Repair Of Electrical Equipment Research Articles

LQR controller design for portable power supply based on flyback converter

Abstract The stability of the power repair equipment guarantees the reliability of the repair of electrical equipment. The following problems exist in the power supply of the emergency equipment: the load equipment randomly cuts in the power supply network; load equipment requires fast dynamic performance of the power supply. This challenges the stability of the portable power supply with the Flyback converter as the core. In this paper, an optimal feedback control strategy based on linear quadratic regulator (LQR) theory is proposed to improve the dynamic and steady-state performance of the Flyback converter. First, the state-averaged space model of the Flyback is derived and established. Second, an output voltage feedback integral controller is introduced to eliminate the steady-state error of the output voltage. Next, according to the LQR optimal control theory, the control model of the Flyback converter has been established, and the parameter design of the controller has been carried out by obtaining the optimal feedback gain matrix of the system. Finally, the simulation models are implemented with an output power of 120 W and a switching frequency of 50 kHz. The simulation results prove that the LQR controller provides superior performance than the traditional PI controller.

ФУНКЦИОНАЛЬНЫЕ ВОЗМОЖНОСТИ СИСТЕМ РЕЛЕЙНОЙ ЗАЩИТЫ И АВТОМАТИКИ ЦИФРОВЫХ ПОДСТАНЦИЙ

A comprehensive analysis of the data on the technical accounting of the functioning of electrical relay protection complexes in the unified national electric power grid of Russia is presented, thanks to which the main types, causes and patterns of incorrect and emergency operation of the entire range of protections are established. An approach to the potential transition to servicing industrial electric power facilities based on the use of the entire set of relay protection functionality to solve the problems of automating maintenance procedures on a new hardware and methodological basis is proposed. Optimal criteria for evaluating the operability of electrical relay protection complexes and automation of digital transformer substations are formulated, which additionally take into account the influence of completeness and reliability of electrical information on the condition of protected electrical equipment affecting the quality of protection. It is shown that the organization of maintenance of electrical equipment by means of relay protection and automation according to the actual condition at an energy facility with a developed system of automated information collection and processing is a natural step of transformation in the electric power industry. The analysis of the relevance of the current technology of maintenance and repair of electrical equipment showed a significant reduction in the impact on the functional groups of measurement, information environment and receiving modules of electrical relay protection complexes and automation of digital substations.

Penerapan Partial Credit Model (PCM) Untuk Meningkatkan Kemampuan Berpikir Kritis Siswa Pada Mata Pelajaran Perbaikan Peralatan Listrik Pada Kelas XI Titl Di SMK Negeri 1 Kediri

The learning process carried out by teachers in schools is a very important activity in improving the quality of education. The learning process carried out by the teacher cannot be separated from the use of instruments in the form of questions that will be presented to determine the level of students' critical thinking. The use of the right questions is very important to support the learning process in the future. One of them is a question based on the partial credit model to determine the level of critical thinking of students which is considered suitable to be implemented in the learning process. This study aims to determine the validity and reliability of the partial credit model instrument in the subject of electrical equipment repair and to determine the position of respondents and items on the wright map. The research method used is an experimental method in the form of a One-Shot Case Study. The experimental subjects were students of class XI TITL 2 at SMK Negeri 1 Kediri. Then to analyze and process data using ministep software. The results showed that the partial credit model based question instrument was declared valid for use with the unidimensionality test results obtained by the raw variance explained by measures measurement result of 40.4%, the partial credit model based item instrument was stated to be reliable with the item reliability rating result of 0.93 and 0.94, obtained person reliability values of 0.68 and 0.70, and obtained values from crombach alpha of 0.69, analysis of the wright map obtained item measures and person measures on the wright map showing the distribution of item difficulty and person abilities with limitations logit values 2 to -2 with equivalent person and item positions, so it can be concluded that the instrument can be used to measure the person's ability level.

Efektivitas Problem Based Learning dalam Meningkatkan Kompetensi Siswa pada Pelajaran Perbaikan Peralatan Listrik

This research aims to determine the effectiveness of the Problem Based Learning learning model to improve the competence of class XII TITL students at SMK Negeri 5 Padang. Student learning outcomes are still low caused by teaching factors that are still teacher-centered so that students are not actively involved in the learning process in the classroom. Therefore, it is necessary to conduct research with the application of the Problem Based Learning model to see the effectiveness of students' competence in the cognitive domain. This study uses an experimental research type which is categorized into a pre-experimental research design with a one-group pretest posttest design. The subjects of this study were students of class XII TITL 1 SMK Negeri 5 Padang in the academic year 2022/2023 which consisted of 26 students. To measure this effectiveness, a pretest was given before the implementation of Problem Based Learning to measure students' initial abilities. Then the posttest was given after the learning process of Repair of Electrical Equipment after the implementation of the Problem Based Learning model. The results of the pretest and posttest will be analyzed using classical completeness testing and effect size. The test results show that the value of the students who applied the Problem Based Learning model was higher than the students who did not apply the Problem Based Learning model. Student learning outcomes after implementing Problem Based Learning increase, so that Problem Based Learning is effective for increasing student competence.

TRANSIENT ANALYSIS IN THREE-PHASE ELECTRICAL CIRCUITS WITH DISTRIBUTED PARAMETERS AND INTERFACIAL CONNECTION ON THE EXAMPLE OF HIGH-VOLTAGE CABLE LINE

The analysis of transients in three-phase electric circuits is carried out, which allowed to consider changes of transient components of currents and voltages of each phase of three-phase cable power line and to estimate the level of overvoltage and amplitude of short-circuit currents in screens taking into account transposition. Using the MatLab/Simulink program, software tools and methods for numerical calculation of transient electromagnetic processes in the designed 330 kV cable line were developed to analyze the level of voltages on the screens and currents in the cable cores at different switching modes. The calculations of a specific 330 kV cable line with a length of 13 km, laid for the first time in Ukraine for the power supply of the electric steel complex, were carried out. The calculation of the emerging transient electromagnetic processes in such a line under different conditions of its connection to the three-phase power supply network is carried out. Many types of switching overvoltages are subject to limitation. Feasibility studies of overvoltage protection measures include assessment of statistical characteristics of damage due to damage, simple or extraordinary repair of electrical equipment of the cable line, as well as due to violation of the technological process by consumers. The above determines the relevance of modeling and analysis of electromagnetic processes that occur when connecting and switching cable lines in ultra-high-voltage three-phase electrical circuits. This allows us to recommend the results of work to develop methods for determining the allowable and emergency modes of similar three-phase cable transmission lines and the choice of rational circuit design solutions in their design. Analyzing the transients in the mode of single-phase short circuit, we can conclude that to select the optimal lengths of the transposition sections of cable screens, it is necessary to consider single-phase short circuit mode, as in this mode there are unacceptable overvoltages on cable screens and currents in three-phase cable lines.

Aspects regarding the repair of electrical equipment designed for use in potentially explosive atmospheres

The characteristics providing protection to explosion of equipment designed for use in potentially explosive atmospheres must be preserved during their entire period of life. Repairing is defined as the action to restore faulty equipment to its fully serviceable condition complying with the relevant standard (the standard to which the equipment or parts of equipment were originally designed). Repairing of explosion-proof equipment must be performed considering the prescription of the applicable harmonized standards and the specific type of protection(s) involved. This paper is focused on some particular aspects related to repairing of explosion-proof equipment.

Technical Analysis of Operation Maintenance and Fault Repair of Electrical Equipment in Hydropower Station

Technical Analysis of Operation Maintenance and Fault Repair of Electrical Equipment in Hydropower Station

Brief Introduction of Heavy Industry Electrical Equipment Repair and Equipment Maintenance

Brief Introduction of Heavy Industry Electrical Equipment Repair and Equipment Maintenance

Study on increase of operation efficiency of electrical energy and electrical equipment

This article discusses and reveals the problems of the need for proper use of electricity and electrical installations to improve efficiency. Information on the structure of installed capacity at power plants, the structure of fuel consumption and the consumption of electricity by consumers are reviewed and given; as well as information about the increase in efficiency and causes of failure in operation. Agro-industrial complex consumes about 30 percent of all electricity produced in the country (including the rural population), including pumping stations. This figure is expected to reach 45-50% over the next few years. Thus, the choice, design, installation, maintenance and repair of electrical equipment, which have different forms of ownership and management, but are interconnected by consumers in strict accordance with the rules of electricity consumption, Joint modernization, that is an operating efficiency, remains relevant.

Методология управления ремонтами оборудования в электрических сетях нефтепромыслов

An innovative methodology for managing repairs in distribution networks and power supply systems for oilfield facilities is proposed in this paper. The methodology makes it possible to select optimal solutions in accordance with the priority management goal by formalizing a risk-based model for planning maintenance and repair (M&R) of electrical equipment with a "condition-based maintenance" strategy. One of the main options in the complex of M&R management tasks is an adaptive model of the technological map for the repairs of power facilities, formed in compliance with a number of key principles. The developed model allows you to optimize the volume and complexity of repairs of electrical equipment of a certain type based on the minimum composition of technological operations necessary to eliminate the identified defects. Detection of defects in electrical equipment is achieved by using methods of technical diagnostics and non-destructive testing. In this case, each of the defects is recorded in the defect statement for the object, with the determination of the degree of criticality and fixing a specific type of corrective action. Optimal prioritization of electrical equipment repairs is performed in accordance with the minimum risk function under current restrictions on reliability (an equipment technical condition index) and available resources (total maintenance costs). The originality of the implementation of a key risk event – a power supply failure of an oilfield facility provides calculating the probability and severity of the consequences of an electrical equipment failure taking into account its technical condition and features of the power supply scheme. The given example illustrates the effectiveness of the proposed approach and emphasizes the validity of optimal decisions. The key components of the developed methodology have found practical application in the conditions of real operation of the equipment of oilfield facilities.

ИНФОРМАЦИОННОЕ ОБЕСПЕЧЕНИЕ ПРОЦЕССА РЕМОНТА ЭЛЕКТРОТЕХНИЧЕСКОГО ОБОРУДОВАНИЯ

An example of the development of a relational database for information support for
 the repair of electrical equipment is considered.

Determination of conditions for frequency adjustment of maintenance (M) and routine repair (RR) of electrical equipment under risk-oriented strategy of technical operation

Currently, in order to ensure the required fault-proof level of technological processes in agricultural production, the following strategies among the main ones: afterfailure, planned systematic and a mixed electrical equipment maintenance and repair strategy. The pervasion of information technology in this segment was not widespread. Application of information technologies in conjunction with implementation of risk-oriented strategy is one of the promising directions of electrical equipment maintenance optimization, yet requires adaptation to sectoral characteristics of agricultural production. The article describes the problem of determining the optimal conditions for adjusting the frequency of maintenance and repair of electrical equipment on the basis of risk-oriented approach. To solve this problem, the equation of annual costs for maintenance and repair of electrical equipment was drawn up taking into account the parameter of its failure risk. The relationship between the change of relative risk and the service frequency was established; based on it, the ranges of frequency adjustment of maintenance and ongoing repair were determined.

Контроль качества обслуживания и ремонта электрооборудования железнодорожных переездов

В статье определена роль управления качеством ремонта электрооборудования железнодорожных переездов, рассмотрены основные требования к качеству такого ремонта. Определена ключевая роль контроля при обслуживании и ремонте электрооборудования железнодорожных переездов.

Categorization and gradation of hazardous actions of industrial workers: methodological aspects

The paper defines concepts of “dangerous working conditions” and “dangerous actions of workers”. Regulatory and various doctrinal approaches to differentiating the actions of workers violating labor protection requirements are considered, their specific features, advantages and disadvantages for use in industrial enterprises are analyzed. The author proposes a method of categorizing and grading dangerous actions of workers of industrial enterprises. The method is developed with regard to the specifics of the functioning of oil stores. The work is based on the method of expert assessments, applied in the form of an individual expert survey. The survey was conducted among the experienced specialists of electrical and electrotechnological fields, whose professions and positions are typical of a modern warehouse of petroleum products. The survey results allowed compiling the most objective and complete list of all possible behavioral deviations of a particular professional category of workers. The resulting list is the basis of the reference guide of the developed automated system for personified accounting of the dangerous actions of workers engaged in the operation, maintenance and repair of electrical equipment in oil product warehouses.

The Selecting of Environmentally Friendly Lighting System for Electrical Equipment Repair Shops

Today one of the Federal programs implemented in Russia at the state level, is a program of energy conservation and energy efficiency to reduce the specific consumption of fuel and energy resources. Electricity for lighting accounts for 15% global power consumption and about of 13% power consumption in Russia. The article deals with the approach to lighting systems design on the basis of energy-saving technologies. Switching to energy-efficient lighting is one of the fastest ways to decrease cost of lighting. The paper proposes a new approach to evaluate ecological safety and economic efficiency of three most popular options of the lighting systems. In order to confirm the advantages of this approach to energy savings in industrial premises were undertaken the calculations. The article presents the results of the selection of the most appropriate environmentally friendly lighting system for electrical equipment repair shops using the analytic hierarchy process.

Development of a mathematical model for cost distribution of maintenance and repair of electrical equipment

The research is devoted to the development of a model for cost distribution of maintenance and repair of electrical equipment when making decisions on the management of the electric power system state. The decrease in the reliability of electric power system operation, caused by the objectively existing aging of electrical equipment, requires consideration of equipment significance when planning the maintenance and repair. For this purpose, it is proposed to use the theory of fuzzy sets, Saati’s method and Boolean programming method. The result of solving the optimization problem of multicriteria analysis is a vector of the best alternatives, built on the principle of dominance. The developed algorithm of complex simulation of the electric power system state and cost distribution of maintenance and repair for making decisions on the determination of priority of electrical equipment out of service allows for effective decision­making. The results of probabilistic and statistical simulation of electric power system states using the Monte Carlo method allow us to take into account the probabilistic nature of emergency situations in the electric power system when determining its weakest elements that require priority replacement. The advantage of the proposed approach is taking into account the technical condition of electrical equipment for risk assessment of the electric power system emergency situation. A comparative analysis of ranking results of electrical equipment based on the emergency risk assessment of the electric power system confirmed the high efficiency of the planning of electric power system states when solving the problems of preventive control. The developed model will be used for further research and development of the algorithm for making effective decisions regarding the operation strategy of the electrical equipment and preventive control of the subsystem operation of the electric power system. The obtained results of complex simulation of the electric power system state and technical condition of the electrical equipment give grounds to assert the possibility of software implementation of operation risk analysis of the electric power system for power supply companies

Carbon disulfide exposure estimate and prevalence of chronic diseases after carbon disulfide poisoning-related occupational diseases

BackgroundIn Korea, Carbon disulfide (CS2) toxicity was an important social problem from the late 1980s to the early 1990s but there have been few large-scale studies examining the prevalence of diseases after CS2 exposure discontinuance. So we investigated past working exposure to CS2 characteristics from surviving ex-workers of a rayon manufacturing plant including cumulative CS2 exposure index. Furthermore, we studied the prevalence of their chronic diseases recently after many years.MethodsWe interviewed 633 ex-workers identified as CS2 poisoning-related occupational diseases to determine demographic and occupational characteristics and reviewed their medical records. The work environment measurement data from 1992 was used as a reference. Based on the interviews and foreign measurement documents, weights were assigned to the reference concentrations followed by calculation of individual exposure index, the sum of the portion of each time period multiplied by the concentrations of CS2 during that period.ResultsThe cumulative exposure index was 128.2 ppm on average. Workers from the spinning, electrical equipment repair, and motor repair departments were exposed to high concentrations of ≥10 ppm. Workers from the maintenance of the ejector, manufacturing of CS2, post-process, refining, maintenance and manufacturing of viscose departments were exposed to low concentrations below 10 ppm. The prevalence for hypertension, coronary artery disease, cerebrovascular disease, diabetes, arrhythmia, psychoneurotic disorder, disorders of the nervous system and sensory organ were 69.2%, 13.9%, 24.8%, 24.5%, 1.3%, 65.7%, 72.4% respectively.ConclusionsWe estimated the individual cumulative CS2 exposure based on interviews and foreign measurement documents, and work environment measurement data. Comparing the work environment measurement data from 1992, these values were similar to them. After identified as CS2 poisoning, there are subjects over 70 years of average age with disorders of the nervous system and sensory organs, hypertension, psychoneurotic disorder, cerebrovascular disease, diabetes, coronary artery disease, and arrhythmia. Because among ex-workers of the rayon manufacturing plant, only 633 survivors recognized as CS2 poisoning were studied, the others not identified as CS2 poisoning should also be investigated in the future.

ПРИМЕНЕНИЕ ТЕХНОЛОГИИ LI-FI НА БУРОВОЙ УСТАНОВКЕ

The article considers possibility of information transmission by means of a light flux from a conventional led lamp using Li-Fi technology. This technology is used to unload radio wave radiation, the abundance of which adversely affects the drilling process. Though Li-Fi technology is a super-fast way of data transfer, its application has many nuances that must be considered before using. The positive side of Li-Fi comprises data security, selective coverage of the data transmission area, convenient use during maintenance and repair of electrical equipment, possibility to receive and transmit information in different places. In the context of the study there has been carried out a comparative analysis of efficiency of Wi-Fi and Li-Fi technologies. Possibilities of using modern electronics as a receiver and a transmitter of information with the help of Li-Fi technology are being determined.

ЭЛЕКТРОТЕХНИЧЕСКИЙ КОМПЛЕКС КОНТРОЛЯ СОСТОЯНИЯ АВИАЦИОННЫХ АККУМУЛЯТОРНЫХ БАТАРЕЙ

Urgency of the research. On aircrafts, chemical sources of current are widely used. For example, on helicopters, rechargeable batteries used as buffer and emergency sources.Target setting. In turn, in view of the complex specific operating conditions, it is necessary to monitor the condition of the on-board batteries of aircraft.Actual scientific researches and issues analysis. A number of publications suggest a solution to this problem by checking the status of on-board batteries at the end of flights, and if possible and after each flight, which in real operating conditions takes time to diagnose and is not always possible.Uninvestigated parts of general matters defining. Taking into account that leaded, silver-zinc and nickel-cadmium batteries used as on-board storage batteries, and as practice shows, none of the existing systems of chemical sources of current can fully satisfy all the requirements of various fields of application. In each area, one of the systems may have advantages over others. To assess the condition and efficiency of the systems of chemical current sources of aircraft, it is necessary to take into account their characteristics in the process of monitoring by means of an electrotechnical complex for monitoring the state of aviation storage batteries.The research objective. In this paper, the main purpose of this work is the justification of the need for the application and development of an electrotechnical complex for monitoring the state of aviation batteries.The statement of basic materials. The change in the physical properties of the ambient air affects the operation of the electrical equipment of the aircraft. The tactical and technical requirements for the equipment of aircrafts are designed taking into account the working conditions of electrical equipment and its purpose, including the following indicators: reliability and reliability of work, weight and dimensions, strength of electrical equipment, chemical resistance of electrical equipment, ease of operation and repair of electrical equipment, economic requirements. Proceeding from this, at the end of the flights, and if possible and after each flight, it is necessary to check the degree of discharge of battery batteries and their state (working capacity). In order to detect malfunctions in aircraft batteries, the monitoring of the status of their parameters in all modes of operation performed with the help of the developed control system. Timely detection of battery failures makes it possible to limit their discharge, increase the reliability of the electrical equipment of the aircraft and reduce operating costs.Conclusions. The developed electro-technical complex for monitoring the state of aviation batteries have been proposed for further practical implementation in order to identify malfunctions in the battery in the airborne complexes and ensure constant monitoring of the state of their parameters in all operating modes.