BI‐DIRECTIONAL CHARGER CIRCUIT AND ITS APPLICATIONS

Purpose The use of power sectionalizers in electric power distribution networks as disconnecting devices for optimum network configuration is indispensable. Major reasons to use sectionalizers, here manual sectionalizers, is their lower installation and operating prices compared to other types of disconnecting devices and that most of conventional realistic electric power distribution systems are still using manual sectionalizers due to their ease of procurement. However, in case of failure for these switches, power supply interruptions are unavoidable unless optimum solutions are used for configuration (and possibly reconfiguration) of sectionalizers. Thus, in this research, binary exchange market algorithm (BEMA) as a novel evolutionary metaheuristic is used to meet the maximized customer satisfaction by optimized configuration of sectionalizers within electric power distribution networks in the presence of distributed generations (DGs). To solve the problem, BEMA is used on sectionalizing switch placement problem, which has only two open and close (0/1) states. A novel multi-objective optimization problem has been formulated as a function of two aspects, namely, improved reliability index (for customer benefit) and minimized sectionalizing switch costs (for utility benefits). Simulations are carried out in three different case studies to validate the effectiveness of the BEMA both in theory and practice: Standard IEEE 33-bus test system, practical feeder-8 of MeshkinShahr Town’s electric power distribution network in northwest of Iran; and Roy Billinton test system Bus 4 (RBTS-Bus 4). The obtained results are compared with those of the previously validated ant colony optimization (ACO) technique in RBTS-Bus 4. Design/methodology/approach The optimum configuration of sectionalizers in the presence of DGs has been formulated as a multi-objective function consisting of two conflicting objectives. First objective is to improve the power distribution network reliability indices. Second objective is to fulfill the first objective with a minimized sectionalizing switch cost. The latter is probably obtained by reducing the number of installed sectionalizers. The obtained results by BEMA have been compared with those of ACO technique. Findings In this paper, optimal configuration of sectionalizers has been performed based on a multiobjective function by binary exchange market algorithm. By simulations carried out on two standards and one practical test systems, the proposed algorithm effectiveness was confirmed and the obtained results were compared to ACO algorithm. Changing weighting factors shows that better satisfaction can be obtained when difference between the weighting factors is relatively greater. In other words, the reliability membership function is more than switch cost membership, and thus, if the values of two weighting factors are close enough, the satisfaction level reduces. The number of installed sectionalizing switches by BEMA and ACO techniques in different scenarios were performed. Originality/value Proposal of a novel multi-objective function for finding optimal location of sectionalizers in the presence of DGs with binary exchange market algorithm whose merit over the other heuristics is to consider all the problem specifications only in one multi-objective function. Despite previously reported works that have used various high-priced protective devices for achieving the enhanced reliability this research only utilizes inexpensive manual sectionalizers with the least possible cost in the presence of DGs. Two standard test cases IEEE 33-bus test system and RBTS-Bus 4 and one realistic test case feeder-8 of MeshkinShahr Town power distribution network in northwest of Iran are used to demonstrate the effectiveness of the proposed technique in theory and real-world applications. Thus, utilities may take the advantage of the proposed method for configuration of sectionalizers in their own local power distribution systems throughout the country.

Design of an advanced electric power distribution systems using seeker optimization algorithm

In the new designs of military aircraft and unmanned aircraft there is a clear trend towards increasing demand of electrical power. This fact is mainly due to the replacement of mechanical, pneumatic and hydraulic equipments by partially or completely electrical systems. Generally, use of electrical power onboard is continuously increasing within the areas of communications, surveillance and general systems, such as: radar, cooling, landing gear or actuators systems. To cope with this growing demand for electric power, new levels of voltage (270 V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DC</inf> ), architectures and power electronics devices are being applied to the onboard electrical power distribution systems. The purpose of this paper is to present and describe the technological project HV270DC. In this project, one Electrical Power Distribution System (EPDS), applicable to the more electric aircrafts, has been developed. This system has been integrated by EADS in order to study the benefits and possible problems or risks that affect this kind of power distribution systems, in comparison with conventional distribution systems.

Achieving the right balance between centralized and distributed energy resources (DERs) is key in increasing sustainability, resiliency and energy security. As DERs continue to proliferate, more complete models will be required to study the dynamic interactions between the electric power transmission and distribution systems. To address this need, results from a study are presented concerning the new supporting role of large, fossil-based generators in a power system with an increased level of renewable energy (distributed in particular). This work considers the transmission and distribution system interplay and it contributes to the establishment of fair and transparent operational and regulatory criteria to ensure sustainability and resiliency in power grids with increased levels of renewable energy penetration.

With an average herd size of 113 mature cows, Cayuga County is home to 280 dairy farms and 31,500 dairy milking cows producing approximately 855 million gallons of milk per year. The Cayuga Dairy industry is a major contributor to the countys economy, employing nearly 1200 people, while generating $140,000,000 of revenue from sale of milk alone. At the same time, the Cayuga County dairy industry also produces 5.7 million gallons of manure daily: (a) Nearly 34% of this manure is produced on smaller farms. (b) Digesters are expensive pieces of equipment and require attention and care. ( c) The on-farm digester systems have fairly long payback (>10 years) even for larger CAFO farms (>1000 milking cows). In 2005, Cayuga County Soil and Water Conservation District (The District), a Public Agency under Cayuga County, decided to undertake a centralized community digester project. The primary goal of the project was to develop an economically sustainable model, under the auspices of The District to address manure management issues facing the smaller dairies, improve the water quality and improve the quality of life for Cayuga County residents. It is believed that the District has accomplished this goal by completing construction of Cayuga County Regional Digester on a parcel of land behind the Cayuga County Natural Resource Center located at 7413 County House Road in the Town of Sennett in Cayuga County, New York. The digester facility consists of the following major components. 1. Transfer Station: This an indoor truck bay, where 35,000 gallons of manure from three local farms, 8,500 gallons of liquid organic food-processor waste, and 1,200 gallons of brown grease are unloaded from tanker trucks and the digested slurry is loaded onto the tanker trucks for delivery back to the participating farms. 2. Anaerobic Digester: The project utilizes a hydraulic mix anaerobic digester, a unique design that has no internal moving parts for mixing. The digester, which operates at mesophilic temperatures, is designed to process the daily feedstock and produce 220,000 SCF2 of biogas per day. The digester also produces 44,000 gallons of digested slurry per day. 3. Biogas Conditioning System: The plant employs a biological biogas conditioning system to remove the H2S and moisture contents of the biogas and prepare it to be used by the plant generation system. 4. Combined Heat and Power System (CHP): This is a 633kW high efficiency biogas-fired GE-Jenbacher model JMS-312 GS-NL reciprocating engine cogeneration system. The heat recovery system incorporated into the package is designed to capture the waste heat from the engine exhaust, the jacket cooling water and the engine oil circuit. 5. Electrical Substation and Power Distribution Systems: An electrical distribution system has been constructed on-site that aggregates the electrical service of the different county buildings on the District campus into a county owned electric distribution system that is interconnected with the CHP and the local electric grid. The electrical system is designed, in accordance with the utility guidelines, to allow grid-parallel operation of CHP and provide for import and export of electric power. 6. Thermal Energy Distribution System: The heat recovery system has been integrated into a high temperature water distribution system that distributes the heat to the thermal circuits for the anaerobic digester facility. Additional piping has also been installed to transfer the remaining thermal energy to other county buildings on the campus. On a daily basis, the plant will co-process 35,000 gallons of manure from local dairy farms, 8,500 gallons of food-processor waste and 1,200 gallons of brown grease to produce 200,000 ft3/d of biogas and 44,000 gallons of pathogen-free nutrient-rich digested slurry for agricultural use by farms and in the local area.The biogas fueled CHP produces 5,157,000 kWh of electricity and 19,506 dekatherms of thermal energy per year. Electrical power generated by the cogeneration system powers all the buildings on the Cayuga County campus and any surplus power is exported to the grid under a power purchase agreement. Heat recovered from the cogeneration system will be used to maintain the temperature of the process equipment and the excess will be transported to the Cayuga County Public Safety Building to offset purchase of fossil fuel to fuel the boilers. The majority of plant operations are unmanned and automated. However, the plant will have a small staff of well-trained personnel to coordinate the feedstock deliveries and shipments, supervise the day-to-day operation, monitor the systems and perform maintenance, maintain a safe and reliable operation and to respond to emergencies.

Four local error estimators used for a posteriori h-type adaptive finite-element mesh generation are presented and compared in the solution of several steady-state multiconductor eddy-current problems, encountered in electrical power transmission and distribution systems. The proposed technique combines four different criteria with the concept of Delaunay triangulation to provide finite-element triangular meshes, adaptive to the characteristics of each problem. By refining the elements with the largest errors and recomputing the solution iteratively, finite-element meshes having a uniform error density are obtained. The problems examined lead to quantitative results concerning the performance of each estimator in the accuracy of the solution, in terms of both convergence rate and quality of electromagnetic field lines.

In the transmission and distribution systems there are very important activities such as: planning, design, operation, maintenance and commercialization, which are based on the knowledge with good precision of its operation variables: active powers, reactive powers and phasor voltages. Misleading values of these variables distort the mentioned activities and can cause serious technical, economic and social consequences. The measurements of these variables are made in the bars of the lines by a chain of processes, where each of them introduces an error to the measurement. The power measurement errors are usually large, of the order of 3 or 4%. In the measurements of each line, anomalous or absent measurements are detected in many intervals of each month, mainly due to the indicated limitations and temporary failures in the meters. In the present work a method of calculation for the detection, identification and reconstruction of absent and anomalous measurements in the national system of electrical transmission is proposed and developed through the use of state estimation techniques and estimation of parameters based on least squares and the equations of charge flow of the lines, using all the measurements of active energies, reactive energies and existing tensions in the fifteen minute intervals, in both ends of the lines corresponding to the month in which their evaluation is carried out. The application of the proposed method to the 220KV Chimbote -Trujillo line for a sub set of 21 data rows vectors from a total of 2880 data row vectors corresponding to its July 2018 operation is presented.

Spatiotemporal dynamics of in-use copper stocks in the Jing-Jin-Ji urban agglomeration, China

Electric Power Distribution System Learning has demands for learning outcomes so that students understand the concept, and have basic knowledge and skills in various constructions of electric power distribution networks. This requires varied and more contextual learning methods and requires contextual learning media as well. The learning media used should be able to provide real experiences for students in simulating the electric power distribution system according to the concepts they are learning. However, the ability of students in the configuration of various distribution networks has problems because there is no suitable learning media. Therefore, it is necessary to develop a valid power distribution system trainer for use in learning. This study aims to produce a valid electric power distribution system trainer. This type of research is research &amp; development (R&amp;D) using the ADDIE model. Research is limited to the development stage (development). The validation test was carried out by 4 validators using an instrument in the form of a validation sheet. The results of the validation show that the electric power distribution system trainer developed is in the valid category, both for content quality aspects and objectives, instructional, and technical. This indicates that the trainer developed is appropriate for use in learning in order to test its effectiveness.

Distribution transformers are a vital component of electrical power transmission and distribution system. Frequent Monitoring transformers faults before it occurs can help prevent transformer faults which are expensive to repair and result in a loss of energy and services. The present method of the routine manual check of transformer parameters by the electricity board has proven to be less effective. This research aims to develop a low-cost protection system for the distribution transformer making it safer with improved reliability of service to the users. Therefore, this research work investigated transformer fault types and developed a microcontroller-based system for transformer fault detection and protection system using GSM (the Global System of Mobile Communication) technology for fault reporting. The developed prototype system was tested using voltage, current and temperature, which gave a threshold voltage higher than 220 volts to be overvoltage, a load higher than 200 watts to be overload and temperature greater than 39 degrees Celsius to be over temperature was measured. From the results, there was timely detection of transformer faults of the system, the transformer protection circuits were fully functional, and fault reporting was achieved using the GSM device. Overall, 99% accuracy was achieved. The system can thus be recommended for use by the Electricity Distribution Companies to protect distribution transformers for optimal performance, as the developed system makes the transformers more robust, and intelligent. Hence, a real-time distribution transformer fault monitoring and prevention system is achieved and the cost of transformer maintenance is reduced to an extent.

Assuming the availability of a high energy and power density battery of 100 Wh/lb and 100 W/lb by the 1980' s, the energy consumption and efficiency of electric and heat engine cars are compared on an equal basis. This is achieved by considering a reference electric car of 3150-lb weight similar in body construction, aerodynamics, and rolling resistance to a conventional heat engine car of equal weight, and comparing the performance of the two cars over the same driving modes. The reference electric car is then used as a baseline to evaluate the possible improvements in future electric cars. The energy consumption for an optimized 2000-lb electric car of driving range, comfort, and performance comparable to a conventional car is estimated. Assuming a gradual growth in electric car population leading to their widespread use by the 1990's, the impact on electric power generation and distribution systems is estimated. Though the analysis is based on a high energy and power density battery the results may be extrapolated to electric cars using lower performance batteries. It is noted that batteries with lower energy density can provide sufficient driving range to fulfill a significant portion of our transportation needs and their continued development and improvement will accelerate the achievement of the high energy-density goal [1].

Fault identification in electrical power distribution system using combined discrete wavelet transform and fuzzy logic

An integral formulation is derived from the Biot-Savart law in conjunction with Gaussian numerical integral methods and applied to the computation of magnetic fields surrounding a two-wire twisted-pair transmission line in the static case. The results show the effects of the length of the pitch of the twisted-pair line on magnetic fields surrounding these lines and the 3-D nature of this field. It appears that, to obtain uniform heating, one should try different shapes for the exciting coils. Increasing the length of the heating coils improves the uniformity near the center of the workpiece, but has the effect of overheating at the edges. Changing the distance between the coils or the supply frequency does not have a significant effect on the heating pattern. The significance of the analysis lies in its relation to electromagnetic compatibility considerations which must be taken into account in the design of the electric power transmission and distribution system of NASA's Space Station Freedom (SSF). >

Historically, electric power distribution systems were considered passive subsystems served by the larger transmission grid. Recently, smart grid initiatives have driven the evolution of distribution systems into active systems with market-aware customers and distributed power generation. Along with more diverse and complex injections, contemporary distribution systems are equipped with additional sensing equipment, two-way communications networks, and advanced metering infrastructure (AMI). These are essential technologies that enable several core functions of a smart grid, including real-time monitoring and online control. This thesis presents several tools for the online analysis and control of modern electric power distribution systems. "Online" refers to a control framework that can react to changing system conditions in order to maintain static security and meet different operating objectives. Specifically, the objective of this research is to integrate temporal information (i.e., forecasts) into distribution system analysis tools while maintaining fundamental engineering requirements by re-examining classical problems through a contemporary lens. Connected by an underlying injection forecast model, three research topics are explored: 1) distribution load capability, 2) analytical time window selection for quasi-static time series (QSTS) analysis, and 3) distribution state estimation with explicit consideration of non-synchronized measurements. The work proposed here is a necessary step towards distribution system optimization in an online setting with uncertain and/or bidirectional power flows.

In this paper, the authors propose a new concept of electrical power distribution system named flexible, reliable and intelligent and energy conservative distribution system (FRIENDS). In the near future, electrical power systems will be facilitated by dispersed energy resources and dispersed energy storages on the demand side. The electrical power distribution system itself will have to be changed to cope with these facilities. The authors propose a flexible power distribution system for such a situation. Noticeable characteristics for the proposed system (FRIENDS) are flexible network reconfiguration for uninterrupted power supply through power electronics devices, new protective relaying schemes, online information service to customers (including automated metering), DSM and home automation as well as multi-quality power supply. In this paper, the new concept of the power distribution system of FRIENDS is explained, and how the new functions can be realized is discussed.