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A New Model for Reliability-Centered Maintenance Prioritisation of Distribution Feeders
... Power ENS [23][24][25], VOLL [23], LS [26][27][28][29][30][31][32], TWLS [32], RAW [13], Power delivered [13,15] Duration Restoration Time [33], SAIDI [24,25], CAIDI [34] Frequency Frequency of service disconnection [35], SAIFI [24,25], DIC [35] Probability Probability of supply interruptions, probability of power not delivered [13], EENS [14,25] Consequence Economic ENS cost [27], load shedding cost [9], customer outage cost [23,33], VOLL cost [34] ...
... Power ENS [23][24][25], VOLL [23], LS [26][27][28][29][30][31][32], TWLS [32], RAW [13], Power delivered [13,15] Duration Restoration Time [33], SAIDI [24,25], CAIDI [34] Frequency Frequency of service disconnection [35], SAIFI [24,25], DIC [35] Probability Probability of supply interruptions, probability of power not delivered [13], EENS [14,25] Consequence Economic ENS cost [27], load shedding cost [9], customer outage cost [23,33], VOLL cost [34] ...
... Power ENS [23][24][25], VOLL [23], LS [26][27][28][29][30][31][32], TWLS [32], RAW [13], Power delivered [13,15] Duration Restoration Time [33], SAIDI [24,25], CAIDI [34] Frequency Frequency of service disconnection [35], SAIFI [24,25], DIC [35] Probability Probability of supply interruptions, probability of power not delivered [13], EENS [14,25] Consequence Economic ENS cost [27], load shedding cost [9], customer outage cost [23,33], VOLL cost [34] ...
Extreme weather events are one of the main causes of large-scale power outages in distribution systems. The changing climate has led to an increase in the frequency and severity of these events, which, if not mitigated, are expected to lead to more instances of widespread outages and the severe societal and economic damages that ensue. Protecting the power grid against such events, which are high impact yet low frequency, requires a paradigm shift in grid design practices. In recent years, many researchers have focused on the resilience of the power grid against extreme weather events by proposing various grid hardening and/or redundancy solutions. The goal of this paper is to provide a survey of the literature related to the infrastructural resilience of the power grid against extreme events. Currently, no standard definitions or metrics exist for power grid resilience, and researchers adopt various models for quantifying and assessing it. Hence, a review of the most commonly used definitions and metrics for resilience is provided first, with a discussion of their advantages and disadvantages. Next, the paper presents an extensive and critical review of the solution methodologies proposed in the literature for improving the infrastructural resilience of the power grid. The shortcomings of the current solution methods and gaps in research are identified, followed by a discussion of the future directions in research.
... However, the RCM application requires experience and a step-by-step decision-making by using heuristic approaches that can result in large amount of time to collect the required data (Endrenyi et al. 1998). The RCM policy is applied to evaluate maintenance plans for EDS in Afzali et al. 2019, where an importance level is defined for main distribution feeders through a weighting index. An importance level is also assigned to equipment in feeders. ...
... Such indexes can be obtained from historical data, mathematical expressions that model the system behavior or probability distributions. Several indexes are distributed among the papers of literature, but it can be pointed out that few works consider diverse indexes in a comprehensive manner to plan maintenance actions in EDS (Afzali et al. 2019;Mirsaeedi et al. 2017aMirsaeedi et al. , 2017bMohammadnezhad-Shourkaei et al. 2011;Yssaad et al. 2014;Wang et al. 2014). ...
... In Billinton and Grover (1975), equations are formulated to model system reliability indexes. Most recently, a weighting index is proposed by Afzali et al. (2019) to obtain priority levels for main distribution feeders and equipment under the RCM policy. Moreover, a decision-making process on maintenance of distribution branches to improve reliability is presented in (Arya 2016), by applying a weighted importance factor that classifies branches under their failure severity including load and distributed generation effects. ...
Electric distribution systems have the objective of supplying electricity with quality and reliability to the final consumers. In order to meet both criteria, efficient maintenance programs have a vital importance mainly due to the actual increase in the requirements for distribution service quality and in technologies related to electrical networks. In this sense, the number of options and criteria for developing effective programs makes the related decision-making process a complex task. This paper presents a comprehensive review on maintenance planning in electrical distribution systems covering different criteria such as economic and reliability. More specifically, this work summarizes contributions up to now through a holistic framework that comprises the premises of predictive, preventive and corrective maintenance. The work is organized by relevant aspects of researches in the field, as criteria, probability functions, constraints and methods that have been applied, within a comprehensive classification.
... In [18], a multi-objective problem is considered with the aim to balance preventive and corrective maintenance in power distribution networks. In [19], [20], the authors introduce an index to prioritize interventions in a power network as a weighted combination of indices (e.g., the frequency and the duration of a fault); the approach in [19] does not discuss how to calculate the weights, while in [20] they are chosen in order to normalize the indices being summed. In [21] a multi-criteria decision approach to prioritizing maintenance is considered where the criticality of different component of a power network are evaluated based on several indices, composed via Fuzzy AHP. ...
... In [18], a multi-objective problem is considered with the aim to balance preventive and corrective maintenance in power distribution networks. In [19], [20], the authors introduce an index to prioritize interventions in a power network as a weighted combination of indices (e.g., the frequency and the duration of a fault); the approach in [19] does not discuss how to calculate the weights, while in [20] they are chosen in order to normalize the indices being summed. In [21] a multi-criteria decision approach to prioritizing maintenance is considered where the criticality of different component of a power network are evaluated based on several indices, composed via Fuzzy AHP. ...
The business continuity of services provided by Critical Infrastructures is vital in order to ensure the security, the economy and the public’s health of a Nation. Delays and bad recovery strategies after disasters or failures can lead to impairing impacts in terms of injury to people, environmental pollution and loss of time, money and resources. In such a context, the adoption of a spatial Decision Support System (DSS) might play a crucial role in order to help operators to adopt the best recovery strategy in the shortest possible time frame. Current approaches do not consider the problem of assigning an intervention location to a maintenance crew and do not account for the effective time needed for emergency intervention. In this paper we develop a novel spatial multi-criteria DSS methodology for prioritizing repair interventions on power networks. The multi criteria strategy is solved by the adoption of Incomplete Analytic Hierarchy Process (AHP) which computes holistic assignment costs as the result of the combination of multiple and possibly conflicting metrics of cost.Then, we use the holistic costs as the basis for a task assignment phase that is based on the Hungarian algorithm. The proposed strategy has been implemented as a module in the Decision Support System, namely Critical Infrastructure Protection Risk Analysis and Forecast (CIPCast), whose outputs are represented on a web-based Geographic Information System (GIS) platform. The effectiveness of the proposed multi-criteria strategy has been validated via a real case study on the Rome City electrical distribution network.
... El valor de cada índice de confiabilidad se normaliza en el mismo rango teniendo como base el mayor valor entre SAIFI, SAIDI. Luego de haber obtenido los índices de confiabilidad normalizados se procede a obtener el CIC normalizado de cada alimentador, a continuación, se divide el CIC normalizado para cada índice de confiabilidad normalizado, de esta manera obtenemos los coeficientes de ponderación K 1 , K 2 , K 3 y K 4 que se los pueden obtener de las siguientes expresiones (13) (Afzali et al., 2019) Con la finalidad de obtener un algoritmo donde su estructura tenga inmersa los efectos de los índices de confiabilidad más relevantes y costos, se presenta el índice WI el cual da la ponderación de criticidad de los elementos a considerar para una acción de mantenimiento, el modelo de índice propuesto se lo expresa en la ecuación (14) (Afzali et al., 2019) El índice ponderado WI debe ser calculado para cada alimentador y la priorización del mantenimiento estará en función del resultado obtenido, mientras más elevado de el resultado WI menor será la confiabilidad por consiguiente su condición es más crítica y la prioridad para el mantenimiento será mayor. ...
... El valor de cada índice de confiabilidad se normaliza en el mismo rango teniendo como base el mayor valor entre SAIFI, SAIDI. Luego de haber obtenido los índices de confiabilidad normalizados se procede a obtener el CIC normalizado de cada alimentador, a continuación, se divide el CIC normalizado para cada índice de confiabilidad normalizado, de esta manera obtenemos los coeficientes de ponderación K 1 , K 2 , K 3 y K 4 que se los pueden obtener de las siguientes expresiones (13) (Afzali et al., 2019) Con la finalidad de obtener un algoritmo donde su estructura tenga inmersa los efectos de los índices de confiabilidad más relevantes y costos, se presenta el índice WI el cual da la ponderación de criticidad de los elementos a considerar para una acción de mantenimiento, el modelo de índice propuesto se lo expresa en la ecuación (14) (Afzali et al., 2019) El índice ponderado WI debe ser calculado para cada alimentador y la priorización del mantenimiento estará en función del resultado obtenido, mientras más elevado de el resultado WI menor será la confiabilidad por consiguiente su condición es más crítica y la prioridad para el mantenimiento será mayor. ...
Los registros de fallas que poseen las empresas eléctricas de distribución, son las desconexiones o salidas del servicio en un alimentador, las cuales presentan un sin número de eventos funcionales que se ven reflejados en la parte operativa como económica, hasta la actualidad son temas que no se han logrado solucionar íntegramente para mitigar estos tiempos de desconexión, por eso el mantenimiento en una empresa de distribución de energía eléctrica se ha convertido hoy en día, en una de las actividades de toma de decisiones más importantes debido a la necesidad de aumentar la confiabilidad, calidad y seguridad de suministro de energía eléctrica al cliente final. Por lo cual, este estudio presenta una metodología para priorizar la identificación de alimentadores por su nivel de criticidad, la cual es posible obtener mediante el índice propuesto de confiabilidad ponderada WI. Una vez calculado este indicador para cada alimentador de la subestación analizada, se puede priorizar una acción de mantenimiento a los alimentadores con los valores más elevados.
... On the contrary, the maintenance practices should be performed on critical components due to limitations in the allocated budget. In this regard, [7,10,11] contribute significantly to the criticality identification of transmission and distribution equipment. Reference [10] does the same practice to minimize costs at two different levels, and [11] improves an optimal maintenance plan for transformers in this regard: the related reliability indices, the TC, and lifetime were specified using the conventional Markov model and actual service data. ...
... In this regard, [7,10,11] contribute significantly to the criticality identification of transmission and distribution equipment. Reference [10] does the same practice to minimize costs at two different levels, and [11] improves an optimal maintenance plan for transformers in this regard: the related reliability indices, the TC, and lifetime were specified using the conventional Markov model and actual service data. Also, [12] considered the elements' failure rates by proposing a preventive maintenance (PM) approach to decrease the probability of failures and decrease costs. ...
On the topic of power systems, the most critical assignment would be providing facilities to make electricity available at the lowest price with a fulfilled level of reliability for all consumers. Today, power transmission reliability has received more concentration due to the increasing essence of providing high‐quality energy to customers and operating competitive conditions in electricity markets. In this regard, this paper scrutinizes the reliability‐centred maintenance (RCM) issue in terms of considering two optimal maintenance strategies for transmission assets to decrease their forced outage rate (FOR). This techno‐economic budget‐based maintenance is a probabilistic approach to help asset managers and experts in the decision‐making process: to determine between maintenance strategies with associated costs and provide the most economical resource allocation for these elements, which leads to an improvement in the reliability of the whole network. Decreasing the average probability of Energy Not‐Supplied (ENS), the simulation determined the proper maintenance strategy for transmission components. After that, the repercussions of the fallen ENS will be analyzed in total maintenance cost (MC), operation cost (OC), and the system's total cost (TC). Also, the IEEE 24‐bus reliability test system is considered as a case study demonstrating the proposed technique's practicality.
... On the other hand, (Afzali et al. 2019) introduced a new weighted importance (WI) reliability index model and presented a method to prioritize the components of the distribution system for reliability-centered maintenance (RCM) at two different levels. Two different models of passive PM (to minimize the maintenance costs) and active PM (to maximize the profit) for renewable energy resources systems are proposed in Mazidi and Sanz (2017). ...
... The effect of weighting coefficients is clearly observable in this Figure. The proposed method has been compared to recent work (Afzali et al. 2019) that introduced a weighted importance (WI) reliability index model and Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
Reliability and accessibility of distribution systems are important goals that have significant impacts on the costs. The proper strategy of maintenance based on components arrangement and assets is the best way to reach these goals. This strategy is a kind of uses reliability-centered maintenance (RCM). Due to the limited maintenance budget, performing maintenance activities for all components of the system is neither possible nor logical. So most of the resources should be allocated to the most critical and important components. This paper presents a novel analytical method of prioritization of distribution systems’ components by introducing a new weighted cumulative Reliability-based diagnostic importance factor. This new factor includes different reliability indexes in form of diagnostic factors and will show that the order of components obtained by this method is better than another method in saving the budget and providing reliability of the system. The process of decision-making for prioritization of distribution systems’ components based on their criticality degree will both improve the reliability level of the total system and decrease the cost of load interruption and finally maintenance costs. The proposed model is implemented on a radial distribution network. Numerical results show the effectiveness of the proposed RCM model for micro-grids.
... In [9] a game theory method is applied in the RCM context to assess the contribution of every single piece of equipment to the whole system reliability under different loading conditions and high-order contingencies. In [10] a weighted importance reliability index is proposed to prioritize the elements of an electric distribution system in an RCM framework. In [11] the lifetime of main components involved in a smart distribution grid is analyzed and a probability model for the lifetime is proposed. ...
... Benefits of an RCM approach far exceed those of any type of maintenance program and it has been widely used by the aircraft, oil and gas, spacecraft, or nuclear industry [16]. However, the use of RCM is relatively new in industries outside of these areas [4][5][6][7][8][9][10]16]. RCM strategies and their impact on electrical power systems are still undefined due to the lack of evidence and current applications. ...
Reliability assessment in traditional power distribution systems has played a key role in power system planning, design, and operation. Recently, new information and communication technologies have been introduced in power systems automation and asset management, making the distribution network even more complex. In order to achieve efficient energy management, the distribution grid has to adopt a new configuration and operational conditions that are changing the paradigm of the actual electrical system. Therefore, the emergence of the cyber-physical systems concept to face future energetic needs requires alternative approaches for evaluating the reliability of modern distribution systems, especially in the smart grids environment. In this paper, a reliability approach that makes use of failure modes of power and cyber network main components is proposed to evaluate risk analysis in smart electrical distribution systems. We introduce the application of Failure Modes and Effects Analysis (FMEA) method in future smart grid systems in order to establish the impact of different failure modes on their performance. A smart grid test system is defined and failure modes and their effects for both power and the cyber components are presented. Preventive maintenance tasks are proposed and systematized to minimize the impact of high-risk failures and increase reliability.
... Reliability aspects like increased complexity represented by the interconnection and interoperability between different types of systems are an additional aspect to consider in the smart grid context and motivates the exploration of new approaches to assess the smart grid operational reliability. In this context, Reliability Centered Maintenance (RCM) has been a solution proposed in recent years and applied to electric power systems [4][5][6][7][8][9][10][11]; RCM combines the reliability evaluation and maintenance planning [5,[12][13][14][15][16]. ...
... Benefits of an RCM approach far exceed those of any type of maintenance program and it has been widely used by the aircraft, oil & gas, spacecraft or nuclear industry [17]. However, the use of RCM is relatively new in industries outside of these areas [4][5][6][7][8][9][10][11]. RCM strategies and their impact on electrical power systems are still undefined due to the lack of evidence and current applications. ...
Reliability assessment in traditional power distribution systems has played a key role in power system planning, design, and operation. Recently, new information and communication technologies have been introduced in power systems automation and asset management, making the distribution network even more complex. In order to achieve efficient energy management, the distribution grid has to adopt a new configuration and operational conditions that are changing the paradigm of the actual electrical system. Therefore, the emergence of the cyber-physical systems concept to face future energetic needs requires alternative approaches for evaluating the reliability of modern distribution systems, especially in the smart grids environment. In this paper, a reliability approach that makes use of failure modes of power and cyber network main components is proposed to evaluate risk analysis in smart electrical distribution systems. We introduce the application of Failure Modes and Effects Analysis (FMEA) method in future smart grid systems in order to establish the impact of different failure modes on their performance. A smart grid test system is defined and failure modes and their effects for both power and the cyber components are presented. Preventive maintenance tasks are proposed and systematized to minimize the impact of high-risk failures and increase reliability.
... To evaluate and verify the single line diagrams of critical feeders, the identification of single line diagrams is conducted. Previous research involved selecting the critical feeder and then identifying the critical component within the feeder (Afzali et al., 2019). ...
... A Maintenance schedule was proposed for the offshore wind asset. They determined optimal individuals and grouped various maintenance schedules and various parameters were considered for this purpose [15]. A maintenance policy was selected policy by applying a fuzzy ANP approach [16]. ...
Asset or equipment reliability and availability have occupied extensive attention because of an emerging competitive environment and the overall operating and production cost. The main focus of this manuscript is to prioritize the lean tool and select an appropriate maintenance strategy for the repairable assets in the maintenance shop of the SIMGA1 shipyard. Five (5) assets of that maintenance shop such as an air compressor machine, 500-ton press machine, overhead crane machine, VDF lathe machine, and Roller machine were under breakdown maintenance. Due to the continuous degradation of those assets, attempts should be taken to enhance the reliability parameters by predicting upcoming failure events for each equipment or asset. QFD-AHP is a rapid tool in which quality function deployment is integrated with AHP to make an optimal selection. Firstly, the integrated QFD-AHP method is employed to prioritize the lean tools for that maintenance shop. 5S and KPI are the best fit for that shop among ten lean tools. Non Homogenous Poisson Process (NHPP) is a model which represents the no. of failure experienced up to time (t). NHPP and Weibull analysis are utilized to predict future failure events and analyzed the nature of the failure accordingly. From the results of the Weibull analysis and NHPP analysis, it is shown that the slope (β) of the failure rate is greater than 1 for all assets. Overhead crane m/c and 500-ton press m/c are the most critical m/c according to equipment criticality analysis. Finally, a decision diagram is utilized to extract the most congruent maintenance strategies based on the reliability parameter of five (5) assets. The approach employed in this study helps maintenance practitioners to achieve lean maintenance.
... There are indices of reliability that is often used in assessing the power supply reliability is ASAI (Bai et al., 2015), SAIDI (Meier et al., 2019), EENS (Groissböck and Gusmão, 2020). ASAI is the customer hours of available service divided by total customer hours demanded, representing the proportion of the time that the system can supply power; SAIDI is the average power outage duration of all users in 1 year, representing the average time of power outage per user caused by the system; EENS is the expected energy load that is not delivered at the load point in the demand side because of unexpected power outages, representing the amount of power that the system cannot supply (Afzali et al., 2019;Eryilmaz et al., 2021;Koh et al., 2015;Prajapati and Mahajan, 2021). These three indicators can reflect the power supply reliability from different points of views and dimensions, which can more clearly and directly reflect the power supply reliability. ...
Emergency power system refers to a system that is composed of self-generating equipment in the building. By providing power support for emergency events such as power outages, it can keep the energy safety assurance. Usually, emergency power systems are independent and redundant. As a backup, their utilization rates are extremely low, resulting in excessive redundancy causing a lot of waste of resources and equipment. In this paper, a model integrating stand-alone emergency power systems with micro-network was proposed to improve power supply reliability in a more economic manner. Integrated emergency power system with the dispatch strategy of self-priority was established based on reliability and power demand of buildings simulated through Monte Carlo method. To evaluate the impact of integration, the total cost of integrated emergency power system was calculated including economic loss during power outages and system costs. Finally, genetic algorithm was used to obtain the optimal capacity and dispatch strategy of the integrated emergency power system by minimizing the total cost. Results showed that the reliability was improved, and the total cost was reduced to 80.05% by integrated emergency power system in the illustrated case.
... The number of subway vehicles in operation continues to increase, and the proportion of subway vehicle maintenance costs in the total operation and maintenance costs is constantly increasing. How to improve the maintenance economy of subway vehicles and reduce maintenance costs is a problem, and it is necessary for the majority of scholars to study it [2]. Subway vehicles mainly use daily inspections, monthly balanced repairs, annual scheduled repairs, 5 years or 800,000 vehicle kilometers for frame repairs, 10 years or 1.6 million vehicle kilometers for major repairs and temporary repairs [3,4]. ...
The current maintenance mode of the subway vehicle traction system does not consider the change of failure rate in the operation of components, and there is an unreasonable maintenance interval and high maintenance cost. To solve this problem, a dynamic preventive maintenance strategy for subway vehicle traction systems considering stages is proposed. Service age decreasing factor and failure rate increasing factor are introduced to build a new dynamic reliability model considering the effect of preventive maintenance on component failure rate. Non-preventive failure maintenance, preventive maintenance, preventive update maintenance and opportunistic maintenance are adopted. For the components in degradation or random failure stages, a preventive maintenance optimization model with the least maintenance cost, constrained by reliability, is established. The maintenance strategy is optimized and solved based on the enumeration method to obtain single-component irregular preventive maintenance intervals and multi-component group preventive maintenance times. The results show that the proposed maintenance models are reasonable and feasible. On the premise of ensuring the system reliability, the number of vehicle outages for maintenance and the maintenance cost are reduced. Feasible and effective maintenance models and methods are provided. They can ensure the reliability of subway vehicles and reduce maintenance costs. The effectiveness and economy of maintenance work is increased.
... Su foco está orientado a mantener la función del sistema más que en restaurar al equipo a una condición ideal (Eriksen, Utne, y Lützen, 2021). Esto lleva a la definición formal siguiente: proceso que se usa para determinar lo que debe hacerse para asegurar que un activo físico continúe desempeñando las funciones deseadas en su contexto operacional presente (Moubray, 1997;Ben-Daya, Kumar y Murthy, 2016;Afzali, Keynia y Rashidinejad, 2019). SAE International (2009) define al MCC como una filosofía de gestión de mantenimiento en la cual un equipo de trabajo multidisciplinario establece las actividades más efectivas en función de la criticidad de los activos, teniendo en consideración los posibles efectos que originan sus modos de fallo en la seguridad, el ambiente y las funciones operacionales. ...
Correo electrónico: yanely88@nauta.cu aramisll@uclv.edu.cu arypadron@nauta.cu RESUMEN La necesidad de reorientar los estudios referentes al tratamiento de las fallas operacionales en la planta de tuberías hidráulicas motiva a establecer como objetivo de la investigación la aplicación del Mantenimiento Centrado en la Confiabilidad al equipamiento de dicha planta en la Empresa de Producciones Varias de Ciego de Ávila, como vía para asegurar el desempeño deseado de la Gestión de mantenimiento en la empresa. En la investigación se estudian y realizan análisis operacionales a cada una de las partes del flujo productivo mediante la utilización de técnicas como la observación directa, la tormenta de ideas, la valoración de indicadores y el criterio de expertos. Como principales resultados se obtienen el levantamiento de los elementos básicos de un programa de Mantenimiento Centrado en la Confiabilidad, la confección de un plan de mantenimiento para los equipos estudiados y la estimación del impacto económico productivo de las tareas que conforman dicho plan de mantenimiento en los indicadores de desempeño de la empresa. Palabras clave: Análisis de criticidad, Mantenimiento Centrado en la Confiabilidad (MCC), Plan de mantenimiento. ABSTRACT The need to reorient the studies referring to the treatment of operational failures at the hydraulic pipeline plant motivates to establish as a research objective the application of Reliability Centered Maintenance to the equipment of the plant at the Empresa Producciones Varias of Ciego de Avila, as a way to ensure the desired performance
... Reliability Centered Maintenance (RCM) is a method of maintenance analysis that systematically establishes the appropriate maintenance tasks for assets at optimal frequencies to maintain the appropriate functions required during certain periods [5][6][7]. RCM regulates maintenance policies at the plant or equipment type level. RCM is a more structured way of using the best methods [8]. ...
Marine Loading Arm (MLA) supports all liquid bulk loading and unloading activities, especially imports of chemical raw materials such as NH3, H2SO4, and H3PO4. Therefore, to minimize the occurrence of failure it is necessary to have a treatment method. Reliability Centered Maintenance (RCM) is a maintenance method that focuses on increasing the reliability of components in the system. The RCM uses the principle of risk management to determine tasks and maintenance schedules appropriately. The RCM process is implemented using American Bureau Shipping (ABS) Guidelines. According to the results of this research, there are three types of maintenance tasks for MLA, in which category A has 14 maintenance tasks, category B has 21 maintenance tasks, and there are no maintenance tasks in category C. In all maintenance categories for Preventive Maintenance by 54% with 19 tasks, for Condition Monitoring of 37% with 13 tasks, while for Run-To-Failure of 9% with 3 tasks.
... However, there is a need to ascertain the extent to which distribution reliability is affected by violating these limits using established reliability-assessment techniques. Many authors have investigated the effect of different maintenance strategies on system reliability, proposing different approaches aimed at minimising the cost of maintenance while delivering the best reliability results by focusing on critical components [16][17][18][19]. To make appropriate decisions regarding maintenance, reliability modelling considering component lifetime models is required to more accurately quantify the reliability benefits from implementing different reliability-centred maintenance (RCM) approaches. ...
Electricity-distribution network operators face several operational constraints in the provision of safe and reliable power given that investments for network area reinforcement must be commensurate with improvements in network reliability. This paper provides an integrated approach for assessing the impact of different operational constraints on distribution-network reliability by incorporating component lifetime models, time-varying component failure rates, as well as the monetary cost of customer interruptions in an all-inclusive probabilistic methodology that applies a time-sequential Monte Carlo simulation. A test distribution network based on the Roy Billinton test system was modelled to investigate the system performance when overloading limits are exceeded as well as when preventive maintenance is performed. Standard reliability indices measuring the frequency and duration of interruptions and the energy not supplied were complemented with a novel monetary reliability index. The comprehensive assessment includes not only average indices but also their probability distributions to adequately describe the risk of customer interruptions. Results demonstrate the effectiveness of this holistic approach, as the impacts of operational decisions are assessed from both reliability and monetary perspectives. This informs network planning decisions through optimum investments and consideration of customer outage costs.
... However, there is a need to ascertain the extent to which distribution reliability is affected by violating these limits using established reliability assessment techniques. Many authors have investigated the effect of different maintenance strategies on system reliability proposing different approaches aimed at minimising the cost of maintenance while delivering the best reliability results by focusing on critical components [16][17][18][19]. To make appropriate decisions regarding maintenance, reliability modelling considering component lifetime models is required to more accurately quantify the reliability benefits from implementing different reliability-centred maintenance (RCM) approaches. ...
Electricity distribution network operators face several operational constraints in the provision of safe and reliable power given that investments for network area reinforcement must be commensurate with improvements in network reliability. This paper provides an integrated approach for assessing the impact of different operational constraints on distribution network reliability by incorporating component lifetime models, time-varying component failure rates as well as the monetary cost of customer interruptions in an all-inclusive probabilistic methodology that applies a time-sequential Monte Carlo simulation. A test distribution network based on the Roy Billinton test system is modelled to investigate the system performance when overloading limits are exceeded as well as when preventive maintenance is performed. Standard reliability indices measuring the frequency and duration of interruptions, and the energy not supplied are complemented with a novel monetary reliability index. The comprehensive assessment includes not only average indices but also their probability distributions to adequately describe the risk of customer interruptions. Results demonstrate the effectiveness of this holistic approach as the impacts of operational decisions are assessed from both reliability and monetary perspectives. This informs network planning decisions through optimum investments and consideration of customer outage costs.
... In [19], an integrated Fuzzy BWM-TOPSIS framework was addressed to prioritize feeders for inspection and maintenance purposes. A weighted sum approach was presented in [20] to prioritize distribution feeders based on reliability indicators. In [21], researchers addressed a mathematical model to prioritize generation unit components through investigating the effect of failure costs on the system by game theory. ...
Asset management is employed in power distribution companies to compensate for financial restrictions. Developmental proposals to be efficient should be made based on priorities, which are usually determined according to the security status of the system. This paper proposes twofold schemes to identify critical power distribution feeders for future secure operation, according to three criteria, i.e., voltage drop, losses, and feeder loading margin. The multi-criteria decision-making (MCDM) concept is utilized for this purpose. As the first proposed scheme, the fuzzy Best-Worst method (FBWM) is used to weight system criteria through experts’ judgments. Outcome weights are utilized to prioritize feeders via the VIKOR technique. For the second scheme, simultaneous evaluation of criteria and alternatives (SECA) as another new approach is employed to weight criteria and rank feeders at the same time without relying on experts’ opinions. Finally, the results of integrated FBWM-VIKOR and SECA are compared with the other MCDM methods to verify the effectiveness of proposed approaches.
... Obviously, the larger the factor, the upper the place in the priority list of maintenance for component and it means more budget should be spent for PM applying on them. In one of the new papers [37], the defined factor creates an interesting balance between important types of reliability indices including SAIFI, SAIDI and EENS. In the weighted factor (WI), the three important indices were each linked to their weighting coefficient that derived from the cost of losing load, while considering the feature of the series and the parallelism of the components. ...
Abstract Security and continuous proper functioning of the power system is a vital issue for supplying demands. Providing an acceptable level of reliability and necessity of that in all parts of the power system, from generation to distribution, has always been, and remains a major concern for network managers. Asset management and performing regular and routine maintenance activities has a considerable impact on ensuring system reliability, reducing expensive crashes, and preventing shutdowns. Up to now, much research has been done on the proper planning of maintenance in different parts of the network with a focus on cost savings, improved system performance and reliability, and reduced shutdowns. The purpose of this article is to review the findings of the study and to provide a more comprehensive view of the maintenance planning issue.
... In [31], the RCM method was presented with the aim of optimally allocating the total maintenance budget for EDN feeders. The maintenance budget for feeders was practically allocated to decrease the failure rate of the EDN feeders, and in [32], the feeders were prioritised with two different levels (first level without RCM planning and second level with RCM planning) to improve the reliability Index. ...
Reliability improvement is a fundamental issue in electric distribution network (EDN) operation. In this regard, providing the most efficient maintenance policy can dramatically assist the electric utility companies in reducing the failure rate of EDN components. In the present study, a novel probabilistic reliability‐centred maintenance (RCM) approach is proposed in which the reliability level of the EDN components are evaluated according to the three‐state Markov model (MM). Using the MM, this study presents a trade‐off between the corrective maintenance and the preventive maintenance (PM) actions and finally determines the precedence of EDN components in PM financial resource allocation. Through the method presented in this study, the financial resources of the PM are economically allocated with regards to economic parameters such as customer outage costs and budget constraints. The efficacy of the proposed RCM approach is evaluated through the implementation of the RCM approach on bus number four of the well‐known Roy Billinton test system.
... Finally, the best maintenance strategy for each critical component is selected by identifying the lowest total cost of different maintenance strategies. Afzali et al. (2019) presented a new weighted importance (WI) reliability index model and proposed an appropriate method in order to prioritize the elements of distribution system for RCM at two different levels. At the first level, the feeders of a sample distribution substation are prioritized for the RCM actions. ...
Purpose
The purpose of this study is to propose a hybrid reliability-centered maintenance (RCM) approach for mining transportation machines of a limestone complex, a real case in Esfahan, Iran.
Design/methodology/approach
Criteria for selecting critical machines were collected within literature and selected by decision-makers (DCs), and critical machines have been identified using the preference ranking organization method for enrichment of evaluations (PROMETHEE). Also, multi-criteria decision-making (MCDM) methods were used in addition to failure mode, effects and criticality analysis (FMECA) for selecting and prioritizing high-risk failures as well as optimizing the RCM performance. More specifically, the criteria of severity, detectability and frequency of occurrence were selected for risk assessment based on the previous studies, and were weighted using the analytic hierarchy process (AHP) method. Also, the technique for order of preference by similarity to ideal solution (TOPSIS) has been applied to prioritize failures' risk. Finally, the critical failures were inserted in the RCM decision-making worksheet and the required actions were determined for them.
Findings
According to the obtained values from PROMEHTEE method, the machine with code 739-7 was selected as the first priority and the most critical equipment. Further, based on results of TOPSIS method, the failure mode of “Lubrication hole clogging in crankpin bearing due poor quality oil,” “Deformation of main bearing due to overwork” and “The piston ring hotness due to unusual increase in the temperature of cylinder” have the highest risks among failure modes, respectively.
Originality/value
RCM has been deployed in various studies. However, in the current study, a hybrid MCDM-FMECA has been proposed to cope with high-risk failures. Besides, transportation machineries are one of the most critical equipment in the mining industry. Due to noticeable costs of this equipment, effective and continuous usage of this fleet requires the implementation of proper maintenance strategy. To the best of our knowledge, there is no research which has used RCM for transportation systems in the mining sector, and therefore, the innovation of this research is employment of the proposed hybrid approach for transportation machineries in the mining industry.
... In the power system industry, Afzali et al. [20] presented new weighted importance (WI) reliability index model. They proposed an applicable method to rank the components of the RCM distribution system for RCM at two different levels. ...
Reliability-Centred Maintenance (RCM) is a strategic process to improve the maintenance planning of companies which contributes to sustainable production. This method has been applied by numerous industries to achieve an efficient maintenance process, but many have not fully completed their goals. The reason for this failure is that RCM implementation is complex, and organisations need to have adequate preparations before they implement it. In the pre-implementation phase, it is necessary to know the number of Critical Success Factors (CSFs) as a critical measure for implementing the RCM method successfully. Therefore, it is important for practitioners to apply a symmetric mechanism involving fuzzy systems to achieve the desired RCM implementation. There are a limited number of studies that have observed these factors regarding the characteristics of oil and gas companies, especially in the pre-implementation phase. Addressing RCM pre-implementation issues is of high importance from the economic perspective of sustainability for oil and gas organisations. The objective of this study is to investigate significant items in RCM pre-implementation through a combination of quantitative and qualitative analyses. The Nominal Group Technique (NGT) method is applied by gaining the opinion of experts to determine the factors and prioritising them using mathematical modelling. A group of related experts from the oil and gas industry were initially interviewed and surveyed to determine the critical success factors. These identified factors were then analysed using quantitative analysis to identify the important degrees and scored using Fuzzy Analytic Network Process (FANP). Fifteen major factors affecting the criticality of successful RCM implementation have been identified and prioritised, based on their weights. The model proposed in this study could be used as a guideline for assessing CSFs in other countries. To apply the proposed model in different contexts, it needs to be modified according to the needs, policies, and perspectives of each country.
... Focusing primarily on the first stage, identifying the most critical components in the system can recast as a decisionmaking problem, which can be quantitatively or qualitatively approached. Quantitative methods include mathematical representation of the system model, complex evaluations, and investigation of the impacts of all components failures on the system operation and performance [8]- [13]. Quantitative methods, however, may not be applicable to systems for which the models are either extremely complex or are not completely available [14]. ...
With the limited availability of resources and time in the power industry, condition-based maintenance schemes are deemed effective to maintain the system desirable performance at all times. In this context, reliability centered maintenance is the key to strategically manage the assets in power grids enforcing the performance metrics to be the system reliability indicators. To this end and to most effectively allocate the maintenance time and resources, the most critical components in the grid, i.e., those needing maintenance the most with massive failure consequences, should be first identified. This article proposes a new multicriteria decision-making scheme to identify critical feeders in power distribution systems. Unlike the previous efforts which have focused on techniques based on the analytical hierarchical process, a best-worst method is employed in this article to prioritize the system reliability criteria based on the experts’ knowledge and judgments. The proposed approach can achieve a faster and more accurate outcome in prioritizing the system criteria for maintenance. In addition, fuzzy theory is utilized to address the prevailing uncertainties in the experts’ judgments and decisions. Finally, TOPSIS technique is employed to prioritize distribution feeders for future inspection and maintenance allocation.
... There are several steps in the RCM stage [9], [10], [11], [12], [13]: ...
PT. A is a company engaged in the manufacture of Crude Palm Oil (CPO) and Palm Kernel Oil (PKO). Constraints faced by PT. A is no planned scheduling of machine maintenance. Therefore, it is necessary to design a maintenance strategy in the form of a machine maintenance schedule to overcome the problem, as well as an analysis of the causes of failure of engine components that are often damaged. This problem is solved by using the Reliability Centered Maintenance (RCM) methods in determining repair priorities so that a more optimal treatment plan is obtained. The Pareto diagram is used to determine the most critical machine in the RCM method. The results of the pareto diagram obtained by the screw press machine are the most critical machines. Furthermore, the results of the application of RCM methods obtained components that must be treated regularly (time directed).
... For the two bus system, as shown in Figure 1, an index SI is introduced for stability, which is as follows 34,35 : ...
The expansion of distributed generations (DG) in the distribution networks brings visible technical and economic benefits to the grid. On the other hand, the place and size for DGs in a grid are very important, and optimal selection can decrease voltage profile volatility, system losses, and increase reliability indices especially. The issue of reliability in the distribution system is one of the important parameters in selecting the optimal location of DG. In other words, by considering this parameter, DG location will change in the distribution system and by installing it at this point; the reliability of the network has improved. Therefore, this paper proposes an analytical index to determine the optimal size and siting of DGs in a distribution network. The proposed index has consisted of loss sensitivity factor, voltage stability index, and reliability based factors. To evaluate the efficiency of the proposed method in the previous section, the simulation procedure has been implemented on the IEEE 33 and 69 bus distribution systems. The effectiveness of the suggested index is clarified by using different test systems, and the results have been compared with other proposed methods. The results indicated that the proposed simple index could be acceptable in finding the optimal location and size of DG better than complicated optimization methods.
This paper describes a novel index for ranking of transmission lines for maintenance purpose. Preventive maintenance of transmission lines may be carried out based on prioritization of lines index. The index is based on severity indices, namely (a) thermal limits, (b) voltage limit violation, (c) voltage stability margin and (d) annual outage time. Thus in maintenance prioritization of lines, annual outage time (reliability index) and operational severity have been considered. The index has been obtained by multiplying the operational severity index with the annual outage time to reflect the true picture for the prioritization of transmission lines for maintenance purposes. It is stressed here that the objective of the paper is to provide an assessment of transmission line outage severity so as to provide a ranking list of lines based on peak load for maintenance prioritization. Lines that have higher index can be selected in priority for maintenance from the list. Maintenance activities involve reduction in failure rate and average repair time thereby giving desired availability. Results have been obtained for determining the maintenance priorities of transmission lines using derived index on three standard test systems.
This paper presents a methodology developed to prioritize feeders for receiving investments and analyzing a power utility distribution network. The proposal applies the Analytic Hierarchy Process method to determine which feeders should receive the available resources as a priority. The methodology provides greater assertiveness in decision-making, besides using historical data, the opinion and experience of company specialists. The Plan-Do-Check-Action model assists in verifying improvement interventions, allowing the visualization of the network's stretches with recurring failures, expanding the possibilities for improvement. The correct application of resources is fundamental to the company, as it can guarantee favorable results in feeders' performance, thus improving the company's indicators and the perception that customers have of the utility. The scientific contribution of this paper is the development of a hybrid technique that combines the prioritization method with a model to check its effectiveness, with flexibility, and versatility. In addition, the computational tool developed brought significant time savings for data extraction and analysis, allowing the user to customize the research, defining the periods, types of equipment, and causes of failure easily and quickly.
RAMS is a tool and methodology that combines reliability engineering, availability, maintainability, and safety in a way that is tailored to the system’s goals. A comprehensive view on RAMS’s components and theory behind the underlying mathematical model is not to be found in journal publication. This paper would also discuss several benefits and sustainability of RAMS. Life Cycle Cost (LCC) would also being introduce as a complementary discipline in term of costing that normally regarded parallel to RAMS. There are a series of methods that being utilized at every discipline of the RAMS component such as Fault Tree Analysis (FTA), Failure Mode Effect Critical Analysis (FMECA), Reliability Block Diagram and many more. Some commonly used methods would be highlighted in this paper. RAMS application and implementation will aid asset owners, contractors, and operators in efficiently procuring, developing, and operating their assets. However, further research and analysis is needed in the railway industry to build a viable framework for project and operation implementation using both tools.KeywordsRAMS toolsLCCRailway sustainability
To maintain a multi-component system, different dedicated service teams with different skill sets and tools are often involved. Such a relationship constitutes maintenance team coalition. In most cases, it may not be the best to plan each team's maintenance activities independently as such independent decisions may not achieve the required system-level reliability performance (RP). To balance the reliability and costs of components in achieving a high level of system RP, an efficient method is to assign a failure penalty cost to each maintenance team and then develop their optimal maintenance policy. In this article, the Shapley value is utilized for fair penalty costs allocation to avoid any interest for teams to secede the coalition, whose actual role is to evaluate the criticality level of each component in the context of coalition. Moreover, imperfect inspection and imperfect repair are quite common in practice because of limited resources, technologies and time. To address these practical concerns, a new reliability-centered hybrid preventive maintenance policy is proposed. The optimal inspection interval and age-based replacement interval are determined for each team to minimize the cost rate over an infinite time horizon. Several numerical examples illustrate that the proposed decision-making method is effective in handling such complex maintenance problems involving a coalition of dedicated maintenance teams.
Purpose
Reliability centered maintenance (RCM) is a process used to determine activities to be taken to ensure an asset continues to perform asset's function in asset's present operating context by identifying asset's function, failure modes that could preclude performing asset's intended function, prioritizing failure modes and determining effective preventative maintenance tasks that can be cost effectively and efficiently implemented to reduce the likelihood of a failure.
Design/methodology/approach
A comprehensive survey of literature was undertaken to examine the current industry state of practice. Various industries were examined to better understand applications of RCM within the various industry sectors and determine those industries that RCM has not historically been readily adopted. A case study example of RCM applied to radial gates for water control in open channel canals for water conveyance is presented to demonstrate a civil infrastructure application.
Findings
The results found that RCM has been used since RCM's inception in the airline industry during the 1960s to reduce the cost of maintaining aircrafts. Over the past 40 years, an assortment of industries has begun implementing cost effective preventative maintenance tasks identified during RCM analysis. However, there is a noticeable lack of civil assets being analyzed by RCM, such as water conveyance systems and other civil infrastructure systems vital to the health and well-being of today's societies.
Originality/value
The comprehensive literature review of the current state of practice will provide a better understanding of the various applications of RCM to facilitate RCM's application to other industries, thereby reducing failure due to early identification of maintenance tasks. An example RCM demonstrates the application to a radial gate, used in water conveyance for the drinking water and irrigation sectors, which have not historically used RCM for developing maintenance strategies.
Reliability-centered maintenance (RCM) has recently emerged as a powerful tool to reasonably cut the operation and maintenance cost of power destruction systems, whilst meeting both power quality and reliability requirements. This study introduces a new RMC approach that allocates maintenance budgets based on component criticality and importance. A new diagnostic importance factor, implemented based on the criticality and importance of each component, is introduced as a new index for prioritizing components for maintenance activities and budget allocation. The process of budget allocation is carried out without using any optimization method and just by multiplying the maintenance budget by this newly designed factor. A multi-attribute decision-making technique (MAXIMAX) is considered to find the appropriate weighting coefficient of failure causes to reduce the effect of human dependency in the modeling failure rate of each component. Based on the priority and amount of budget allocated, a reliability-centered maintenance program for the sample distribution system is designed and implemented. The proposed RMC framework was implemented to a part of a distribution network in Iran to highlight its effectiveness and practicality. The obtained results showed an improvement in reliability indexes, which in turn confirms that prioritizing component criticality in budget allocation and maintenance programming enables reaching the reliability goals. Improvement in reliability indexes leads to maintenance cost reduction in future time intervals and efficient management of limited resources. A further comparison analysis with other approaches have shown that the proposed framework outperforms these methods in terms of speed, accuracy and budget allocation.
This paper is aimed at improving the reliability and security of radial distribution system supported by wind turbine generators (WTGs) and superconducting magnetic energy storages (SMESs). For reliability indices assessment, the load-oriented indices including energy not supplied (ENS) and average energy not supplied (AENS) as well as the customers-oriented indices including system average interruption duration index (SAIDI), system average interruption frequency index (SAIFI), customer average interruption duration index (CAIDI), and average service unavailability index (ASUI) are evaluated. Network security index (NSI) is also addressed, which refers to the risk level for current flow in the lines prior reaching to extremis. A multi-objective function is composed and formulated in order to simultaneously minimize ENS, SAIFI, SAIDI, ASUI, and NSI as indices which characterize the performance of distribution system using a hybrid approach based on equilibrium optimizer (EO) along with the loss sensitivity factors. A bi-level optimizer based on the hybrid approach addressing all constraints is applied for simultaneous minimization of reliability and security indices of distribution system. The outer level looks for an optimal sizing and sitting of WTGs and SMESs as well as optimal weighting coefficients whose evaluation is no longer assumed arbitrarily or left to the preferences of the decision maker. The inner level optimizes charging and discharging powers as well as initial state of charge of SMESs. Modeling of feeder's failure rate applying several mathematical functions is considered. The effectiveness of proposed approach is validated on the IEEE 33-bus test system considering commercial, industrial, residential, and mixed time-varying voltage-dependent load models. The performance of the distribution system is also checked as regards the energy loss in feeders, the bus voltage deviation from rated value as well as the voltage stability of the system. For validating the effectiveness of the EO algorithm, the obtained results using the EO algorithm are compared with those predicted by particle swarm optimization (PSO) and genetic algorithm (GA). Moreover, the obtained results display that the bi-level optimization can successfully achieve satisfactory improvement of the reliability and security indices of the distribution system.
Online reliability assessment is not only crucial for the safe and stable operation of energy systems but also meaningful for guaranteeing satisfactory economic competitiveness. Due to the system reliability can be determined by the failure-rate and operation time, the central in online reliability assessment of energy systems is the evaluation of failure-rate. Further, it can be seen that the deviations of actual responses of process variables from their expectations reflect the effect of total disturbance, and large deviations usually denote the existence of the degradation of system reliability. Hence, the failure-rate can be evaluated based on the estimation of total disturbance and its differentiation. In this paper, a high-order extended state observer (HO-ESO) is proposed for the nonlinear dissipative system representing typical energy system dynamics, which provides globally bounded observations for not only system state-variables but also the total disturbance and its differentiation. Then, the evaluations of both the failure-rate and the system reliability can be given online based on the estimation provided by the HO-ESO. Further, this HO-ESO-based online reliability assessment method is applied to the health monitoring of pressurized water reactor (PWR). After checking the dissipation condition of PWR, the HO-ESO of PWR is designed, and the simulation results show the feasibility and effectiveness.
Ссылка для цитирования: Анализ потерь электроэнергии в системе электроснабжения обогатительной фабрики / Р.В. Клюев, В.И. Голик, И.И. Босиков, О.А. Гаврина // Известия Томского политехнического университета. Инжиниринг георесурсов. – 2021. – Т. 332. – № 10. – С. 7–16. Актуальность работы обусловлена необходимостью комплексного исследования системы электроснабжения обогатительных фабрик. Для этого следует разработать эффективную методику расчета потерь электроэнергии по отдельным технологическим механизмам и фабрике в целом, что даст возможность существенно сократить энергетическую составляющую затрат в ходе выпуска продукции. Цель: разработать методику определения потерь электроэнергии по отдельным технологическим механизмам в различных режимах работы, которая может быть использована на аналогичных предприятиях. Объекты: горно-обогатительные фабрики, которые характеризуются сложностью определения энергетических характеристик технологического оборудования. Методы: совокупность детерминированных и вероятностно-статистических методов определения потерь электроэнергии. Детерминированные методы включают расчет максимальных потерь, средних нагрузок, графического интегрирования, среднеквадратичного тока. В свою очередь, вероятностно-статистические основаны на исследовании статистических характеристик и применении статистических выборок схем сети. Результаты. На основании экспериментальных исследований разработана методика определения потерь электроэнергии в элементах системы электроснабжения обогатительной фабрики в номинальном и в эксплуатационном режиме. Установлено, что отношение коэффициентов потерь в номинальном и эксплуатационном режимах работы, определяющее степень использования пропускной способности кабельной сети 6 кВ, находится в пределах 1,02–2,57. В среднем кабельная сеть 6 кВ недогружена на 25–30 %. Фактические потери электроэнергии в кабельной сети 6 кВ оказались меньше номинальных и составляют менее 1 % от общей потребляемой электроэнергии, следовательно, проведение каких-либо мероприятий для уменьшения потерь электроэнергии нецелесообразно. Средневзвешенный коэффициент мощности по обогатительной фабрике равен 0,82, поэтому может оказаться целесообразным проведение мероприятий по компенсации реактивной мощности. Расчет параметров компенсирующих устройств и выбор места их установки предусмотрены планом работ на будущий период.
El objetivo del presente trabajo consiste en realizar un análisis de la situación actual del mantenimiento centrado en la confiabilidad (RCM) en la industria, así como mostrar en forma detallada una metodología para su aplicación. Para complementar dicho objetivo se realizó un análisis bibliográfico, para lo cual se consultaron las principales bases de datos que contienen literatura especializada sobre esta temática, además se realizó un estudio histórico lógico del surgimiento y evolución de este tipo de gestión de mantenimiento. Los resultados, exponen las bases teóricas y fundamentan la gestión del mantenimiento centrada en la confiabilidad con respecto a los aspectos actuales, tradiciones y particularidades de la gestión eficiente del mantenimiento. Se detalló, además el procedimiento para la elaboración del análisis de modos y efectos de fallas (AMEF), mostrando que tanto el procedimiento RCM como la metodología AMEF son sistemáticos y parten de una secuencia lógica, orientada a priorizar los equipos y reducir los costos de la actividad de mantenimiento en la medida que se crea una confiabilidad operacional. Palabras clave: Confiabilidad, RCM, Mantenimiento, Gestión.
In today's society, due to the importance of electricity and its vital role in the daily lives of citizens, problems related to shutdown management and reduce the shutdown of subscribers' electricity is one of the important concerns of managers in the field of the electricity industry. On the other hand, it is a key parameter in evaluating the performance of the country's electricity industry, especially electricity distribution companies. The aim of this study is to the scheduling of preventive maintenance on a set of feeders in the Electricity Distribution Company of Ilam Province according to its real-world conditions. In this regard, for the first time, mathematical programming is proposed for the problem. Then, two heuristic algorithms to achieve a good solution in a reasonable time as well as upper and lower bounds are provided. Using a real example, the results of the proposed algorithms were validated. The results of heuristic algorithms were very appropriate and practical due to GAMS's inability to solve large-scale problems. Given that the company currently does not have a specific model for the optimal allocation of feeders, the results of this research can be used to reduce the amount of undistributed energy in the network and subsequently increase subscriber satisfaction.
Microgrid(MGs) formation of distribution network with high penetration of distributed energy resources(DERs) affects not only the improvement of power supply reliability, but also the utilization efficiency of renewable resources. Here a fast partition method constructing MGs is proposed by combining depth search with a modified imperial competition algorithm (MICA). For the purpose of decreasing search space as well as assuring DERs maximum utilization, Candidate Island is investigated to determine the maximum reachability boundary of MGs in island mode. When in the dilemma of constructing Isolated Island (i.e., MGs with single DERs) or Jointed Island (i.e., MGs with multiple DERs), the reliability calculation method for MGs with multiple DERs and multisystem is available here. Also, the principle of MGs construction is presented by considering load grade, voltage loss and reliability. On this basis, MICA is employed to carry out the construction of MGs by competing for the intersection among multiple MGs and evolve the optimal island with high reliability accordingly. Furthermore, the parallel strategy improving the efficiency of island partition is given to guarantee an immediate response in abnormal, emergent and fault states. IEEE RBTS Bus 6 with additional DERs and several modified distribution networks with multiple DERs verified the effectiveness of the proposed method.
Reliability-centered maintenance (RCM) is a well-established method for preventive maintenance planning. This paper focuses on the optimization of a maintenance plan for an HVAC (heating, ventilation and air conditioning) system located on high-speed trains. The first steps of the RCM procedure help in identifying the most critical items of the system in terms of safety and availability by means of a failure modes and effects analysis. Then, RMC proposes the optimal maintenance tasks for each item making up the system. However, the decision-making diagram that leads to the maintenance choice is extremely generic, with a consequent high subjectivity in the task selection. This paper proposes a new fuzzy-based decision-making diagram to minimize the subjectivity of the task choice and preserve the cost-efficiency of the procedure. It uses a case from the railway industry to illustrate the suggested approach, but the procedure could be easily applied to different industrial and technological fields. The results of the proposed fuzzy approach highlight the importance of an accurate diagnostics (with an overall 86% of the task as diagnostic-based maintenance) and condition monitoring strategy (covering 54% of the tasks) to optimize the maintenance plan and to minimize the system availability. The findings show that the framework strongly mitigates the issues related to the classical RCM procedure, notably the high subjectivity of experts. It lays the groundwork for a general fuzzy-based reliability-centered maintenance method.
Most maintenance strategies serving for the practical applications are formulated based on the single maintenance objective and do not consider the physical layout of compressor units in the complex pipeline networks and the actual maintenance demands, resulting in the over-maintenance or under-maintenance. The effective maintenance strategies for compressor units improve the unit reliability, economy, and maintenance efficiency. This work establishes a multi-level maintenance scheduling model composing of unit life prediction, unit-level maintenance decision, and system-level maintenance scheduling to guide the maintenance planning with cost and availability as the evaluation objectives. The maintenance strategies are developed by considering the series-parallel layout of compressor units, actual maintenance demands, and maintenance capability. The effectiveness of the proposed model is verified through 31 compressor unit networks in the Chinese west-east gas pipeline under the strategies of separating maintenance, combining maintenance, single maintenance team, and multiple maintenance teams, and compared it with the traditional methods. Compared with the traditional individual and simultaneous maintenance modes, the proposed method based on the optimal time window can reduce the maintenance cost by at least 27.7% and 25.1%, respectively. The weight factors and reliability have a great influence on the cost increase rate and unit availability. The multi-objective maintenance scheduling can improve the unit availability by 1.6% compared with the single availability optimization objective, and the corresponding maintenance cost rate is only increased by 0.68%. For the complex compressor unit networks, it is a better choice to consider the multi-objective maintenance planning under the single maintenance team. The model can improve the anti-risk ability of compressor units in long-distance natural gas networks and put forward maintenance suggestions from the perspective of safety, economy, and reliability.
The energy power supply infrastructure of a hospital, to function correctly, needs to be well maintained to ensure its reliability and, by consequence, the maximum integrated availability. In this paper, the authors propose the use of Petri Nets to help the improvement of the electric power system reliability, having as a case study a big European Hospital. The purpose of the research is to identify and analyse the potential failures of the system and to suggest solutions to improve the operations and maintenance to maximise the availability and reliability of those assets through possible and objective answers. It was necessary to develop a diagnosis and planning methodology to assess the reliability of several components of the energy power supply system. It is dynamic modelling based on a block diagram of the system and transposed to representation by Petri Nets. The analysis and the simulation of the discrete events of the system, as well as the visualisation of the process functioning and the communications inside, was made. Additionally, they were referred to other approaches, like the Fuzzy Petri Nets and Stochastic Petri Nets, as well as a future balance about its application in a situation like the analysed in this paper
The article presents the results of developing a program that allows determining the reliability indicators of individual elements of the electric power system. Distribution electric power systems perform an important function in the overall energy structure. That is, the reliable operation of individual elements of the power system depends on the uninterrupted transmission of electricity over air lines to end users. An example of calculation is given for Sevkavkazenergo IDGC of the North Caucasus. The summary table shows the values of reliability indicators of the elements of the energy system under study, distributed over the years and used for reliability analysis and forecasting. Using the data from this table, regression models can be built, and the adequacy and reliability of the forecast are estimated based on known methods of factor-regression analysis. To do this, it is necessary to develop appropriate programs that meet the tasks set. It was found that the distribution of the failure rate among them is not the same, so about 20% of the lines on average were disconnected 2–3 times a year for different reasons and for different durations, including the time when the automation was switched off. More than 30% of air lines were disconnected no more than 2–3 times during the entire study period of 2011–2017.
Reliability Centered maintenance (RCM) procedure was suggested for HVAC system of a recently established forensic laboratory at ICCBS, Karachi. The system comprises of three major components; 1.) Air Handling Unit 2.) Condensing Unit 3.) Thermostat Box. RCM decision and information worksheet along with detailed preventive maintenance plan was proposed for the HVAC system. A trained HVAC maintenance team is needed to implement RCM strategy to prevent early failures and ensure 24/7 availability of the HVAC System.
Preventive maintenance is recognized nowadays as a way of addressing adequately industrial systems or assets health management problem. To this end, approaches such as prognostics and health management (PHM) are being developed by researchers to support making predictive maintenance decisions by relaying on quantitative indicators such as remaining useful life (RUL); that is basically the projected time to failure of a given system. In general, an industrial system is composed of many components which failure may lead to the failure of the system; so that identification of such components which are referred to as critical components, constitute therefore an important stake. The process of identifying such components is based on many methods encountered in the literature among which experience feedback is drawing more and more attention of researchers because of, among other reasons, the fact that companies dispose nowadays of huge amount of functioning data of their systems. The aim of this paper is to develop a methodology based on experience feedback to identify critical components of a given industrial system. The proposed methodology will be applied to a real world case in broadcast industry to show its feasibility.
Identification of critical components and their prioritization for implementation of maintenance is an important task in industry. It is also one of the essential step of reliability-centered maintenance. In this paper, an attempt made is being made to find out the key factors associated with the criticality of components. Five major criteria affecting criticality of components i.e. cost, functional dependency, complexity, maintainability, and safety impact were proposed for criticality analysis. In addition, to identify the critical components a hierarchical network is proposed based on analytic network process. The proposed methodology evaluated with a case study on CNC lathe machine. This study can provide a realistic solution to decision-making problems for maintenance planning in prioritizing the critical component for reliability-centered maintenance.
This paper presents a new algorithm for systematic coordinated maintenance of the elements of a transmission bay. The proposed method implements a knowledge-based Markov model to introduce a non-periodic model for maintenance scheduling. The mode based maintenance scheduling is implemented in this work which is preferred to element-based one, due to the practical issues. To investigate the effects of maintenance on system’s reliability, the network is modeled through its second order equivalent cut-set. Contrary to previous works which consider each element separately; the presented approach tries to evaluate the optimum maintenance plan for entire elements of a bay by considering all elements of a bay together and coordinating the maintenance plan of each element. In this paper, various types of maintenance plan are considered and the optimum plan for each element is evaluated using Genetic algorithm. Finally, the practicality of the proposed method is investigated using a typical transmission bay.
Engine performance varies significantly due to the variations in weather conditions in different regions. So, in order to optimize the performance and fuel consumption, engines should be calibrated according to the weather conditions in which they operate. In this paper the effects of the air conditions (such as pressure and temperature) on the power and fuel consumption of the SI engine are modeled. First a comprehensive one-dimensional model of the real engine is constructed in GT POWER®, and validated with experimental data from actual engine. Next, using this model, a set of experiments is carried out by varying pressure, temperature, and humidity of the incoming air, and engine speed. The measuring outputs are the power and BSFC of the engine. Then, two mathematical models are developed using MLP Neural Networks and also regression technique to estimate the outputs in terms of the inputs. At last, the estimation ability of the models is shown by a set of new experiments. These models could be used in engine calibration and shift the process from a near blind one to the one in which prior information have a significant role.
In this paper, we present a new reliability model and a unique condition-based maintenance model for complex systems with dependent components subject to respective degradation processes, and the dependence among components is established through environmental factors. Common environmental factors, such as temperature, can create the dependence in failure times of different degrading components in a complex system. The system under study consists of one dominant/independent component and n statistically dependent components that are all subject to degradation. We consider two aspects that link the degradation processes and environmental factors: the degradation of dominant/independent component is not affected by the state of other components, but may influence environmental factors, such as temperature; and the n dependent components degrade over time and their degradation rates are impacted by the environmental factors. Based on the thermodynamic study of the relationship between degradation and environmental temperature, we develop a reliability model to mathematically account for the dependence in multiple components for such a system. Considering the unique dependent relationship among components, a novel condition-based maintenance model is developed to minimize the long run expected cost rate. A numerical example is studied to demonstrate our models, and sensitivity analysis is conducted to test the impact of parameters on the models.
In this work, the airflow behavior and particle transport and deposition in different breathing conditions such as light breathing condition (15 L/min), normal breathing condition (30 L/min) and heavy breathing condition (60 L/min) are investigated. The realistic geometry data was reconstructed from CT-scan images of the human airways with 0.5 mm thickness of slices. The CT-scan images (DICOM files) are imported in the 3D-DOCTOR software and all slices were segmented. Then, the output has been imported in CATIA-V5 software. Finally, face, volume, mesh and extension tubes at inlet and outlets were created and then imported into ANSYS FLUENT 15. The Lagrangian approach is used to evaluating the transport and deposition of inhaled micro-particles. The presented results showed that for dp = 5 μm and 10μm, when flow rate and for dp = 1 μm, when flow rate , the particle deposition fraction have maximum amount. For flow rate and , the maximum deposition occurs in the zone number 1 and for flow rate occurs in the zone number 4. Also, the maximum pressure distribution happens when flow rate which would be acceptable. According to the results, the particles tended to go to the right branch and the minimum number of particles crossed the zone numbers 6 and 11.
Today’s electricity distribution systems operate in a liberalized market. These systems should therefore be able to provide electricity to customers with a high degree of reliability and be cost-effective for suppliers. RCM (Reliability Centred Maintenance) was invented by the aircraft industry in the 1960s, to organize the increasing need for maintenance for reducing costs without reducing b safety. Today RCM-methods invented by ALADON [1] are seen as very complex and are not fully accepted by the Algerian power industry. The extensive need of human and capital resources in the introduction phase is also a negative factor that could be one of the reasons of why RCM methods are not used in our branch. This article provides a discussion of the two primary objectives of RCM: to ensure safety through preventive maintenance actions, and, when safety is not a concern, preserve functionality in the most economical manner. For the power distribution systems facilities, the mission should be considered at the same level as safety.
Maintenance has gained in importance as a support function for ensuring equipment availability, quality products, on-time deliveries, and plant safety. Cost-effectiveness and accuracy are two basic criteria for good maintenance. Reducing maintenance cost can increase enterprise profit, while accurate maintenance action can sustain continuous and reliable operation of equipment. As instrumentation and information systems become cheaper and more reliable, condition-based maintenance becomes an important tool for running a plant or a factory. This paper presents a novel condition-based maintenance system that uses reliability-centered maintenance mechanism to optimize maintenance cost, and employs data fusion strategy for improving condition monitoring, health assessment, and prognostics. The proposed system is demonstrated by way of reasoning and case studies. The results show that optimized maintenance performance can be obtained with good generality.
Although reliability-centered maintenance (RCM) has proven its noticeable merits in many industries, has not been yet furnished with efficient analytical methods in the power engineering context. The first of this two-paper set presents a practical framework by which the RCM procedure can be implemented in power distribution systems. The proposed algorithm consists of three main stages. The prerequisites of the analysis are outlined in the first stage. In the second stage, an approach is developed to identify the network's critical components, from the reliability point of view. Having practically modeled the components' failure rates, an efficient cost/benefit evaluation approach is then proposed to distinguish a variety of maintenance plans. The optimal set of maintenance strategies is next adopted for implementation. The algorithm is terminated in the third stage by recording both technical and economical outcomes for tuning the forward maintenance activities. The proposed methodology, although tailored to distribution networks, is generic enough to be applied to other power system areas. In the companion paper, the proposed methodology is examined by application to the Birka distribution system of Stockholm City, Sweden, and more practical aspects are discussed.
Confronted with the power system restructuring trend reforming the past-regulated power systems, the need for a narrower insight on the costly maintenance strategies seems imperative. It falls within the realm of reliability centered maintenance to enhance the cost effectiveness of power distribution maintenance policies. From a practical point of view, this paper devises a novel approach on the basis of the analytical hierarchical process (AHP) accompanied by fuzzy sets theory to determine the most critical component types of distribution power systems to be prioritized in maintenance scheduling. In the presence of many qualitative and quantitative attributes, fuzzy sets can effectively help to deal with the existent uncertainty and judgment vagueness. As demonstrated in a practical case study, the proposed fuzzy AHP method introduces its applicability and efficiency in the asset management procedure.
This research work presents a new approach to prioritize distribution maintenance activities based on system reliability and cost-effectiveness. The objective of this approach is to minimize the weighted average system reliability index (WASRI) by ranking maintenance tasks based on their marginal benefit-to-cost ratios, where the benefit is defined as improvement in WASRI. Estimations of WASRI improvement are obtained by utilizing the linear relationship between the benefit obtained from a maintenance task and the change of failure rate of the maintained component.
This paper proposes a method for comparing the effect of different maintenance strategies on system reliability and cost. This method relates reliability theory with the experience gained from statistics and practical knowledge of component failures and maintenance measures. The approach has been applied to rural and urban distribution systems. In particular, a functional relationship between failure rate and maintenance measures has been developed for a cable component. The results show the value of using a systematic quantitative approach for investigating the effect of different maintenance strategies.
This paper describes a new method of optimization maintenance selection for the power distribution system equipment that is based on the cumulative long-term risk caused by failure of each piece of equipment. The method is developed from RCM principles attempting to relate more closely the impact of maintenance to the cost and reliability of the system. The aim is to see with quantitative methods the effect on a component level of preventive maintenance on system reliability results. The method is illustrated on a sample of electricity distribution network, located in RELIZANE northwest of Algeria.
This paper deals with the process of criticality analysis in overhead power lines, as a tool to improve maintenance, felling & pruning programs. Felling & pruning activities are tasks that utility companies must accomplish to respect the servitudes of the overhead lines, concerned with distances to vegetation, buildings, infrastructures and other networks crossings. Conceptually, these power lines servitudes can be considered as failure modes of the maintainable items under our analysis (power line spans), and the criticality analysis methodology developed, will therefore help to optimize actions to avoid these as other failure modes of the line maintainable items. The approach is interesting, but another relevant contribution of the paper is the process followed for the automation of the analysis. Automation is possible by utilizing existing companies IT systems and databases. The paper explains how to use data located in Enterprise Assets Management Systems, GIS and Dispatching systems for a fast, reliable, objective and dynamic criticality analysis. Promising results are included and also discussions about how this technique may result in important implications for this type of businesses.
This study presents a lifetime efficiency index model for substation equipment and proposes an appropriate method for the optimal maintenance of substation equipment. Along the substation equipment lifetime, due to ageing and daily operations, the failure rate increases gradually. So it is needed to do a maintenance strategy for the aim of reduction in the failure rate and improvement in the reliability of equipment. The maintenance strategy for substation equipment typically consists of preventive and corrective maintenance. By the lifetime efficiency index, one can analyse the lifetime of the equipment under the conditions of with and without maintenance. In this study, the failure rate of the equipment is modelled by the appropriate Weibull distribution. Maintenance can keep equipment in normal condition, but it incurs cost. The maintenance strategy should be optimised for the minimum maintenance cost under the required reliability condition. In order to solve this objective problem, a cuckoo optimisation algorithm (COA) is used and results are evaluated. The results based on an example show that the proposed COA was indeed capable of obtaining higher quality solutions than other methods for the optimal maintenance.
This paper investigates numerically the problem of unsteady magnetohydrodynamic nanofluid flow and heat transfer between parallel plates due to the normal motion of the porous upper plate. The governing equations are solved via the fourth-order Runge-Kutta method. Different kind of nanoparticles is examined. The effects of kind of nanoparticle, nanofluid volume fraction, expansion ratio, Hartmann number, Reynolds number on velocity and temperature profiles are considered. Also effect of different types of nanoparticles is examined. Results indicate that velocity decreases with increase of Hartmann number due to effect of Lorentz forces. Rate of heat transfer increase with increase of nanofluid volume fraction, Hartmann number and Reynolds number but it decreases with increase of expansion ratio. Also it can be found that choosing copper as a nanoparticle leads to highest enhancement.
Despite their importance for the proper operation of both care and non-care services, there are no models in the literature analysing the choice of the most suitable maintenance strategy to be applied in electric power distribution systems in Health Care Organizations. This paper presents an innovative multicriteria which contributes to ensuring the best quality of care for the patient. The model integrates the Measuring Attractiveness by a Categorical Based Evaluation Technique approach with Markov chains to obtain the expected mean availability for different electric power distribution systems. The result is a full classification of the combination of maintenance policies and actions (redundancy), to be applied in power distribution systems. The model gives, as the most suitable maintenance strategy, a combination of corrective, preventive and predictive maintenance (thermal analysis). It is the first model produced and applied to a variety of electric power distribution systems responsible for supplying electrical energy to critical areas of the Health Care Organizations, such as operating theatres, intensive care units, paediatrics, general lighting and other specific areas. The result obtained is compared with the maintenance policy currently used by the organization, and a plan for the implantation of the alternative given for the model is produced.
Maintenance scheduling and asset management practices play an important role in power systems, specifically in power generating plants. This paper presents a novel risk-based framework for a criticality assessment of plant components as a means to conduct more focused maintenance activities. Critical components in power plants that influence overall system performance are identified by quantifying their failure impact on system reliability, electric safety, cost, and the environment. Prioritization of plant components according to the proposed risk-based method ensures that the most effective and techno-economic investment decisions are implemented. This, in turn, helps to initiate modern maintenance approaches, such as reliability-centered maintenance (RCM). The proposed method is applied to a real combined cycle power plant (CCPP) in Iran, composed of two gas turbine power plants (GTPP) and one steam turbine power plant (STPP). The results demonstrate the practicality and applicability of the presented approach in real world practices.
There are many models in the literature that have been proposed in the last decades aimed at assessing the reliability, availability and maintainability (RAM) of safety equipment, many of them with a focus on their use to assess the risk level of a technological system or to search for appropriate design and/or surveillance and maintenance policies in order to assure that an optimum level of RAM of safety systems is kept during all the plant operational life. This paper proposes a new approach for RAM modelling that accounts for equipment ageing and maintenance and testing effectiveness of equipment consisting of multiple items in an integrated manner. This model is then used to perform the simultaneous optimization of testing and maintenance for ageing equipment consisting of multiple items. An example of application is provided, which considers a simplified High Pressure Injection System (HPIS) of a typical Power Water Reactor (PWR). Basically, this system consists of motor driven pumps (MDP) and motor operated valves (MOV), where both types of components consists of two items each. These components present different failure and cause modes and behaviours, and they also undertake complex test and maintenance activities depending on the item involved. The results of the example of application demonstrate that the optimization algorithm provide the best solutions when the optimization problem is formulated and solved considering full flexibility in the implementation of testing and maintenance activities taking part of such an integrated RAM model.
In the present investigation, detailed two-phase flow modeling of airflow, transport and deposition of micro-particles (1-10µm) in a realistic tracheobronchial airway geometry based on CT scan images under various breathing conditions (i.e. 10-60l/min) was considered. Lagrangian particle tracking has been used to investigate the particle deposition patterns in a model comprising mouth up to generation G6 of tracheobronchial airways. The results demonstrated that during all breathing patterns, the maximum velocity change occurred in the narrow throat region (Larynx). Due to implementing a realistic geometry for simulations, many irregularities and bending deflections exist in the airways model. Thereby, at higher inhalation rates, these areas are prone to vortical effects which tend to entrap the inhaled particles. According to the results, deposition fraction has a direct relationship with particle aerodynamic diameter (for dp=1-10µm). Enhancing inhalation flow rate and particle size will largely increase the inertial force and consequently, more particle deposition is evident suggesting that inertial impaction is the dominant deposition mechanism in tracheobronchial airways.
Abstract This paper presents an algorithm for deciding preferences in maintenance activities for feeder sections of distribution systems. A component importance measure, known as diagnostic importance factor (DIF), has been used for this purpose. A methodology has been developed to compute a newly framed weighted cumulative diagnostic importance factor (WCDIF) for each feeder section which represents quantitatively relative significance for prioritization of maintenance activities. The developed methodology includes the effect of distributed generations (DG) and loads. It has been implemented on two sample distribution systems and ranking lists of feeder sections for maintenance activities have been obtained.
This paper proposes a new methodology for the evaluation of reliability in radial distribution networks through the identification of new investments in this kind of networks, in order to reduce the repair time and the failure rate, which leads to a reduction of the forced outage rate and, consequently, to an increase of reliability. The novelty of this research work consists in proposing an ac optimization model based on mixed-integer nonlinear programming that is developed considering the Pareto front technique, in order to achieve a reduction of repair times and of failure rates of the distribution network components, while minimizing the costs of that reduction, the power losses cost, the cost of the optimal capacitor location and size, and the maximization of reliability, which is in the form of minimization of nonsupplied energy cost. In order to estimate the outage parameters, a fuzzy set approach is used. The optimization model considers the distribution network technical constraints. A case study using a 33-bus distribution network is presented to illustrate the application of the proposed methodology.
In this paper, a novel methodology is presented to evaluate the micro-grids reliability concerning the dynamic thermal aging failure of transformers. The widespread presence of distributed generation (DG) units reduces the loading passing through the distribution transformers and consequently improves the dynamic thermal failures. The system reliability is investigated for various penetrations of different scenarios from the view of DG technologies. The introduced method is applied to a realistic distribution system comprising different distribution transformers in Iran. The sensitivity analysis corresponding to adequacy indices such as expected energy not-supplied (EENS) based on DG penetrations is performed. By the use of the novel methodology proposed, it is possible to recognize how different DG technologies and penetrations can impact on the system reliability. The results demonstrate that the diesel generators and hybrid systems including diesel generators, photovoltaic units, and wind turbines are the most promising DG technologies to improve the transformer failures and the reliability of micro-grids compared with renewable DG units.
The goal of this study is to propose a reliability centered predictive maintenance scheme for a complex structure Inertial Navigation System (INS) with several redundant components. GO Methodology is applied to build the INS reliability analysis model—GO chart. Components Remaining Useful Life (RUL) and system reliability are updated dynamically based on the combination of components lifetime distribution function, stress samples, and the system GO chart. Considering the redundant design in INS, maintenance time is based not only on components RUL, but also (and mainly) on the timing of when system reliability fails to meet the set threshold. The definition of components maintenance priority balances three factors: components importance to system, risk degree, and detection difficulty. Maintenance Priority Number (MPN) is introduced, which may provide quantitative maintenance priority results for all components. A maintenance unit time cost model is built based on components MPN, components RUL predictive model and maintenance intervals for the optimization of maintenance scope. The proposed scheme can be applied to serve as the reference for INS maintenance. Finally, three numerical examples prove the proposed predictive maintenance scheme is feasible and effective.
The purpose of the this paper is to make decision of the maintenance priority of power distribution system using Time-Varying Failure Rate(TVFR) with interruption cost. This paper emphasizes the practical use of the reliability indices and interruption cost. To make a decision of maintenance priority on power distribution system equipment, the quantification of the reliability level should be represented as a cost. In this paper, the TVFR of power distribution system equipment applied in this paper utilizes analytic method to use the historical data of KEPCO. From this result, the sensitivity analysis on TVFR of equipment was done for the priority, which represents that high priority of the equipment has more effect on system reliability, such as SAIDI or SAIFI, than other equipment. By this priority, the investment plan is established. In this result, customer interruption cost(CIC) could be extracted, and CIC is used as weighting factor to consider a importance of customer. After that, the result calculated the proposal method in this paper is compared with other priority method, such as lifetime, failure rate or only sensitivity.
(Paper available on: http://www.sciencedirect.com/science/article/pii/S0925753513002531)
Continuous type production and discrete type manufacturing systems face challenges in optimizing the maintenance related costs. The risk based maintenance approach has been carried out within the continuous type production systems to classify equipment in production and process facilities based on the risk of failure that can cause financial, societal and environmental challenges to the asset owner. At the same time the term ‘machine classification’ (MC) has been used within the discrete type manufacturing systems to classify machines based on the influence on; production process to continue, delay in deliveries, product quality as well as personnel, process, societal and environmental safety. Initially, this paper discusses the role of the MC in mitigating health, safety and environmental challenges. Then, it derives an empirical formula performing classification of machines. The derivation has been performed by carrying out a case study in three manufacturing companies and utilizing the three different MC models employed by them. Finally, the manuscript verifies the empirical formula with an arbitrarily selected manufacturing organization.
Reliability centered maintenance (RCM) is a well-established analysis method for preventive maintenance planning. As its name indicates, reliability is the main point of reference for the planning, but consequences of failures are also assessed. However, uncertainties and risk are to a limited extent addressed by the RCM method, and in this paper we suggest an extension of the RCM to reliability and risk centered maintenance (RRCM) by also considering risk as the reference for the analysis in addition to reliability. A broad perspective on risk is adopted where uncertainties are the main component of risk in addition to possible events and associated consequences. A case from the offshore oil and gas industry is presented to illustrate and discuss the suggested approach.
This volume evaluates the different concepts, models, and techniques used to measure the reliability of power systems in both planning and operating phases. Applications of the techniques presented in the text are illustrated in numerical examples and diagrams. Areas discussed include basic probability plus frequency and duration methods for determining generating capacity, interconnected systems, operating reserve, composite generation and transmission systems, and plant and station availability.
This paper presents an analytical technique based on the device of stages for distribution system reliability evaluation. This technique models the aging of equipment in evaluating the reliability indices. The three main indices evaluated are failure rate, outage time, and average annual outage time for each load point. An additional set of indices (performance indices) is also calculated using these three basic indices and the number of customers/loads connected at each load point in the system. The most common performance indices are SAIFI, SAIDI, CAIDI, and ASAI. A computer program has been developed to implement this method on a DEC VAX-8800 computer. Finally, system studies are performed to evaluate the basic and performance reliability indices using various models.
Maintenance management of industrial equipment is an important but still relatively neglected business function. This paper identifies and discusses the most important elements of its decision making environment. As such the paper contributes to the structuring of the maintenance management area and it provides a frame of reference for further research in maintenance policy optimization. The paper starts with a brief description of maintenance management in a business context. In the remainder of the paper three parts may be distinguished. The first addresses the system design aspects of maintenance management in the broader operations management environment, the second examines the most important issues in maintenance decision making and the last part reviews the managerial tools available for decision making in this area. An extensive list of references is provided.
Maintenance operations have a direct influence on production performance in manufacturing systems. Short-term production analysis is imperative to enable manufacturing operations to optimally respond to dynamic changes in the system behavior. However, most of the conventional decision support systems for production and maintenance focus on long-term statistic analysis, which is usually not applicable to a short-term period. Maintenance task prioritization is crucial and important for short-term analysis to reduce unnecessary or improper maintenance activities, especially when availability of maintenance resources is limited. The existing methods for maintenance priority assignment are often through heuristic methods or experience, which could cause unscheduled downtime and production losses. In this paper, a short-term decision support system for maintenance task prioritization based on the system operating conditions is introduced. The impact factor for priority assignment is obtained theoretically. A case study based on the simulation of an automotive assembly line illustrates that the proposed short-term system improves the system performance with a lower cost than the long-term method.
Average weighting coefficients of WI index at second level
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Pintelon LM, Gelders LF. Maintenance management decision making. Eur J
Fig. 5. Average weighting coefficients of WI index at second level.
Methods to consider customer interruption costs in power system analysis
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Critical components identification based on experience feedback data in the framework of PHM
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