Primary Equipment Research Articles

Modern approaches to strength design substantiation for critical elements of WWER NPP reactor internals

This study presents the theoretical and applied results on the development and application of refined models and methods for solving actual problems of mechanics related to the substantiation of strength and forecasting the service life of elements of the primary circuit equipment of WWER nuclear power plants (NPPs). The scientific and applied developments take into account current trends in global practice and contain new conceptual approaches to solving nonlinear boundary value problems in the mechanics of deformed structures. Refined mathematical models have been proposed and theoretically substantiated to describe non-isothermal inelastic deformation processes, taking into account the deformation history of thermal and power loading, radiation effects of hardening, swelling and creep of irradiated metal, and accumulated damage of brittle-ductile fracture. The obtained scientific results are the basis for the methodology of refined design strength analysis and residual life assessment of critical elements of the equipment of the first circuit of WWER reactor units to solve urgent problems of ensuring the conditions for safe operation of Ukrainian NPPs and justifying the terms of their service life extension

Research and Application of Panoramic Data Visualization Platform for Stability Control Equipment Based on the Whole Life Cycle

In recent years, with the mass access of new energy such as UHV commissioning projects and photovoltaic wind, the problems in safely and stably operating regional power grid are becoming more and more prominent. Mass power grid stability control system and equipment play a significant role in this aspect. However, there are a great variety of manufacturers and models of the stability control systems and equipment, as well as configuration schemes for the operation strategy and fixed value of the primary equipment. Due to insufficient technological support, it is relatively inconvenient to manage the information and data of stability and control system on the whole process from feasibility research, initial test, factory debugging, site debugging, commissioning acceptance, protection verification, daily operation and maintenance management to the decommission of the system, thus failing to achieve the objective of classified management according to the relevant requirements, nor to modify and improve in time. Based on the management requirements and status quo of the stability and control equipment, a technical research on the panoramic data visualization platform for the stability control equipment with full life-cycle information covering the feasibility research, release, debugging, commissioning, verification, operation, decommission and so on of the equipment, which is available for the panoramic informationized and digital management of the stability control equipment, so as to realize the whole life cycle and systematic closed-loop management of the stability control system and the equipment.

Experimental study of the heat transfer during the ice formation of TiO2 water-nanofluid around a helical coil CTES system

Attending to the increasing energy consumption, the interest in Cooling Thermal Energy Storage (CTES) has grown since its application might enhance the performance of refrigeration systems by storing thermal energy at low temperatures via ice-making. CTES is essential in many applications, including central air conditioning in buildings, high-powered electronic cooling applications, waste heat recovery, and food processing, to correct the imbalance in electrical power between daytime demand and nighttime abundance. Regarding air conditioning, CTES releases cool energy through ice melting to support the primary chilling equipment throughout the day, regarded as the peak period. Following this path, this work contributes to the existing bench-scale results in the literature by performing a comparative analysis of the thermal performance of CTES systems operating with water and a 0.19 vol.% TiO2 water-based nanofluid as phase change material (PCM). The bench scale CTES system is an insulated rectangular-shaped tank filled with 36 liters of PCM flooding a helical coil. Since a water/alcohol mixture was the coolant, the temperature of the helical coil allowed ice to grow around itself. The CTES with 0.19 vol.% TiO2 nanofluid results in an 11.1% larger amount of ice and a faster charging process (10.6%). Moreover, the heat transfer process observed on the CTES system operating with the nanofluid has improved the system’s maximum energy storage rate by 17.18%. Analyzing the heat transfer process by computing the involved thermal resistances has allowed explaining the observed improvements. Based on this thermal analysis, we have identified that TiO2 nanoparticles mainly affect the natural convection between the ice layer and the liquid phase of the PCM by increasing the convective heat transfer coefficient.

Модернизация оборудования первичной подготовки нефти

The role of the Russian energy industry in modern conditions is indicated. An important part of the energy sector of the Russian Federation is the fuel and energy complex, which is based on oil production. Oil in its pure form contains many impurities (water, sand, gas, pieces of rock, etc.). In order to meet the standards, oil needs to go through many refining processes. Heat exchangers play an important role at the stage of oil refining. It has been found that in the course of work scale, various deposits, pollution are formed in the heat-exchange equipment. Due to these formations, the heat exchanger loses its heating properties. It is possible to prevent the formation of deposits by using ultrasonic method. Structurally, the ultrasonic unit is a pulse generator with two magnetic transducers. When sonicating an oil-water emulsion with ultrasound, destruction occurs, splitting the crystals of hardness salts formed in the heated emulsion. Ultrasonic treatment, propagating over the surface, prevents the formation of scale deposits on it. Ultrasonic treatment is the most effective method for controlling the rheological properties of heavy high-viscosity oils from both technological and environmental and economic points of view. The results of the analysis of the ultrasonic method are presented, its advantages and disadvantages are listed. Conclusions are drawn about the insufficient number of studies comparing ultrasonic and thermal treatment of oil and the need for further study of the application of the ultrasonic method for primary oil treatment equipment.

Fretting Fatigue Life Prediction of Dovetail Structure Based on Plastic Effect and Sensitivity Analysis of Influencing Factors.

Micro relative sliding exists on the contact surface of the main primary equipment's surface structures, resulting in serious fretting fatigue. The plastic effect causes serious fatigue to the structure under alternating loads. Existing fatigue life prediction models fail to fully consider the shortcomings of fretting and plastic effects, which causes the prediction results to be significantly different to real-lifeworld in engineering situations. Therefore, it is urgent to establish a fretting damage fatigue life prediction model of contact structures which considers plastic effects. In this study, a plastic fretting fatigue life prediction model was established according to the standard structural contact theory. The location of dangerous points was evaluated according to a finite element simulation. The cyclic load maximum stress value was compared with the fretting fatigue test data to confirm the error value, and the error between the proposed fretting fatigue life model and the test value was within 15%. Concurrently, we combined this with mass data analysis and research, as it is known that the contact zone parameters have an impact on fretting fatigue and affect the structural lifespan. With the help of ABAQUS, the fretting numerical calculation of the dovetail tenon model was carried out to analyze the sensitive factors affecting the fretting fatigue life of the dovetail tenon structure. By keeping the fretting load unchanged, the contact area parameters such as contact surface form, contact area width and friction coefficient were changed in order to calculate the fretting stress value, σfretting and the dovetail structure was improved to extend its fretting fatigue life. Finally, it was concluded that fretting fatigue was most sensitive to the width and contact form of the contact area. In actual engineering design, multiple factors should be considered comprehensively to determine a more accurate and suitable width and form of the contact area. For the selection of friction coefficient, on the premise of saving costs and meeting the structural strength requirements, the friction coefficient should be as small as possible, and the problem can also be solved through lubrication during processing.

Research on a Field Prompt Device for Substation Switch Remote Control Based on Station Control Layer Switch

The switch in the substation is operated by remote control. To prevent the on-site personnel from being injured by the explosion of the fault switch, a prompt signal shall be sent to the on-site personnel to remind them to stay away from the operating equipment before the remote operation of the primary equipment is required from the perspective of safety. At present, the method of telephone notification or no notification is adopted, which is low in efficiency and poor in operability, and it is difficult to timely and effectively notify on-site personnel. The on-site prompt device for remote switch operation can send prompt signals to on-site personnel before remote switch operation without increasing any workload by monitoring the message of the station control layer switch, which can prevent personal injury and death caused by the explosion of remote switch operation and is of great significance to safety production.

Construction technology of graph and model mutual capacity in smart substation

In order to meet the requirements of automatic mapping of the smart substation models, based on the application requirements of the smart substation model construction and automatic model association configuration, the automatic generation technology of smart station diagram models is studied, and the automatic correlation modeling method and wiring diagram generation technology of primary and secondary equipment models based on the automatic matching of predefined correlation models are proposed. Support the realization of the goal of effective configuration and efficient application of the secondary system model of the smart substation.

Linear Prediction of High-Slip Sinkage for Planetary Rovers’ Lugged-Wheels Based on Superposition Principle

Planetary rovers with lugged-wheels are the primary equipment for Mars exploration, and as exploration missions become more complex, rovers are expected move into more challenging terrains. When moving over soft sand or slopes, lugged-wheels experience high slip and heavy sinkage, and an explicit sinkage prediction model for lugged-wheels is not available. This limits the motion control of planetary rovers. Here, we show that wheel sinkage can be divided into static sinkage, rolling sinkage, shearing sinkage, and digging sinkage, based on motion decomposition. Static sinkage is in accordance with the modified Archimedes' theorem, shearing sinkage is proportional to the slip ratio, and digging sinkage is proportional to rim displacement. Furthermore, the superposition principle of sinkage has been proved, and the various types of sinkage were superimposed to obtain an explicit prediction model without terramechanics parameters for lugged-wheels. The single-wheel test proves that the linear model can predict sinkage for slip conditions from 0 to 0.9 with a prediction accuracy of over 90%. The decomposition and modeling of the sub-sinkage further explores the intrinsic of the lugged-wheels’ sinkage, and the linear prediction model provides a theoretical basis for high slip control of rovers.

CALCULATION OF FAST FRONT OVERVOLTAGES IN VICINITY OF A POWER TRANSFORMER

During their lifespan all the primary equipment installed in power system is subjected to transients. Therefore, it is necessary to adequately dimension and protect the equipment. However, in the networks with high share of renewables, power electronics, cables or near GIS, the failure can occur even though good practice of insulation coordination are fulfilled.
 In this paper high frequency power transformer model is presented. Such model is based on measurements of admittance matrix and is adequate for simulation of fast front transient in EMTP like software. Additionally, simulations of lightning and switching overvoltages are given for the observed power transformer unit.

Online Calibration Study of Non-Contact Current Sensors for Three-Phase Four-Wire Power Cables

Three-phase four-wire power cables are a primary kind of power transmission method in low-voltage distribution networks. This paper addresses the problem that calibration currents are not easily electrified during the transporting of three-phase four-wire power cable measurements, and proposes a method for obtaining the magnetic field strength distribution in the tangential direction around the cable, finally enabling online self-calibration. The simulation and experimental results show that this method can self-calibrate the sensor arrays and reconstruct the phase current waveforms in three-phase four-wire power cables without calibration currents, and this method is not affected by disturbances such as wire diameter, current amplitudes, and high-frequency harmonics. This study reduces the time and equipment costs required to calibrate the sensing module compared to related studies using calibration currents. This research offers the possibility of fusing sensing modules directly with running primary equipment, and the development of hand-held measurement devices.

Mini Review on Energy Storage System

Electric energy and other energy sources will be combined using energy storage systems as the primary equipment. The use of renewable energy sources has increased demand for high-efficiency energy storage technology globally (EST). As a result, a variety of energy storage technologies will be essential to the integration of renewable energy sources (RES) in the current electrical power system. This paper provides a brief overview of several EST that enhance the network's efficiency, reliability, and energy storage density.

РАЗРАБОТКА МОДЕЛИ СИСТЕМЫ РЗА ЦИФРОВОЙ ПОДСТАНЦИИ 110/10 КВ С ПРИМЕНЕНИЕМ ПО SIMULINK

The RPA system of а modem substation is a complex multi-level system with many functions performed. This is especially true for digital substations, where, depending on the architecture of the RPA system, since all control is carried out exclusively in digital format. In this regard, tools are needed to simulate certain algorithms of the RPA system operating on the primary equipment of the substation. There are very few programs that implement these functions, especially considering the fact that most of them do not allow you to change the algorithm of operation of the simulated RPA device, but only have access to changing the settings. Taking into account these factors, within the framework of this work, a model has been developed for the joint operation of primary substation equipment and RPA devices similar to those used in digital substations.

Initial observations of medically complex young adults transitioning to adult care: Revealing data regarding mental health, nutrition, and transition preparedness

BackgroundApproximately one million adolescents with medical complexity transition into adult healthcare each year. Pediatric and adult providers alike have identified several barriers to transition, including insufficient knowledge of community resources, a lack of reimbursement for providing transition services, and an overall shortage of medical providers. Because of these barriers, the healthcare needs and challenges of this population have been understudied. The purpose of this article is to describe findings regarding nutrition, mental health, transition readiness, and caregiver burnout in a patient population of medically complex young adults in the interdisciplinary STEP clinic in the state of Alabama. Through the establishment of streamlined transition programs such as STEP, providers can address the unique health care needs of this patient population, with particular emphasis on optimizing mental health and nutrition. MethodsAll patients seen at the STEP clinic from September 2020 to August 2021 (n = 169) were evaluated through pertinent validated assessments of transition readiness (TRAQ), and/or caregiver burden (ZBI), and/or mental health (PHQ9, GAD7). Additional variables collected from patient charts include age, race, diagnosis, primary insurance type, equipment dependence, and body mass index (BMI). ResultsThe average TRAQ score of patients included in this study is 3.57 ± 1.11. A TRAQ score of below 4.0 suggests that the patient is not yet ready to transition from pediatric to adult care. The average ZBI score of caregivers is 20.97 ± 12.59, which indicates mild to moderate caregiver burden. 33% of patients were found to have moderate to severe anxiety, and 28% were found to have moderate to severe depression. Only 3.6% of patients seen at the STEP clinic have a BMI within normal limits. 113 of our patients have ongoing use of medical technology, and 49% are wheelchair users. ConclusionsThe need for organized transition care for medically complex young adults is apparent and growing. This patient population faces unique challenges in navigating the adult healthcare system, and patients are often unprepared for the transition. It is crucial that multidisciplinary clinics in which mental health and nutrition are addressed become accessible to all patients within this high-risk population.

Categorization and evaluation of voltage sag control methods and equipment: A study

Voltage sags have emerged as major problems in power quality in the recent years and the categorization of methods and tools available for reducing voltage sag is becoming increasingly crucial. Modern approaches and tools for minimizing voltage sag are based on an extensive research, aimed at developing effective categorization techniques to assist end users in selecting the most suitable tools and settings. To begin, this research provides a comprehensive assessment of the existing voltage sag control methods and equipment. Furthermore, it presents a classification scheme that divides voltage sag control strategies into three groups: those implemented by the power provider, the customer, and the equipment manufacturer. A classification system for voltage sag control equipment based on the number and type of power supply, taking into account the variations between single and dual power supply voltage sag control devices is also proposed. Additionally, to assist consumers in selecting the optimal device, this research demonstrates how primary voltage sag control equipment utilizes the preventive measures and an integrated software.

A Data-Driven Intelligent Energy Efficiency Management System for Ships

Shipping carries most of the cargo in international trade, with the fuel cost of ships is the major expense. Much attention has been paid to saving fuel in ship operation. First, to save fuel, an intelligent energy efficiency management system is developed to collect data related to ship energy efficiency. The main engine is the primary fuel-consuming equipment on a ship. It is important to carry out a comprehensive evaluation on the energy efficiency of the main engine. To achieve this goal, an ensemble machine learning approach combining the physics-based empirical model is used to perform a regression analysis on two different indicators. The indicators include the engine shaft power and fuel consumption rate per unit time. Second, the influence of the input features on energy efficiency indicators is analyzed, and some conclusions are drawn. On this basis, a novel trim optimization method based on piecewise regression is suggested, which is helpful to reduce ship resistance. In conclusion, this system can help ship operators to judge whether the main engine and ship are in good working condition and take appropriate measures to save energy for ships.

Ensuring fire safety in the technosphere: Important aspects

This article discusses the factors that lead to fires, how to prevent and avoid them and the different types of primary fire extinguishing equipment used in production. It also describes the algorithm of actions to be followed by personnel and the public in case of fire, according to the fire safety instructions. Despite the fact that the fire safety rules and fire pyramid conditions (source of fire, temperature, combustible substance and oxygen access) are widely known, the number of technogenic fires in Russia is still high. In connection with this, the article examines the fires that have occurred with loss of life and material damage. These cases are analyzed with the aim of developing and modernizing rules of behavior aimed at preventing fires, as well as developing an algorithm of action in extreme situations and forecasting possible fires. The article presents statistical data on fires in the Russian Federation. Measures are also suggested to evaluate the risk taking into account the layout and design of buildings, prevent fires and determine fire hazards. After analyzing the situations, preventive measures and fire safety propaganda are recommended, as well as regular training and education of personnel, workers and rescuers in order to reduce the number of fires and thus minimize material and human losses.

Decontamination applications in primary circuit equipment of nuclear power plants

Due to the reactions taking place in the reactor, radioactive contamination occurs on and/or near the surfaces of the equipment used in nuclear power plants. Contamination is a radioactive pollution in the solid phase, which may exist in solution or be carried as a gas/vapor. It can be caused by a very small amount of radioactive material, and since every known element has at least one radioactive isotope, there are more than a hundred elements that can cause contamination. Removing of this contamination by physical and chemical methods is defined as decontamination. The main purpose of decontamination is reducing the activity level of contaminated equipment which may occur during operation or after decommissioning of nuclear power plants. By decontamination process, the radioactive contamination formed on the surfaces or in the depths close to the surface of the equipment is removed by chemical and physical methods. Within the scope of this study, decontamination applications in the literature were explained; regulatory perspective and legislative infrastructure issues for Turkey were discussed. Within the scope of this study, the decontamination applications in the literature were explained, the regulations of the Regulatory Bodies in other countries for decontamination were examined, and in this direction, the regulatory perspective for Turkey and the suggestions for the legislative infrastructure were discussed.

Development and Experimental Research of VFTO Measuring Sensor

Very fast transient overvoltage (VFTO) generated by an operating disconnector is one of the main reasons for electromagnetic disturbance in gas-insulated switchgear (GIS) substations. Generally, the amplitude of VFTO can be used as one of the references for the insulation design of GIS primary electric power equipment, so it is necessary to obtain its accurate amplitude. In this study, a new VFTO measuring sensor is developed and its measurement performance is demonstrated through hundreds of operations by a disconnector in a 220 kV GIS test circuit. The validation shows that the low cut-off frequency of the new VFTO measuring sensor has been greatly expanded to 0.01 mHz, which is improved by about 50% compared with the old sensor. The measurement accuracy of amplitude of VFTO micro-pulse improves greatly by about 80% compared with the old one. Thus, the new VFTO measuring sensor can fully meet the measurement needs of trapped charge voltage, power frequency voltage, and high-frequency transient voltage in VFTO waveform. It can be used to provide more accurate data support for insulation design of GIS primary power electric equipment in extra-high voltage (EHV) and ultra-high voltage (UHV) GIS substations.

Discrimination method of low-current grounding fault of primary and secondary integrated equipment under three-phase asymmetric harmonic power flow calculation

In order to realize the accurate judgment of the ground fault and improve the fault discrimination effect, this paper proposes a low-current ground fault discrimination method for the primary and secondary fusion complete sets of equipment under the calculation of three-phase asymmetric harmonic power flow. The three-phase asymmetric harmonic power flow calculation is carried out, the ground fault line selection model is constructed according to the calculation results, and the faulted line is obtained by the zero-sequence active component method and the zero-sequence reactive power component method; the wavelet packet transform method is used to extract the transient zero-sequence power direction, and use it as a line selection criterion to identify whether a ground fault occurs. The amplitude characteristic enhancement value of each section is obtained by calculation. According to the distribution characteristics of the zero-sequence current amplitude of the faulted feeder, the corresponding section is selected as the fault section, and the mutation logic array is used in the determined fault section to realize the low-current grounding fault judgment. The experimental results show that the method has high judgment accuracy in practical application, and the highest value is 98.5 %, which indicates that the method can accurately judge the fault line and determine whether ground fault occurs.

An integrated anti-interference suppression strategy based on L-type and π type circuit series for integrated distribution box

With the wide application of intelligent distribution equipment, the operation and management level of the distribution network has been significantly improved. At present, domestic and foreign scholars' researches on the primary and secondary integration technology of distribution switch are still in its infancy. And it needs to be further discussed. Based on the structure theory of the distribution terminal acquisition unit, this paper analyzes the influence of temperature rise, pressure, and strong electromagnetic interference on the performance of primary and secondary fusion equipment under field operating conditions. To improve the operation reliability of the integrated equipment, an anti-interference suppression measure of the primary and secondary fusion distribution switch is proposed based on the series connection of L-type and π-type circuits and the accuracy detection method of the transformer. It solves the problem of high-frequency damping oscillation effectively at the input of the transformer under the condition of electromagnetic interference. This paper verifies the feasibility and effectiveness of the integrated fusion technology of the primary and secondary fusion equipment of distribution switches through theory and experiment.