Deterioration Of Equipment Research Articles

Deterioration of Porcelain Insulators Utilized in Overhead Transmission Lines: A Review

Reliability of a power system is generally designated as a measure of the ability of the system to provide customers with adequate and constant supply. Power system failure have adverse effects and become a great concern for important large scale industries in South Korea such as semiconductors, steel and chemicals which require a high quality, stable power supply. In South Korea, nearly 80% of transmission system failures are caused by either natural eventualities such as lightning strikes or failure of insulators. Ageing assets pose significant challenges for utilities. Moisture with high temperature, fluctuation in temperature, contamination and electric stress accelerates aging in suspension insulators. The primary goal for the utility is to utilize the full life of an asset, but ageing increases the probability of deterioration and failure of equipment. The average age of vital assets, is estimated to be more than 35 years. In South Korea near about 1,223,538 porcelain insulators are reported to be in functional state. Among them only 65.19% of insulators are reported to be in operative state over 35 years. Insulators demand only 5–8% of installation costs. However, it demands more than 50% of maintenance costs. Thus, deterioration of insulator enhances capital expenditure and decrease returns on the asset base. Therefore, insulators should possess excellent electrical aging resistance to prevent deterioration of insulators. Korea Electric Power Corporation (KEPCO), largest power generation and distribution utility in South Korea utilize porcelain for almost all suspension insulators employed in transmission lines. Porcelain insulators are usually employed in transmission system as they are cost-effective and possess near about 30 to 60 years of lifespan. Lifetime evaluation of porcelain insulators in overhead transmission line is absolutely challenging, owing to aging process. This work highlights investigation of various failures of suspension type porcelain insulators, influencing factors responsible for degradation in lifetime and deterioration of suspension type insulators, various laboratory test methods available for evaluation of insulators employed in overhead transmission lines.

Maintenance Cost Index for Egyptian Hotels: An Exploratory Study

In the hotel industry maintenance is important despite of its complex processes as its effectiveness will directly affect the quality of hotel service and have direct effect on guests' impression of the hotel. in the same time, the costs of operating and maintaining the hotel engineering systems must be properly monitored and controlled in particular the in-house manpower, out-source contracts, energy consumption and equipment deterioration. There are limited literatures available regarding the hotel maintenance cost analysis, This is what urged the researcher to conduct this study which aims to develop a hotel maintenance cost index, to compare hotel maintenance costs and the distribution of this cost over the different maintenance approaches and in-house and out-sourced strategies among the three, four, and five-star hotels. The quantitative research methodology of the interview was conducted with hotel's chief engineer or maintenance supervisor in three, four, and five-star hotels in Egypt (via-phone interview). The study revealed an index benchmark number that could be used to compare maintenance operations cost in three, four, and five-star hotels which also could be used in planning hotels maintenance expenditures if we know the value of this expenditure in other hotel categories.

Deep heterogeneous GRU model for predictive analytics in smart manufacturing: Application to tool wear prediction

Smart manufacturing arises the growing demand for predictive analytics to forecast the deterioration and reliability of equipment. Many machine learning algorithms, especially deep learning, have been investigated for the above tasks. However, long-term prediction is still considered as a challenging issue. To address this problem, this paper presents a hybrid prediction scheme accomplished by a newly developed deep heterogeneous GRU model, along with local feature extraction. Specifically, to capture the temporal pattern hidden in the sequential input, a local feature extraction method is designed by integrating expertise knowledge into the deep learning model for enhanced feature learning. Next, an intermediate layer is designed in the deep heterogeneous GRU model structure to capture the inherent relation for long-term prediction. The proposed model is optimized by systematic feature engineering and optimal hyperparameter searching. Finally, experimental studies on tool wear test are performed to validate the superiority of the presented model over conventional approaches.

Maintenance Scheduling of Power Equipment Considering Opportunistic Maintenance Strategy

This paper investigates the impact of opportunistic maintenance strategy on power equipment maintenance scheduling under economic dependence. The model focuses on power equipment with two types of failures: random failure and deterioration failure. Unlike previous research which didn’t consider opportunistic maintenance between different failures modes, opportunistic maintenance strategy is proposed in this paper. In the opportunistic maintenance strategy, whenever random failure occurs, decision has to be made on whether deterioration failure is preventively maintained based on the degree of equipment deterioration and economic dependence. Firstly, Markov process is used to describe equipment state-space diagram. And then, in order to determine the optimal inspection rate, preventive maintenance threshold and opportunistic maintenance threshold of power equipment, the analytical expressions of inspection cost, maintenance cost, repair cost and outage cost are quantified. Finally, the total cost is minimized to get the optimal maintenance strategy. Case studies demonstrate the feasibility of the proposed model.

Short-term Power System Maintenance Scheduling with Imperfect Repair

Most of the existing research in short-term power system maintenance scheduling assumes that repair is minimal when equipment fails. However, this may not always be the truth because sometimes repair after failure is imperfect. This paper investigates the impact of imperfect repair on power system maintenance scheduling. Unlike previous research which didn’t consider imperfect repair, a condition-based maintenance optimization model is proposed. The model focuses on equipment deterioration failure. Firstly, a new equipment state-space diagram under imperfect repair is given. And then, the availability of power equipment considering maintenance schedule and imperfect repair is derived using the Markov process theory. Based on that, in order to determine the optimal equipment maintenance schedules, the expression of system outage cost is given. Finally, system outage cost is minimized to optimize equipment maintenance schedules. A case study is used to illustrate the effectiveness and significance of the proposed model.

Diesel-Injection Equipment Parts Deterioration after Prolonged Use of Biodiesel

The application of biodiesel blends is known to significantly affect operation of diesel-injection equipment, especially the injectors and fuel pump. This paper summarizes experience on this subject from burning fuel blends with high-percentages of biodiesel (up to 70%) on a common-rail, high-pressure-injection diesel engine and a conventional DI engine. Both engines were unable to start after running for 100 h each and staying shut off for more than two months. In order to understand the wear characteristics of the injector nozzle, pump pistons, and elastomer parts (in the case of the high-pressure pump of the common-rail engine), due to the prolonged operation with high-percentage biodiesel blends, their injectors and pumps parts were examined and compared by performing normal photography and low magnification microscopy. Additionally, the various elastomer parts of the high-pressure fuel pump of the common-rail engine were examined for wear and deterioration. The results are compared with existing literature results from other researchers. The observed deterioration of diesel-injection equipment is caused by use of high-percentage biodiesel blends and subsequent engine shut down.

Integrated maintenance and production decision fork-out-of-nsystem equipment with attenuation of product quality

PurposeEquipment reliability significantly impacts productivity, and in order to obtain high equipment reliability and productivity, maintenance and production decision should be made simultaneously to keep manufacturing system healthy. The purpose of this paper is to investigate the joint optimization of equipment maintenance and production decision fork-out-of-nsystem equipment with attenuation of product quality and to explore the impact of maintenance on the production and cost control for manufacturers.Design/methodology/approachA multi-period Markov chain model fork-out-of-nsystem equipment is set up based on the assumption that the deterioration of equipment is a pure birth process. Then, the maintenance cost, setup cost, inventory holding cost, shortage cost, production cost and the quality cost are analyzed with the uncertain demand and the attenuation of product quality stemmed from equipment deterioration. The total lowest cost per unit time and its specific calculation method are presented. Finally, the robustness and flexibility of the method are verified by a numerical example and the effects of equipment deterioration intensity and attenuation of product quality are analyzed.FindingsThe result shows that the joint decision model could not only satisfy the uncertain demand with low cost and strong robustness but also make the output products high quality level. In addition, the attenuation of product quality would influence the equipment maintenance and production decision and leads to the production waste and increases the operation cost greatly.Originality/valueImplications derived from this study can help production maintenance managers and reliability engineers adequately select maintenance policy to improve the equipment efficiency and productivity with high quality level at a relatively low cost.

Some Features of Non-Safety Costs in Maintenance of Work Equipments

In the present research article, a modest attempt has been made to find some important features non-safety costs in maintenance of work equipments. The preventive maintenance is essential in maintaining the safety and reliability of work equipment, which is ensuring the safety and health of workers and also it, give an optimal and safe working environment. Here, we analyze the influence of the failure of the work equipment, as a result of non-preventive maintenance, on the managerial performance of a company. From the analysis of the effects of the costs of work-related events, it was found that the failure and deterioration of work equipment accounted a significant share from the cost of non-safety. These factors are an argument for the cost - benefit analysis of occupational safety and health. Final, we emphasized some important role of preventive maintenance, namely the necessity to carry out periodic safety tests, starting from the conception of many employers that they have the economic criterion regarding the safety and health of the workers in the work process.

Influence of Deterioration of Machinery and Equipment on the Dynamics of their Market Value

Influence of Deterioration of Machinery and Equipment on the Dynamics of their Market Value

Availability and Maintenance Modeling for GIS Equipment Served in High-Speed Railway Under Incomplete Maintenance

Gas-insulated substation (GIS) equipment served in the traction power-supply system (TPSS) of the high-speed railway (HSR) suffers from extremely severe traction load conditions during its lifetime. In this paper, three major issues related to the actual field maintenance operations of GIS equipment in TPSS are addressed: 1) $s$ -dependent degradation and shock process; 2) both spatial and temporal failure thresholds of shocks; and 3) incomplete maintenance (i.e., nonignorable maintenance time). To model the deterioration and failure process of GIS equipment, the hard failure model and the soft failure model are proposed. The characteristic function is utilized to bridge the s -dependent degradation and shock process in the soft failure model, while the extreme shock model (with spatial threshold) and $\delta $ -shock model (with temporal threshold) are introduced in the hard failure model. Furthermore, the index of availability, which combines both reliability and maintainability, is derived under the incomplete maintenance consideration. Based on the balance of availability and maintenance cost, the maintenance strategy with periodic inspections for GIS equipment in the long-run time span is developed. Optimizations of three decision parameters (i.e., inspection period, extreme shock threshold, and $\delta $ -shock threshold) are implemented to achieve the best performance (with high availability and low maintenance cost) of the maintenance strategy.

National Planning and Policy Improvement for ABC Patients in Kyrgyzstan

Background and context: Breast cancer takes the first place among the cancer diseases in the Kyrgyz Republic. Almost 40% of breast cancer cases are detected in the advanced III and IV stages. Specialized oncology services for cancer patients are available in two oncology centers in the Kyrgyz Republic. One is in Bishkek (capital of the country), and another is in Osh (the second large city). However, medical services provided by the government are limited to the surgery, particularly, with mastectomy. Radiotherapy is not available because of deterioration and breakdown of equipment. Mandatory Health Insurance Fund does not cover chemotherapy cost for cancer patients, and patients pay out of pocket. Kyrgyz National Essential Drug List does not include many vital antineoplastic agents recommended by WHO. The absence of essential antineoplastic agents in National Essential Drug List negatively affects medicine registration and procurement, makes them unavailable, inaccessible and unaffordable in Kyrgyzstan. Advanced breast cancer patients cannot plan their upcoming expenses. Many patients can´t finish the full course of treatment. Ergene is the only organization in Kyrgyzstan that advocates and provides technical assistance to the Oncology Institute and the Ministry of Health to improve access to oncological drugs for the treatment of breast cancer. Aim: Improve access to oncology medicines and treatment of patients with advanced breast cancer. Strategy/Tactics: Ergene team accessed National Essential Drug List (EDL) and selected available oncology drugs. Then the experts compared available oncological drugs from the National EDL and oncology drugs from the WHO list. Together with oncologists, experts analyzed the availability of essential drugs for advanced breast cancer and identified missing drugs to be included in National EDL. These drugs are trastuzumab, anastrozole, paclitaxel, and gemcitabine. Program/Policy process: The team of experts calculated the cost of treatment of breast cancer regimens including therapy with trastuzumab and started negotiations with Mandatory Health Insurance Fund (MHIF) for chemotherapy treatment coverage. The policy makers agreed that the cost of basic chemotherapy regimens is affordable for insurance coverage (adriamycin cyclophosphamide-245 USD, cyclophosphamide methotrexate fluorouracil - 390USD, fluorouracil adriamycin cyclophosphamide -426 USD). However, the cost of monotherapy regimen is more expensive (capecitabine, docetaxel -2400 dollars) and requires additional financial resources. Outcomes: MHIF will include coverage of essential AC, FAC, and CMF regimens for women with breast cancer and will consider partial coverage of trastuzumab and several monotherapy regimens. What was learned: Chemotherapy regimens cost calculation is an integral part of advocacy and policy work. It helped to negotiate chemotherapy treatment insurance coverage for women with breast cancer.

Studies on the Deposit Structure in the Cooling Systems of Steam Turbines at TPPs

When untreated natural water is used in the reverse cooling systems with tower-shaped evaporative cooling stacks of thermal power plants, negative processes occur, namely sparingly soluble substance deposition onto heat-exchange surfaces, corrosion, sludging of flow paths, bio-fouling, etc., which significantly worsens the thermal efficiency of TPPs as a whole, leads to equipment deterioration, and worsening hydrodynamic performance. This paper is devoted to the study of the physicochemical structure of deposits formed in reverse cooling systems of thermal power plants using IR spectroscopy and elemental analysis. At the Kazan TPP-3 with a conjugated reverse cooling system, samples of deposits have been taken from the rotary chamber and the condenser tubes of a turbine as well as from the sprayers of a tower-shaped evaporative cooling stack. The analysis of IR spectra of the samples showed that the base of deposits in the tower-shaped evaporative cooling stack consists of calcium carbonate that includes iron compounds (mainly hematite Fe2O3), inorganic sulfates, silicates, magnesium carbonate. Dense parts of the deposits in the condenser of turbines consist of iron silicate with the impurities of other substances. The deposits in the reverse cooling system are most intensely formed in the areas with the highest heating temperature, such as turbine condensers and spraying nozzles in the tower-shaped evaporative cooling stack. At the Naberezhnye Chelny TPP, the deposits have been taken from a forechamber gate of the reverse cooling system. In total, four different samples of deposits that differ in appearance from each other have been chosen. As shown by infrared spectroscopy, the main part of deposits is formed by the corrosion products of metal structures coated with the layers of sparingly soluble compounds, including calcium and magnesium carbonates, iron oxides, silicates, and organic compounds, such as humic substances.

OA259] Development of a quality assurance program for B-mode ultrasound equipment: One – year experience

Purpose Though ultrasound imaging is a technique operating without the use of ionizing radiation, still quality control of the equipment is important. Performance evaluation can lead to identification of image quality degradation that, if not early detected, will probably result in misdiagnosis or missed-diagnosis and will eventually lead to wrong clinical decisions. The purpose of this study is the creation and implementation of a quality assurance (QA) program for B-mode ultrasound equipment in our hospital. Methods An extensive literature review was performed in order to identify QA guidelines for ultrasound equipment established by professional bodies and authorities such as the American Association of Physicists in Medicine (AAPM), the British Medical Ultrasound Society (BMUS), the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) and the American Institute of Ultrasound in Medicine (AIUM). QA protocols established in individual hospitals and clinics from United Kingdom, United States, Italy, Finland and Korea were also identified and included in our study. A QA program for B-mode ultrasound equipment in our hospital was created and implemented in a (1) Toshiba SSA660A system installed in 2013 and a (2) Siemens Acuson X700 installed in 2017. Results The QA protocol created consists of the following parts: mechanical inspection and electrical safety, image uniformity, penetration depth, vertical and horizontal distance accuracy, anechoic object imaging, axial and lateral resolution, dead zone, image contrast, monitor fidelity and processor quality indicator. The preliminary results from the implementation of this program and our one-year experience will be presented. Conclusions Quality assurance of ultrasound equipment is of great importance as it can prevent clinical errors in patient diagnosis. The QA procedures can detect malfunction of the equipment and image quality deterioration and assure diagnostic efficacy and patient safety. In our hospital a QA protocol was developed in order to ensure correct operation of ultrasound systems. Future steps include the development of a QA protocol for Doppler ultrasound systems and its further implementation.

Method for increasing oil resources transformers with longterm operation

AnnotationEstimates of the technical condition of equipment of power plants and substations are presented in the paper. They are associated with a high degree of deterioration of the power grid equipment, which affects the state and operating conditions of the equipment. The degree of these mutual influences and their laws can only be established with a general assessment of the state of entire equipment of the power grid facility. The selection of a rational system for the repair of power oil transformers of distribution substations involves a problem with multiple variables, based on the concept of reliability, aging, renewal and industrial diagnostics. It is recommended to conduct a comprehensive method of repair organization based on the individual observation by the Consumer for changes in the technical condition of the equipment during operation and the quantitative evaluation of the technical condition of the transformers with respect to the set of diagnostic parameters.

Development of a Method for Predicting Deterioration of Plan Equipment

Development of a Method for Predicting Deterioration of Plan Equipment

Development of a Method for Predicting Deterioration of Plant Equipment

Development of a Method for Predicting Deterioration of Plant Equipment

Bearing Diagnostics of Hydro Power Plants Using Wavelet Packet Transform and a Hidden Markov Model with Orbit Curves

The contribution of a medium‐sized hydro power plant to the power grid can be either at base load or at peak load. When the latter is the most common operation mode, it increases the start and stop frequency, intensifying the hydro turbine components’ degradation, such as the guide bearings. This happens due to more frequent operation in transient states, which means being outside the service point of the machines’ nominal condition, consisting of speed, flow, and gross head. Such transient state operation increases the runner bearings’ mechanical vibration. The readings are acquired during the runner start‐ups and filtered by a DC component mean value and a wavelet packet transform. The filtered series are used to estimate the relationship between the maximum orbit curve displacement and the accumulated operating hours. The estimated equation associated with the ISO 7919‐5 vibration standards establishes the sojourn times of the degradation states, sufficient to obtain the transition probability distribution. Thereafter, a triangular probability function is used to determine the observation probability distribution in each state. Both matrices are inputs required by a hidden Markov model aiming to simulate the equipment deterioration process, given a sequence of maximum orbit curve displacements.

DATA PROCESSING DURING CONDITION BASED MAINTENANCE OF RADIO ELECTRONIC EQUIPMENT

The paper deals with the problem of necessity substantiation of statistical data processing procedures in case of radio electronic equipment operation. These procedures are used in case of realization of preventive maintenance at the use of operation strategy according to the condition with control of diagnostic variables. The basic elements of typical operation system for radio electronic equipment are considered in the paper. The analysis of models for typical elements of operation system is carried out. Radio electronic equipment is the main element of operation system, therefore the problem of statistical data processing was considered for the model of diagnostic variables trend for this equipment. The model is adopted for diagnostic variables trend, which belongs to the type of random processes with changepoint. The steady-state period of diagnostic variables trend is characterized by a random duration, which is described by normal probability density function. The period of technical state deterioration of radio electronic equipment is described by a sum of a linear function with deterministic but unknown inclination angle and uniform random variable. The quantitative estimation of data processing efficiency (availability coefficient and average operation costs) was determined by simulation modeling. The simulation results showed that there is an optimal value of preventive threshold, at which the resource costs are minimal. This result can be explained by existence of a balance between costs for repair and maintenance.

An unsupervised feature extraction method for nonlinear deterioration process of complex equipment under multi dimensional no-label signals

The nonlinearity in complex equipment, such as turbofan engine and electric motor, is a substantial factor. The nature of complex equipment deterioration refers to a nonlinear deterioration process. An unsupervised feature extraction method based on greedy kernel principal components analysis (GKPCA) is proposed for nonlinear deterioration process under multi dimensional no-label signals. The 21 signals of turbofan engine and 6 signals of electric motor are analyzed using the method, respectively. The results show that: taking the first component as deterioration feature of complex equipment in system-level is appropriate; the more exact deterioration features with better performance in monotonicity, robustness and computation speed, are identified from GKPCA-PC1, thus the features can be used for online monitoring and warning of complex equipment; the unsupervised feature extraction method considering nonlinearity is more effective and efficiency for deterioration level identification and health management such as adding lubricant grease at optical time to prevent Over-alarm. The results verify the effectiveness and efficiency of the method in dealing with nonlinearity in deterioration feature extraction of complex equipment. Through the study, it reveals that considering the substantial nonlinearity in complex equipment is important for extracting more exact deterioration feature under multi dimensional no-label signals.

ECONOMIC EFFICIENCY OF MODERNIZING THE EQUIPMENT FOR THERMAL POWER PLANTS

The subject matter of the study is the economic efficiency of modernizing equipment for thermal power plants (TPP). The goal of the study is to identify the economic efficiency of modernizing the equipment of the TPP basing on new technology and taking into account cost minimization and environmental requirements. The subject of the study is the theoretical and practical aspects of the economic efficiency of equipment modernization. To find a solution of this problem, the feasibility analysis was used to determine the current state of TPP equipment and the indicators of the parameters of old and new equipment as well as to introduce new equipment, which enables burning low-grade and waste coal in a circulating fluidized bed (CFB). The issues of energy as the industry that covers energy resources, extraction, transformation, transfer and use of various types of energy are considered. The features of an electric power station, as a set of installations, equipment and tools which are used directly for producing electric energy are highlighted as well as the necessary facilities that are located on a designated area. The features of the structure of the technology of thermal power plants are illustrated. The place of thermal power plants in the structure of power engineering is considered. The available problems of thermal power plants are revealed. The solution of problems of low efficiency, the deterioration and ageing of thermal power plants equipment is suggested. The indicators of the equipment of thermal power plants are given. The advantages and disadvantages of the old technologies used in thermal power plants of Ukraine are studied. The disadvantages of outdated equipment such as damage and constant need for reconstruction are regarded. The mechanism of introducing the new technology of the circulating fluidized bed (CFB) in comparison with the traditional flaring at domestic and foreign thermal power plants is analyzed. The advantages and disadvantages of the CFB technology in comparison with traditional flaring are considered. The results of the feasibility study are presented; these results provide the basis for determining the most promising objects for the implementation of this technology while retooling power plants. The effect of modernizing the equipment of thermal power plants is proved. Solutions for improving the cost-effectiveness of thermal power plants are suggested. The results of the obtained decision within this study are illustrated.