Condition Of Electrical Equipment Research Articles

Online Monitoring of Electrical Equipment Condition Based on Infrared Image Temperature Data Visualization

Temperature is one of the most common indicators for the health of electrical equipment in the substation. By now, infrared thermography has been an important monitoring tool due to its real‐time temperature measurement and noncontact manner. However, at present, portable thermal imagers are usually used to collect and store the status image of single equipment at a certain time, which cannot continuously track the condition of the equipment and the efficiency is very low. In order to solve this problem, our team proposed a method for online condition of electrical equipment based on the visualization and processing of infrared image temperature data. We developed video inspection software, equipped with an infrared camera for automatic inspection to obtain infrared images. After that, the target equipment in a whole image are automatically extracted based on the reference image and the equipment type of each target is classified. Then, in order to visualize temperature data and extract temperature information for different types of equipment, the concepts of heating spot, heating section, and heating area are defined. Finally, diagnosis rules based on relevant related thermal fault diagnosis standards and past experience are proposed to evaluate the condition of each target equipment, using the temperature rise and heat generation percentage. The method has been applied in a real substation and proved its effectiveness. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

ОСОБЛИВОСТІ КОНТРОЛЮ І ДІАГНОСТИКИ ТЕХНІЧНОГО СТАНУ ЕЛЕКТРИЧНОГО ОБЛАДНАННЯ

The article considers the technical possibilities of early detection and prevention of electrical equipment malfunctions. Monitoring the technical condition of electrical equipment is crucial, the quality of such equipment must be extremely high to ensure adequate reliability during operation, and maintenance and adjustment to have high quality indicators. Since the ability to monitor the parameters of electrical systems during their operation is limited and often reduced to monitoring the performance of existing meters, special attention should be paid to quality and comprehensive diagnostics when maintaining such systems. One of the widely used methods of increasing the life of electrical equipment at the stage of its development is the simplification of circuit solutions, respectively, reducing the number of elements in the product. It is known that the fewer individual elements in the product, the less likely it is to fail. Even if complex electrical equipment consists of many elements of high reliability, in general it has low reliability due to the presence of a large number of elements in its design, connected in series. The expediency of increasing the life of electrical equipment at the stage of its development by simplifying circuit solutions, respectively, reducing the number of elements in the product is also limited. The consequence of simplifying the circuit solutions of electrical equipment is quite natural to reduce its functionality. During the operation of electrical equipment should be a constant comprehensive monitoring of its condition and important parameters. Various technical and economic measures are used in the industry to ensure the necessary reliability and trouble-free operation of electrical equipment. We consider it necessary to develop computer models of probability of failure, taking into account the operating conditions and the actual load for each individual electrical device or network.

Determination of the technical condition of electrical equipment in power supply systems

This article describes the methods and means for determining the technical condition of electrical equipment in power supply systems, particularly in transformer substations. There are many ways to determine the technical condition of electrical equipment. However, their implementation requires complex and additional equipment and devices. In addition, these tests must be carried out when the power supply system is off. This will lead to a decrease in the quality of electrical energy. Determination of the technical condition of electrical equipment using thermal imagers is performed under the voltage and in operating modes, the measurement process does not affect the parameters of the power supply system. The results of research in energy enterprises of the Syrdarya region are presented.

Information supply of expert system for assessing operating modes and technical condition of electrical equipment

The article discusses the issues of information and algorithmic support of the expert system for assessing the operating modes and technical condition of electrical equipment. The peculiarities of the considered diagnostic method is the analysis of diagrams that are highly sensitive to insignificant deviations of the values of the signal parameters (current consumption) from the reference values, as well as stability during the analysis period. The results of computer modeling and experimental research of electrical equipment are described in order to obtain a set of reference diagrams. The possibility of using the method in intelligent systems of electrical equipment real-time monitoring is shown.

Assessment of the current technical condition of electrical equipment based on an artificial neural network

Assessment of the current technical condition is an important task, so the state of electrical equipment depends on its further operability. Thanks to modern computing devices, it is possible to implement actively artificial intelligence and computer-assisted learning methods that allow achieving high efficiency in data processing. A study was conducted and an algorithm for diagnosing the technical condition based on an artificial neural network was developed. A model based on a multilayer perceptron is proposed, which allows evaluating the technical condition of a high-voltage power transformer. The result of the technical diagnostics of the model is the assignment of the condition to one of the five classes, proposed by the guidelines presented by the International Council on Large Electrical Systems. The methodology is presented on the example of a 250 MVA transformer with a certain defect history, which allowed us to show the reliability and validity of the obtained results. It is shown that the use of the proposed model makes it possible to achieve accuracy in determining the technical condition of 0.95. The introduction of this model into an automated monitoring and diagnostics system will allow assessing the technical condition of electrical equipment in real time with sufficient accuracy.

Logical-probabilistic assessment of the occurrence of destruction during intersystem interactions in the electrical system of the seaport

This article solves the problem of a quantitative assessment of the occurrence of destruction in the intersystem interactions of the transport system and the electrical system of the seaport, in the conditions of the technological process in the seaport, which indicates its significant impact on the electrical system, as a result of which the reliability of the berthing power line is significantly reduced. The intersystem interactions that occur during the implementation of the technological process, as experience shows, are the causes of critical situations that occur at the border of areas of different physical nature, and the consequences are recorded, in the case under consideration, in the electrical system. A mathematical model describing intersystem destruction in quantitative form is presented in this paper using a logical-probabilistic model that reflects internal and external relationships. In the object under study, the destructive cause (collision) and the consequence (accumulation of electrical damage in the insulation of the cable line) are in the same object (the mooring power supply unit), and this is limited to the effects of intersystem destruction. In such a statement, the object of power supply of the technological process and equipment is considered as a composite object containing a cable line and an electric contact column. The problem being formulated is an important and relevant scientific task, which includes not only the question of identifying the causes of increased electrical wear of the power line, but also the development of methods for obtaining quantitative results, and in practical terms also involves the diagnosis of the technical condition of electrical equipment and timely preventive maintenance.

A technical solution for increasing the reliability of the phase-splitters of AC electric locomotives

Russian Railways OAO is developing a program of the expansion of the Eastern polygon until 2030, the modernization of the transport infrastructure of which is the most important task for the economic and political development of the country. In the near future it is planned to complete the drawing up of a detailed planning schedule of the main stages of construction and parameters of reconstruction of the infrastructure of the Baikal-Amur Mainline and the Trans-Siberian railway. This will not only help to expand access to the markets of the Asia-Pacific region, but will also provide an opportunity to draw more income through an international transit East – West route. The tasks of increasing the reliability of electric rolling stock are brought to the forefront. The implementation of these tasks will reduce the cost of operating and repairing technological equipment. The development of technical means compatible with power supply systems and taking into account the operating conditions of electrical equipment is an urgent task. Power supply of auxiliary machines on all domestic electric locomotives is carried out without the stabilization of the voltage value and balance. At the same time, in order to ensure the reliability of the electric drive motors themselves when operating in the entire range of supply voltage variation, their rated power is increased by 25-50%. Therefore, auxiliary machines on all domestic electric locomotives of alternating current have increased overall dimensions and weight, but the circuit design of the drive system is simple and is presented in the article.

Сhromatographic methods for the study of organic extractants of transformer oil

THE PURPOSE. In order to control the technical condition of oil-filled electrical equipment, a number of new analytical methods have recently been created to determine the ultra-low concentrations of impurity compounds in transformer oil. An analysis of the literature data showed that at this stage of the analytical procedure significant errors may occur that worsen the quality of control of the technical condition of oil-filled electrical equipment, and in some cases make its results meaningless. The published literature practically does not discuss the problem of sample preparation of transformer oil, which negatively affects the quality of analytical control, that is, the reliability of the results and, accordingly, the diagnosis of oil-filled electrical equipment. METHODS. The paper discusses a sample preparation system for transformer oil, which is based on various methods for extracting target components from it. The adsorption process is used, the preparation of chemical derivatives, various types of extraction, liquid, gas, solid phase and fluid, as well as using low temperatures, extraction in microwave, magnetic, electromagnetic and centrifugal fields. It is shown that liquid extraction with an organic solvent is widely used from all sample preparation methods, with the help of which furan compounds resulting from the destruction of paper insulation are extracted from transformer oil. The disadvantages of sample preparation using liquid-phase extraction and the possibility of using solid-phase extraction on various adsorbents for this purpose are discussed. RESULTS. The results of an experimental study of the sorption properties of various organic solvents with respect to porous materials differing in the structure of their surface are presented. We used zeolite-bearing rocks of the Tatar-Shatrashansky deposit, synthetic zeolites NaX-13A. Using the ascending variant of liquid column chromatography, the absolute retention values of standard extractants were determined and their dependence on the length of the sorption layer of the porous material was found. CONCLUSIONS. It was shown that the highest retention times for all studied adsorbents are observed for organochlorine extractants, chloroform, carbon tetrachloride, dichloroethane, trichlorethylene. For N. Hexane is a relatively small interaction. Histograms are given of the effect of the retention time of standard sorbates (extractants) on their physicochemical nature.

Sports training monitoring of energy-saving IoT wearable devices based on energy harvesting

In this paper, energy-saving the Internet of Things wearable devices based on energy harvesting used to monitor sports training. The energy sources involved include radiofrequency energy, mechanical energy, and thermal energy. The power management circuit structure designed to match its application with energy harvesting components as the core to ensure that the collected energy can meet the power conditions of electrical equipment. Completed the hardware design of the entire human motion information collection system based on energy-saving IoT wearable devices, first gave the overall design plan of the system, and on this basis, adopted the modular design of the system, and designed the posture measurement separately unit, positioning unit, and data storage and communication unit. Among them, the attitude measurement unit designed according to the different needs in actual use, and the miniature attitude measurement unit and the multi-function attitude measurement unit are designed. The data storage and communication unit designed to ensure data storage and for the reliability of transmission, an offline data storage unit and a Bluetooth remote communication unit designed respectively. The system adopts a modular design, which makes the system more convenient to expand and upgrade, and has better applicability and reliability.

ОПРЕДЕЛЕНИЕ ПАРАМЕТРОВ СХЕМЫ ЗАМЕЩЕНИЯ ПОГРУЖНОГО ЭЛЕКТРОДВИГАТЕЛЯ НА ОСНОВАНИИ ДАННЫХ ИСПЫТАНИЙ

Одной из основных проблем в процессе эксплуатации скважин, оборудованных установками электрических центробежных насосов, является определение технического состояния погружного электрооборудования и предотвращение его отказов. Среди различных подходов к решению данной задачи можно выделить метод определения технического состояния установки электроцентробежных насосов с использованием полной настраиваемой математической модели установки, включающей модель погружного электродвигателя. Рассмотрен подход к определению и восстановлению необходимых параметров для настройки модели погружного электродвигателя на основании данных,приведённых в протоколе испытанийпогружного электродвигателя. Цель: разработка методики по восстановлению параметров схемы замещения для погружного электродвигателяна основании типовых данных, содержащихся в протоколе приёмо-сдаточных испытаний. Методы. Предложенный подход основан на совместном использовании настраиваемой динамической модели асинхронного электродвигателя с короткозамкнутым ротором и алгоритмом дифференциальной эволюции. Фактически решение задачи по определению параметров схемы замещения погружного электродвигателясводится к решению задачи глобальной оптимизации, т.е. к задаче на поиск глобального (наилучшего) минимума функции. Результаты.Разработан подход для восстановления параметров схемы замещения погружного электродвигателя, который позволяет устанавливать приемлемые для практики значения параметров схемы замещения для погружного электродвигателяпо результатам испытаний; проверена работоспособность разработанного подхода идентификации с применением методов глобальной оптимизации и математического моделирования погружных асинхронных электродвигателей; полученные оценки являются устойчивыми для всех параметров схемы замещения кроме параметра механической подсистемы.

The most common violations of regulatory indicators of the quality of electric energy in electric networks

Work on ensuring the quality of electric energy in accordance with the requirements of GOST 32144-2013 is currently relevant and requires prompt and high-quality solutions. The article lists the main consumers of electric energy that negatively affect its quality, provides the results of measurements of electric energy quality indicators and the most common violations of regulatory requirements, analyzes the influence of voltage asymmetry on the operating conditions of electrical equipment. The basic formulas for calculating the asymmetry coefficients and ways to reduce the voltage asymmetry are proposed.

Temperature Compensation Method for Infrared Detection of Live Equipment under the Interferences of Wind Speed and Ambient Temperature

Infrared thermal imaging technology plays an important role in evaluating the operating condition of electrical equipment. This article focuses on two critical environmental factors, namely, wind speed and ambient temperature. They interfere with infrared detection and fault diagnosis by affecting the actual temperature of the fault area. In this article, we use the principle of heat transfer to explore the affected conditions and the changing laws of diagnostic indicators. We provide a solution for diagnosing the live equipment fault area after compensating for the infrared temperature. Both the simulation and experimental results show that the method can obtain the temperature of the equipment fault area under different environmental conditions for different electrical equipment failures when they meet the temperature compensation conditions. The method can eliminate the influences of wind speed and ambient temperature on the results of infrared temperature measurement and achieve a unified solution to the problem of multiple types of electrical equipment. This breaks through the barriers of infrared temperature measurement applications limited by the on-site environmental conditions. The proposed method can serve to further improve the existing evaluation standards. The results of the article are useful for troubleshooting equipment and improving the accuracy of the infrared diagnosis of live equipment.

ANALYSIS OF CONSTRUCTION PRINCIPLES AND FUNCTIONALITY OF HIGH-VOLTAGE POWER TRANSFORMER CONDITION MONITORING SYSTEMS

The article presents the results of analysis of construction principles and functionality of systems used to monitor the condition of high-voltage power transformers. The main functions of modern monitoring systems used to diagnose the condition of electrical network equipment both in Ukraine and abroad were analysed. Based on the analysis it was found that the most characteristic functions of monitoring systems are the detection of rapidly developing defects and continuous control of parameters necessary to predict and assess the state of equipment. It is shown that efficiency of monitoring systems will be determined by both accuracy of measuring instruments and adequacy of prediction and diagnostic models used in the process of measurement results processing. Requirements to the equipment which observance allows providing effective and economically reasonable use of monitoring systems are considered. The typical architecture of modern monitoring systems is analysed, the basic elements of such systems are considered. Basic levels of information flow processing within the systems for monitoring the condition of power transformers have been considered. A detailed description and justification for using diagnostic parameters for monitoring the main components of power transformers such as dissolved gases analysis, partial discharges, current, voltage and power of transformers, oil temperature in different transformer locations, switching and atmospheric overvoltages, short-circuit currents, deformation of windings and others are presented. The output parameters returned by monitoring systems are given. The introduction of modern systems and technical means of monitoring the condition of high-voltage power transformers will reduce the risks of emergencies and, consequently, reduce the economic losses associated with the replacement of damaged transformers and under-release of electrical energy.

TECHNICAL DIAGNOSTIC SYSTEM FOR ELECTRIC MOTOR TESTS

Diagnosing the condition of electrical equipment during its manufacture, repair and preventive inspections is an integral part of the technological process. Devices for diagnostics are required by enterprises of the industrial and energy complex, railway and sea transport, mining, concentrating and pulp and paper mills, repair plants, etc.In serial and mass production, the desire to automate the production process as much as possible is natural, which also includes the stage of testing electric machines. Studies have shown that the complexity of control operations is up to 15% of the complexity of the manufacture of electric motors. The average time norms for conducting acceptance tests of one electric machine of average power make 3 ... 35 hours. The average time for processing the results of acceptance tests of one machine is 0.6 ... 4 hours. Naturally, such a high complexity of testing and processing their results makes us look for ways to automate testing.Electric motors are usually designed for a service life of 15... 20 years without major repairs, provided they are properly operated. Proper operation means operation in accordance with the nominal parameters specified in the passport data of the motor. However, in practice there is a significant deviation from the nominal modes of operation. These are, first of all, low quality of supply voltage and violation of rules of technical operation: technological overloads, environmental conditions (the raised humidity, temperature), decrease in resistance of isolation, cooling disturbance.The consequence of such deviations are emergency modes of operation of electric motors. In some subsectors of industry, the accident rate of electric motors ranges from 20 to 50% per year. Failure of the electric motor leads to severe accidents and significant material damage due to downtime, the cost of repairing the consequences of accidents and repair of the failed electric motor. Repair of an electric car with a capacity of 1 kW costs 250-300 UAH. To estimate the cost of repairing a more powerful machine, you need to multiply this figure by the engine power. In addition, operation in emergency modes leads to increased power consumption and increased reactive power consumption.

Diagnostics of the technical condition of electric network equipment based on fuzzy expert estimates

The paper describes a new possible method of diagnostics of the current technical condition of equipment using a mathematical model based on fuzzy expert estimates and the theory of fuzzy sets. The specifics of the task is determined mainly by the type of the obtained estimates, namely: causal relationships between the controlled parameters of the transformer equipment and defects that could entail their change and the possibility of further operation of the facility. At the same time, attention is paid to the problem of the degree of consistency of expert opinions that affects the quality of the assessment of the current technical condition of the studied object. The paper provides a comparative analysis of the arithmetic mean estimates and median estimates of the consistency of expert opinions. It is shown that the significant drawback of the arithmetic mean approach is its instability towards outliers of individual opinions moving the resulting value under the influence of the “dissident expert opinions”. On the other hand, the median estimate is free of such shortage; it is more outlier-resistant and simply discards a part of radically outlying expert opinions. For the first time, the Kemeny median has been used for technical diagnostics. Kemeny median is based on the introduction of a metric to the set of expert opinions, and axiomatic introduction of the distance between them. Also, the paper formulates a criterion on how to determine the optimal number of experts in the group.

The Concept of Efficient Control of the Condition of Electrical Equipment According to Nondestructive Testing Data

The problem of developing an effective system for controlling the condition of electrical equipment in the conditions of the transformation of the modern electric power industry is investigated. The classification of approaches to the equipment condition control depending on the degree of using the available information is presented. An option of forming the equipment condition control function based on “flexible” strategies and nondestructive testing technology is proposed. The conceptual model developed describes the principles of structural and functional interaction of procedures for controlling the equipment’s key technical parameters, the predictive diagnostics of its condition, and the assessment and planning of its subsequent operation within the framework of procedures of integrated logistics support over the short or long term. The scenarios of developing criteria for making control decisions during operation of electrotechnical equipment based on the results of nondestructive testing taking into account the actual category of its condition and the requirements of regulatory and technical documentation are considered. An example of using this approach at oil extraction facilities is given. The development of the proposed conceptual solutions is considered as a possibility to improve the technical and economic efficiency of the equipment operation procedures, including the construction of new-generation electric power grids.

Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin.

The application of wide band-gap power electronic devices brings more challenges to insulating packaging technology. Knowing the influence of applied voltage parameters on insulation performance is helpful to evaluate the insulation condition of electric power equipment. In this paper, the effect of repetitive square wave voltage duty cycle on the growth characteristics of electrical trees in epoxy resin was studied. The experimental results show that the square wave voltage duty cycle has a significant influence on treeing features. The electrical tree proportion initiation has shown a decreasing trend, and the shape of the electrical tree changes from pine-like to branch-like by increasing the duty cycles. The length and damaged area of electrical tree increased with the increase in the duty cycle up to 10% and then decrease by increasing the duty cycle higher than 30%. It indicates that a low duty cycle will enhance the electron injection and accumulate space charges and thus accelerate electrical tree development. Under short duty cycles, the electric field due to the shielding effect near the needle tip suppresses the electrical tree growth, which results in treeing growth stagnation. The obtained results are helpful to keep these parameters in mind during the design of epoxy-based insulation such high-voltage rotating machines and power electronic device packaging.

Rh-doped h-BN monolayer as a high sensitivity SF6 decomposed gases sensor: A DFT study

The SF6 decomposed gases sensor is crucial for detecting insulation condition of electrical equipment. To study applicability of metal-doped two-dimensional (2D) nanomaterials for gas sensors, density functional theory (DFT) calculations based on first-principle theory were used for investigating adsorption properties, sensitivity and electronic behavior. In this study, Rh-doped h-BN (Rh-BN) monolayer was first proposed to analyze adsorption of typical SF6 decomposed gases, including H2S, SO2, SOF2, SO2F2. The stable structure of Rh-BN monolayer was studied by four possible sites. The binding energy (Eb) of stable structure is −1.204 eV. Meanwhile, the adsorption energy (Ead) and sensitivity of SF6 decomposed gases show that Rh-BN monolayer has ideal adsorption and sensing properties than other materials. Moreover, the analysis of density of state (DOS) and band structure illustrate the sensing mechanism and further prove the applicability of Rh-BN monolayer for SF6 decomposed gases. The above calculations and analysis would be significant to explore Rh-BN monolayer as a novel SF6 decomposed gases sensor for electrical equipment insulation.

Diagnóstico energético em uma empresa do segmento de metalurgia

This article presents the results of the energy diagnosis carried out in a company in the segment of metallurgy and commercialization of metals with personalized cuts. This diagnosis has the main objective of evaluating the conditions of electrical installations, equipment, general infrastructure, lighting and air conditioning systems, in addition to the behavior and awareness of employees regarding the efficient use of energy. The survey of the data was carried out through a technical visit and application of questionnaires with the company's employees, which helped to understand the ‘culture’ of electricity use, as well as the policies, existing or not, of consumption adopted by the company. Another aspect of the questionnaire aims to obtain data on the equipment used that makes it possible to technically evaluate them. Along with the application of the questionnaire, a visual analysis of the equipment and electrical installations was also carried out, making the written record, in order to provide a better basis for the diagnosis. The results showed that the company's lighting system is undersized, according to the measurements made with the lux meter and that most of the lamps used are fluorescent, which are less efficient when compared to LED lamps. In this sense, there is a concern of the company, since in some environments the lamps have already been replaced by others with this technology. With regard to air conditioning, there are some oversized environments, so that the company could obtain savings if it used the appropriate air conditioning unit. As for awareness, it was found that there is a need to systematize and formalize the actions to obtain the benefits with the implementation of energy conservation actions, the implementation of a CICE is suggested.

Estimating the failure probability of an instrument transformer cell in the high voltage distributing device using an expert-statistical method

The approach has been developed to determining the numerical value of a failure probability and to forecasting the resource of an instrument transformer cell at the time of observation. Underlying a given approach is the control over the main parameters that affect the technical condition (TC) of an instrument transformer cell in the distributing device of high voltage (DDHV). To determine a TC of the devices, a mathematical method of fuzzy modeling has been applied, which makes it possible to integrate the diagnostic parameters that are different in their nature. Building a fuzzy model involved the experience of experts in the relevant industry. The relevance of the development of a given approach is predetermined by the functional importance of a current transformer. Its performance affects the accuracy of triggering the relay protection devices, as well as the accounting of electrical energy. Precise accounting of electric energy implies minimizing its losses and shows the path to energy savings. A special feature of this approach is that it takes into consideration the influence of TC of each piece of cell equipment on the probability of its failure in general. To account for the factors of random disturbances, an expert fuzzy model is refined by the probabilistic-statistical method. An example of the DDHV instrument transformer cell in an electric-energy system has been used to substantiate the advantage of a given approach over the existing methods to control the technical condition of electrical equipment. The error in predicting the cell resource based on one parameter (thermal imaging examination) was Δ f(D-02) =1–Q D-02 =0.364, or 36.4 %. When applying an expert-statistical model for determining the probability of a cell failure, the error was Δ f(D-02) =1–Q apost =0.034, or 3.4 %. The application of a given approach has produced a more reliable estimate of the probability of cell failure. Implementing the developed approach in the field of electrical equipment diagnosing could improve the reliability level of forecasting results. The constructed model could be applied in the automated systems that diagnose on-line the DDHV electric devices