Research on Intelligent Monitoring and Maintenance Technology of Substation Based on Digital Twin

The design, research and development, test, operation and maintenance of power grid substation equipment are relatively independent. Related problems in each link cannot be comprehensively managed from the perspective of the full life cycle of equipment. Operation and maintenance personnel need to face data monitoring, network monitoring, equipment monitoring, business system monitoring, fault diagnosis and repair and other business scenarios. There are many types of information, complex association relationship, abstract and inefficient operation and maintenance information, “man-machine-object” can not be two-way cooperation and interaction, fault diagnosis and troubleshooting difficulties. Digital substation intelligent monitoring operational digital twin applications, digital intelligent substation operations provide operational monitoring service ability, realize the grid digital substation twin modeling and environment reconstruction, false or true merged superposition, two-way coordinated interaction, twin intelligence operations and panoramic visual monitoring, field devices for power grid operation maintenance, resource scheduling, and construction planning to provide guidance, Fully guarantee the safe and reliable operation of power grid equipment, realize the full life cycle management of power grid equipment, and improve the level of intelligence, visualization and digitalization of power grid.

A review paper on memory fault models and test algorithms

Testing embedded memories in a chip can be very challenging due to their high-density nature and manufactured using very deep submicron (VDSM) technologies. In this review paper, functional fault models which may exist in the memory are described, in terms of their definition and detection requirement. Several memory testing algorithms that are used in memory built-in self-test (BIST) are discussed, in terms of test operation sequences, fault detection ability, and also test complexity. From the studies, it shows that tests with 22 N of complexity such as March SS and March AB are needed to detect all static unlinked or simple faults within the memory cells. The N in the algorithm complexity refers to Nx*Ny*Nz whereby Nx represents the number of rows, Ny represents the number of columns and Nz represents the number of banks. This paper also looks into optimization and further improvement that can be achieved on existing March test algorithms to increase the fault coverage or to reduce the test complexity.

An IoT Based Intelligent Traffic Management System and Its Implementation on Cupcarbon for Smart Cities

This paper proposes an internet of things (IoT) based intelligent traffic management system that can aid problematic traffic situations in smart cities by classifying congestions via sensory data, and then controlling traffic lights and creating alternate routes for incoming vehicles to the congested zones in order to relieve or avoid congestions completely. The proposed intelligent traffic management system consists of different subsystems such as Test Operation, Supervisory, Traffic Light, and Pathfinder subsystems. The system is represented by flowcharts with their explanations and its operation with some defined scenarios is validated with the CupCarbon simulation environment.

Preventing Scan-Based Side-Channel Attacks by Scan Obfuscating with a Configurable Shift Register

Scan test is widely used in integrated circuit test. However, the excellent observability and controllability provided by the scan test gives attackers an opportunity to obtain sensitive information by using scan design to threaten circuit security. Hence, the primary motivation of this paper is to improve the existing DFT technique, i.e., to enhance the chip security on the premise of guaranteeing test quality. In this paper, we propose a new scan design method against scan-based side-channel attack. In the proposed method, the encryption structure is adopted, which requires the correct test authorization code to carry out normal test operation. Without the correct test authorization, the attackers cannot obtain the desired scan data, preventing the scan-based side-channel attacks. Furthermore, the test authorization code is determined by the nonvolatile memory built into the chip to realize the inconsistency of the test authorization code for each chip.

Study vibration of worm gear boxes

The article describes the method of experimental analysis of transmission mechanisms. The test station enables to test different types of gears and to simulate their different operating conditions close to reality. The tests may be short-term and long-term. The course and results of the test operation of the screw reducer are described. Measured and evaluated were low-frequency and high-frequency vibration, temperature and wear functional parts of the teeth.

Aging Characteristics of Contact Electrodes of Low Voltage DC Switches

With the present state of the direct current (DC) distribution market, securing the safety of the DC distribution system is emerging as a major issue. Like AC distribution systems, DC switches and circuit breakers are one of the main means to ensure safety. However, in the DC system, since there is no current zero point in the load current, the phenomenon occurring when the circuit is cut off is different from that of the AC system, so technical research is required to cope with this. In this study, the aging characteristics of the contact electrode of a 400 V class low voltage DC (LVDC) switch is studied for the development of wall-mount switches or circuit breakers for residential houses. As an arc extinguishing method to break DC load current, a prototype experimental circuit breaker that uses a magnetic extinguishing method that is effective for blocking low voltage low power DC is invented, and an automated experiment system is established. The DC switch test repeats the operation of turning it on and off 13,000 times, and continuously evaluates the performance of the electric contacts by calculating the voltage drop between the electrode contacts and the corresponding Ohmic resistance value when conducting every 500 times. This paper tests six contact materials to compare the aging characteristics of them by evaluating contact resistance during the test period. AW18-Cu composite material showed the most stable and excellent contact performance for LVDC switches during the entire test operation period.

Development and characterization of a mobile γ spectrometer and its field deployment for in situ radioactivity measurements

A mobile γ–ray spectrometer (AMESOS) has been developed using a 3”×3” NaI(Tl) detector, a custom–made mounting holder, and portable electronics to perform in situ measurements of radioactivity. The spectrometer was calibrated using standard point sources and its absolute efficiency was determined. As a field test operation, AMESOS was deployed on the premises of the University of Athens Zografou campus focusing on estimating the NORM levels. Data were analyzed and used to create radiological maps for the metropolitan UoA campus for the first time. Besides natural radioactivity levels, trace concentrations of 137Cs were also detected, attributed to the Chernobyl fallout in Greece. An overall steady performance of the spectrometer was observed throughout the field operation. AMESOS is ready to be deployed for in situ studies of environmental radioactivity and radwaste management.

Technological Peculiarities of Manufacturing Two-Media UAV Using Fused Deposition Modeling

В статье представлены двухсредные дроны разработанные в различных странах мира. Приведены ссылки на источники. Представлена конструкция разработанного в ФГБОУ ВО «КнАГТУ» двухсредного дрона. Разработанный аппарат является конвертопланом. Описана примененная для изготовления двухсредного дрона технология с применением метода послойного наплавления филамента. Описаны выявленные в процессе изготовления и пробной эксплуатации недостатки использованной технологии изготовления дрона и выбранного филамента PLA. Проведен анализ филаментов с целью подбора вида пригодного для изготовления объектов контактирующих с водой по физико-механическим и химическим характеристикам. Подобраны тесты для определения физико-химических характеристик филамента. Рекомендован для изготовления двухсредных дронов пластики PETG и HIPS. Приведен разработанный тест для оценки герметичности напечатанных на 3d принтере деталей. Приведен разработанный тест для отработки параметров печати на 3d принтере. Приведены рекомендованные для печати параметры слайсера. Описана разработанная технология изготовления на 3d принтере компонентов беспилотных дронов. The paper describes two-media UAV developed in various countries. Source references are given. The paper presents a design of a two-media UAV developed in Federal State Budgetary Educational Institution of Higher Education Komsomolsk-na-Amure State University. The developed device is a convertiplane. Fused deposition modeling technology used for manufacturing a two-media UAV is described. The paper shows the downsides of UAV manufacturing technology and selected PLA filament identified during manufacture and test operation. Filaments have been analysed to identify a type suitable in its physical, mechanical and chemical characteristics for manufacturing objects in contact with water. Tests to determine physical and chemical characteristics of the filament have been selected. PETG and HIPS plastics are recommended for manufacturing two-media UAV. The paper describes a test developed to evaluate hermetic sealing of parts manufactured with 3D printer. A test developed to refine 3D printer parameters is given. Slicer parameters recommended for printing are given. A technology developed for manufacturing UAV components with 3D printer is described.

Simulation And Development Of Electronic Ballast for High Pressure Discharge Lamps

The advantages and disadvantages of using electromagnetic ballasts for power supply of high pressuredischarge lamps (HPDL) are considered. The advantages of using electronic ballasts for supplying HPDL are shown. The analysis is fulfilled of the operation of the HPDL when powered by a high-frequency current, in particular, high-pressure sodium lamps (HPSL). It is indicated that when high-pressure discharge lamps are supplied with a high-frequency current, acoustic resonance may appear. The basic requirements to be met by electronic ballasts for HPSL have been determined. The topology of construction of electronic ballasts for supplying HPDL with a capacity of up to 1 kW has been selected. It has been established that half-bridge converters with inductive ballast and active power factor corrector (PFC) allow maintaining a stable power on the lamp while changing its parameters and efficiency. Mathematical modelling of the electronic ballast based on a half-bridge converter and an ignition device for the sodium discharge lamps DNaT type has been carried out. According to the proposed topology, the electronic ballast was developed for a DNaT 600 lamp powered from the 380 V network. Test operation of the lamps confirmed the reliability of the proposed electronic ballast topology.