amendment, the restrictions on the use of SF6 make these studies an obligation. Although the number of alternative dielectric gases studied for this purpose is quite high, these gases can be classified under the titles of non-synthetics, hydrocarbons (HCs), fluorocarbons (FCs), hydrofluorocarbons (HFCs), fluoronitriles (FNs), fluoroketones (FKs) and other synthetic gases. In this study, the gases classified under these titles are compared using the dielectric constant relative to SF6, Global Warming Potential (GWP), atmospheric lifetime, boiling point and toxicity parameters used in the comparison of dielectric gases. When compared with these parameters, non-synthetic air, CO2, and N2, C3F7CN from FNs, and C5F10O and C6F12O from FKs stand out among alternative gases to SF6. These alternatives are used in some innovative power system industry applications and have a widespread use potential in the insulating gas industry instead of SF6.

Nipping Blackouts in the Bud: Introducing a Novel Cascading Failure Network

Cascading blackouts are the oldest major unsolved technical problem in power system engineering, highly visible since the Northeast Blackout of 1965 in North America. In this article, we review some cascading blackouts and past work on the problem. New metrics measure network stress to identify and reduce the risk of cascading failures.

A New Approach for PV Nodes Using an Efficient Backward/Forward Sweep Power Flow Technique

Most of the distribution networks may contain reactive power sources such as distributed generators with reactive support, static VARs compensators or even switching capacitors. In this sense, it is necessary to have an appropriate and convenient model for controlled-voltage (PV) nodes to be applied in power flow distribution networks. On the other hand, the conventional power flow analysis has been an important tool for all power systems engineers. The nonlinear methods based on the Newton- Raphson method and its decoupled forms and the Gauss-Seidel with Ybus factorized method have been popular to nowadays. However, these methods have presented some convergence problems when are applied to distribution networks analysis. The reasons are the inherent characteristics of distribution networks, such as high r/x ratios, very low branch impedances, radial feeder configurations, among others. In this sense, the techniques based on Backward/Forward Sweep (BFS) methods for power flows have been widely applied in distribution systems. However, as above mentioned for controlled-voltage (PV) nodes some challenges in BFS power flow algorithms are presented, some authors have proposed hybrid methods, iterative methods, sensitivities matrix- based methods, among others. Unfortunately, those methods usually require complex formulations and long execution times. In this paper a new approach and easily controlled-voltage (PV) formulation joint with a simple power flows methodology, called LRSV method, is presented. The results show that this no-complex methodology permits to obtain better execution times, responses in a better way for different load, generation and configurations and some tests cases to demonstrate the effectiveness of the proposed methodology.

Efficient Energy of Smart Grid Education Models for Modern Electric Power System Engineering in Iraq

Smart grid integrates the use of high end technologies so that the generation of energy as well as its delivery can be done with greater performance to the multiple locations and regions. As Iraq is one of the elevating countries in the energy sector and enormous projects, the need to integrate the smart grids arise. This manuscript underlines the assorted perspectives of the smart grid technologies with the integration of solar system and the implementation aspects in Iraq. With the integration of smart grid based architecture and cumulative formulation of the effectual approaches the overall energy can be optimized and higher degree of throughput can be achieved with greater values in the overall performance. In Iraq, there are many projects which are under development and many development using which the overall energy based projects are getting successful in Iraq with the overall elevated growth of the country in multiple sectors including power, security, corporate, international relations, finance and many others. In this research manuscript, the assorted factors and the projects with the multiple dimensions of energy optimization and power saving in Iraq are presented with the pragmatic results.

Improving Power Flow Control in AC Transmission System Using Phase Shifting Transformer (PST)

Obtaining optimal power flow has been a challenge over the years for power system engineers. Several ways and technologies ranging from conventional to the use of modern Flexible Alternating Current Transmission Systems (FACTS) devices have been incorporated into the power system to ensure optimal flow of power. FACTS devices used are capable of mitigating several power system problems ranging from line overloading, voltage instability, transient instability, and Power system congestion and so on. Phase shifting transformer (PST) is a FACTS device that is capable of controlling power flow problems in a network by varying its phase angle. PST, when installed at appropriate locations on the power system is capable of redirecting and redistributing power flow from overloaded lines to the less loaded ones, hence ensuring an optimal performance and improved performance of the power system.This paper evaluates the effect of incorporating the PST on the IEEE 5 bus system. Newton-Raphson load flow technique is employed in modeling the IEEE 5 bus system and the PST. Simulation was carried out using MATLAB software package for both the steady state condition and with the incorporation of PST. Results showed that overloading on some transmission lines was checked and mitigated by redistribution of active power across the system. There was also reduction of losses on the lines. Keywords: Phase Shifting Transformer, Power System, Power flow, MATLAB, Newton-Raphson. DOI: 10.7176/CEIS/11-4-03 Publication date: June 30 th 2020

Power Systems Protection Course in the Electrical Engineering Programs Offered in Brazil

This paper presents a study of the Power Systems Protection (PSP) course in the Electrical Engineering programs offered in Brazil. The course offered to the undergraduate students has great importance for the future professional of Power System Engineering and should consider aspects to ensure that the future professionals have the necessary skills to carry out the craft of the profession. Initially, the importance of the PSP theme is presented through a compilation of local data (Brazil) regarding the Brazilian Interconnected Electrical System and its impacts on the operation and issues as failures and accidents. The article continues briefly describing the Electrical Engineering programs in Brazil, with current and historical data on Engineering and specifically Electrical Engineering, comparing them with other programs. The official number of Electrical Engineering programs of public and private educational institutions in Brazil and the number of programs that the course is mandatory or optional is also compared. Following, it is presented the characteristics and common subjects addressed in the course syllabus in the different best Brazilian educational institutions according to the Brazilian Institute of Studies and Research (INEP). Finally, the paper is concluded presenting a discussion about the necessity of maintain, increase or decrease the offer of this particular course and the necessity of update its syllabus.

Assessment of optimal allocation of renewable distributed generator sources in distribution network

AbstractThe integration of distributed generators (DGs) into distribution networks in optimal allocation is one of the main issues facing power system engineers to ensure improved stability and economic operation. This article presents a detailed analysis of the impacts of the optimal allocation and the number of DGs on both system steady‐state and transient performances of distribution networks. An oscillatory particle swarm optimization (OPSO) algorithm was used to find the optimal allocations of DGs via minimizing various objective functions that deal with Total Transmission Losses, Voltage Regulation, and Power Performance Index. The OPSO is used to optimize these functions as a single and as a multiobjective optimization problem. The effectiveness of the method is demonstrated with the IEEE‐14 bus as an example of distribution networks with a 50% increase in system loading. Two penetration scenarios have been considered, the optimal sizes and locations of DGs are obtained, and the results are presented. In addition, the impact of the penetration level of Photovoltaic and Wind Energy sources on transient performance is obtained using detailed nonlinear models of both synchronous machines and DGs sources. The system response is then obtained when the system is subjected to a three‐phase short circuit fault for six cycles and the results are presented in a comparative form for different penetration levels. The techniques and results presented in the article form a useful base for power system engineers in planning and operating distribution systems with high penetration levels of RDG sources.

Criteria for Assessing the Severity of Short-Circuit Faults for Choosing Controlling Actions of Emergency Automation

Abstract—The transient stability of power engineering systems depends on the severity of short-circuit (SC) faults, generator load in the prefault mode, and postemergency conditions. This paper considers the criteria for assessing the severity of SC faults for choosing controlling actions to prevent violations in transient stability and proposes the most representative parameters for automatically ranking various kinds of SC by severity.

Combinatorial Optimization of AC Optimal Power Flow With Discrete Demands in Radial Networks

The ac optimal power flow (OPF) problem is one of the most fundamental problems in power systems engineering. For the past few decades, researchers have been relying on unproven heuristics to tackle OPF. The hardness of OPF stems from two issues: 1) nonconvexity and 2) combinatorial constraints (e.g., discrete power extraction constraints). The recent advances in providing sufficient conditions on the exactness of convex relaxation of OPF can address the issue of nonconvexity. To complete the understanding of OPF, this article presents a polynomial-time approximation algorithm to solve the convex-relaxed OPF with discrete demands as combinatorial constraints, which has a provably small parameterized approximation ratio (also known as polynomial-time approximation scheme (PTAS) algorithm). Together with the sufficient conditions on the exactness of the convex relaxation, we provide an efficient approximation algorithm to solve OPF with discrete demands, when the underlying network is radial with a fixed size and one feeder. The running time of the PTAS is O(n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4m</sup> / <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϵ</sup> T), where T is the time required to solve a convex relaxation of the problem, and m and ϵ are fixed constants. Based on prior hardness results of OPF, our PTAS is among the best achievable in theory. Simulations show that our algorithm can produce close-to-optimal solutions in practice.

Advanced techniques of power system restoration and practical applications in transmission grids

Optimal restoration of a real-time power system following a disruption is a complex process. In view of that and with increase in frequency and severity of power system outages across the US and their impact on consumers and utilities, North American Electric Reliability Corporation elevated the standard of compliance for power system restoration. While several utilities have proposed solutions addressing the elevated standards based on dynamic programming, they could not address the issues for large-scale power systems and real-time operations including those using steady-state and transient analysis due to the curses of dimensionality. In this paper, we introduce a restoration process based on approximate dynamic programming integrated with solution space reduction methodology. The main theoretical foundations of the methodology and key algorithms used in this restoration process include the knowledge of power system engineering, complex network science, concepts of graph theory, and dynamic programming in operation research. We first use the proposed method to demonstrate an optimal restoration process on the IEEE 118-bus test system and then on a 2000-bus synthetic test system. This method addresses the concerns related to the curses of dimensionality and simplifies the solution space and thus can be applied to various complex real-time operation settings.

Review on Oscillatory Stability in Power Grids With Renewable Energy Sources: Monitoring, Analysis, and Control Using Synchrophasor Technology

Oscillatory stability has received immense attention in recent years due to the significant increase in power electronic converter (PEC)-interfaced renewable energy sources. Synchrophasor technology offers superior capability to measure and monitor power systems in real time, and power system operators require better understanding of how it can be used to effectively analyze and control oscillations. This article reviews state-of-the-art oscillatory stability monitoring, analysis, and control techniques reported in the published literature based on synchrophasor technology. An updated classification is presented for power system oscillations with a special emphasis on oscillations induced from PEC-interfaced renewable energy generation. Oscillatory stability analysis techniques based on synchrophasor technology are well established in power system engineering, but further research is required to effectively utilize synchrophasor-based oscillatory stability monitoring, analysis, and control techniques to characterize and mitigate PEC-induced oscillations. In particular, emerging big data analytics techniques could be used on synchrophasor data streams to develop oscillatory stability monitoring, analysis, and damping techniques.

Preface

The first Annual Advanced Technology, Applied Science, and Engineering Conference, ATASEC 2019, was doing in Batu, East Java, Indonesia between 29 and 30th August 2019, with the participation of 116 participants. This conference was organized by State Polytechnic of Malang, Indonesia. The conference theme was “Sustainable Development through Science, Technology and Vocational Engineering Education”. ATASEC 2019 addressed emerging challenges and innovations in the industry 4.0 era in the field of applied science, technology, engineering, and vocational engineering education.ATASEC 2019 aims to provide a platform for academicians, researchers, students and practitioners to promote and to share ideas and knowledge and to create international networks for sustainable development of science and technology in the future. The scope of the conference covered 12 scope, which is Electrical Power Systems Engineering, Electronics and Microelectronics Engineering, Information Systems Technology, Telecommunication Engineering, Mechanical Engineering, Mechatronics and Robotics Technologies, Computer Science and Engineering, Chemical Engineering, Civil Engineering, Industrial and Manufacturing Engineering, Environmental Science and Engineering, Education, Vocational Engineering and Technology.Three keynote speakers of the ATASEC 2019 conference was:1. Prof. Kohei Arai. Professor of Saga University, Japan Adjunct Professor of Arizona Univ, USA.2. Dr. M.A. Burhanuddin. Associate Professor of Universiti Teknikal Malaysia Melaka, Malaysia.3. Dr. Luchis Rubianto. Vice Director of Cooperation Affairs, State Polytechnic of Malang, Indonesia.The organizing committee would like to express appreciation to all sponsors, and participants for great contribution to the success of this conference.The EditorsDr. Ade Gafar AbdullahIndrazno Siradjuddin, Ph.D.Erfan Rohadi, Ph.D.LIST OF COMMITTEE, CONFERENCE PHOTOGRAPH are available in this pdf.

Honorary Member in 2013, Jun HASEGAWA; Development of Power System Engineering and Internationalization of Academic Activities

1．はじめに

Power System Oscillation Mode Prediction Based on the Lasso Method

This paper utilizes modern statistical and machine learning methodology to predict the oscillation mode of interest in complex power engineering systems. The damping ratio of the electromechanical oscillation mode is formulated as a function of the power of the generators and loads as well as bus voltage magnitudes in the entire power system. The celebrated Lasso algorithm is implemented to solve this high-dimension modeling problem. By the nature of the L 1 design, the Lasso algorithm can automatically render a sparse solution, and by eliminating redundant features, it provides desirable prediction power. The resultant model processes a simple structure, and it is easily interpretable. The precision of our sparse modeling framework is demonstrated in the context of an IEEE 50-Generator 145-Bus power network and an online learning framework for the power system oscillation mode prediction is also provided.