Reliability Models Of Components Research Articles

Situation modeling and evaluation for complex systems: A case study of satellite attitude control system

Situation modeling and evaluation for complex systems: A case study of satellite attitude control system

Operational Reliability of Integrated Energy Systems Considering Gas Flow Dynamics and Demand-Side Flexibilities

The interdependency among the electricity, gas, heat, and cooling energy systems is ever-increasing. The flexible energy utilization patterns on the demand side and gas flow dynamics in the transmission system bring both opportunities and challenges to the reliable operation of integrated energy systems (IES). For example, if the electricity supply is interrupted, the gas system can ramp up the gas supply to the gas-fired units using linepacks. By this means, the reliability of the electricity system at this moment can be improved, while the gas system's capability of withstanding future risks may be undermined. Therefore, the operational reliability between different energy systems and time periods should be carefully balanced. This paper proposes an operational reliability evaluation framework for the IES considering flexibilities from both the demand side and transmission system. Firstly, the flexibilities of end-users and linepacks are explored based on the Energy Hub and gas flow dynamics models. Then, the reliability models of IES components are developed using the discretized-time Markov process to characterize the temporal state evolution in the operational horizon. A look-ahead contingency management scheme of the IES is then proposed to minimize the electricity and gas load curtailments. Taking account of all the possible system states, the operational reliabilities of the IES are evaluated using the time-sequential Monte Carlo simulation. Finally, the proposed method is validated by using the IEEE Reliability Test System and the practical Belgium gas transmission system.

A semi-Markovian approach to evaluate the availability of low voltage direct current systems with integrated battery storage

A semi-Markovian approach to evaluate the availability of low voltage direct current systems with integrated battery storage

Reliability Evaluation Method of Multi-Voltage Levels Distribution System Considering the Influence of Sense-Control Terminal Faults

With the existing reliability evaluation methods, it is difficult to realize the overall evaluation of multi-voltage levels distribution systems, and sense-control terminal faults are not considered in the process of reliability evaluation. Therefore, a reliability evaluation method for multi-voltage levels distribution networks considering the influence of the fault of the sensing and control terminal is proposed. Firstly, based on the component reliability model, system state selection method, and reliability index, a reliability evaluation method for distribution networks considering sense-control terminal faults has been proposed. Secondly, the features of a multi-voltage levels distribution network are analyzed. The sequential Monte Carlo simulation method and the failure mode effects analysis method are combined, and a collaborative evaluation method for power supply reliability of multi-voltage levels distribution systems is proposed. Eventually, the effectiveness of the proposed method is proved by an example comparison, and the impact of the terminal fault on the reliability of distribution network is analyzed. The reliability evaluation results can provide technical support for the planning of the distribution network.

A DNN-based reliability evaluation method for multi-state series-parallel systems considering semi-Markov process

A DNN-based reliability evaluation method for multi-state series-parallel systems considering semi-Markov process

Improved maintenance strategy for the wind turbine system under operating and climatic conditions

This paper studies and proposes a novel joint policy of production, imperfect and priority maintenance for a wind turbine system connected to battery storage and supply grid. The failure rate of wind farm is closely related to production rate and working time. The objective of this paper is to establish an economical energy production and imperfect maintenance plans minimizing the various costs incurred, taking into account the electricity demand variation, uncertainty of wind velocity, and the service level. The proposed maintenance strategy based on the priority and selective maintenance actions aims to choose the priority components for maintenance, while minimizing the total maintenance cost and ensuring a minimum reliability level for the wind turbine system. To achieve the latter goal, we formulate the reliability model of the wind turbine components by considering the influence of operating and environmental conditions. Numerical examples and sensitivity analyzes are presented to illustrate the significance and the effectiveness of the proposed methodology.

Anticipating water distribution service outages from increasing temperatures

With projected temperature increases and extreme events due to climate change for many regions of the world, characterizing the impacts of these emerging hazards on water distribution systems is necessary to identify and prioritize adaptation strategies for ensuring reliability. To aid decision-making, new insights are needed into how water distribution system reliability to climate-driven heat will change, and the proactive maintenance strategies available to combat failures. To this end, we present the model Perses, a framework that joins a water distribution network hydraulic solver with reliability models of physical assets or components to estimate temperature increase-driven failures and resulting service outages in the long term. A theoretical case study is developed using Phoenix, Arizona temperature profiles, a city with extreme temperatures and a rapidly expanding infrastructure. By end-of-century under hotter futures there are projected to be 1%–5% more pump failures, 2%–5% more PVC pipe failures, and 3%–7% more iron pipe failures (RCP 4.5–8.5) than a baseline historical temperature profile. Service outages, which constitute inadequate pressure for domestic and commercial use are projected to increase by 16%–26% above the baseline under maximum temperature conditions. The exceedance of baseline failures, when compounded across a large metro region, reveals potential challenges for budgeting, management, and maintenance. An exploration of the mitigation potential of adaptation strategies shows that expedited repair times are capable of offsetting the additional outages from climate change, but will come with a cost.

A dynamic delay-based reliability evaluation model for communication networks

The traditional network reliability research generally focuses on the topological connectivity among given nodes based on graph theory. Without considering the relationship between network failures and network performance degradation, traditional network reliability analysis cannot reflect actual network ability reaching up to a certain accomplishment level over a utilization interval. As for the performability analysis of network with specific requirement of transmission time, this paper proposes a dynamic delay-based network reliability evaluation method, which considers network’s ability that transmission delay can be controlled under expected upper limit level in the course of network normal operating period, and puts forward a three-layer network reliability analysis architecture. By integrating a network component reliability model, a network topology model and a network performance model, the dynamic delay-based network reliability model is established, and the network reliability influence factors are integrated into network reliability evaluation. A simple example shows that for a given network, network reliability is different from specified performance requirement. Furthermore, network failures will result in network performance degradation in network long-term operation. It is also proven that network reliability relates not only to network topological connectivity but also to network application environment and specified performance requirement. The key contribution of this paper is to guide network engineers to design a high performance network by optimizing the network parameters according to the delay-based network reliability evaluation method proposed in this paper.

Reliability assessment of offshore oil platform power system based on state enumeration method

Based on the state enumeration method, a reliability evaluation method for offshore platform power system is proposed in this paper. Firstly, the reliability model of land-based components and the modelling method of the system are introduced. In reliability evaluation, all fault states are generated based on state enumeration method, power supply circuit sets are identified based on depth-first algorithm. The effects and losses of multiple faults are calculated based on platform maintenance capability, and fault time and load-loss time are separated and counted. Finally, taking an offshore oil platform as an example, the outage table of the system is generated, and the reliability index of the system is obtained, which verifies the effectiveness and accuracy of the method proposed in this paper.

Elaborate Reliability Evaluation of Cyber Physical Distribution Systems Considering Fault Location, Isolation and Supply Restoration Process

The existing reliability models of the cyber physical distribution systems, which are mostly based on some simplified assumptions, cannot accurately evaluate the reliability of complex cases in practical engineering applications. To solve this problem, an elaborate reliability evaluation method considering the whole process of fault location, isolation and supply restoration is proposed. This paper establishes reliability models of components and the two systems, summarizes the mapping relationship between various cyber system failures and the physical fault handling into several laws, proposes the reliability evaluation procedure in the framework of Monte Carlo method, and verifies the feasibility and effectiveness of the method in an actual distribution network cyber physical system. In the proposed method, the multiple component characteristics, complex topological structure, coupling relationship of the cyber-physical distribution systems, and the actual human-computer joint participation are considered in the analysis of fault location, isolation and supply restoration process, which provides a effective and accurate theory for the application of reliability evaluation in the actual distribution network and prosumer energy management system.

A Hybrid Framework for Short-Term Risk Assessment of Wind-Integrated Composite Power Systems

This paper proposes a new framework for the short-term risk assessment of wind-integrated composite power systems via a combination of an analytical approach and a simulation technique. The proposed hybrid framework first employs the area risk method—an analytical approach, to include the detailed reliability models of different components of a power system. In this regard, a novel reliability modeling approach for wind generation for short-term risk assessment is also proposed. Thereafter, a non-sequential Monte-Carlo simulation technique is adopted to calculate the partial risks of the area risk method. As a result, the proposed framework is also capable of including the contingencies and constraints of the transmission system that are customarily neglected in the area risk method. The computational performance of the proposed framework is greatly enhanced by adopting the importance of sampling technique, whose parameters are obtained using the cross entropy optimization. Case studies performed on a modified 24-bus IEEE Reliability Test System validate that the detailed reliability modeling of wind generation and consideration of the transmission system are necessary to obtain more accurate short-term risk indices. Furthermore, the computational performance of the proposed framework is many orders higher than any other comparable methods.

General Stress-Strength Interference and Gamma Process Combined Method for Space Solar Cell Components Reliability Analysis

Space solar cell components always suffered from the complex and hostile space environment. The reliability of space solar cell components is important to ensure the mission success of space satellites. However, the current research mostly focuses on solar cells' degradation mechanisms. There is less research based on the performance parameters of space solar cell component's degradation to analyze its reliability. Therefore, a reliability analysis method based on the method of modeling the performance degradation of space solar cell components is proposed. By combining general stress-strength interference model and Gamma process, the reliability model of space solar cell components is established. The accelerated degradation test based on the equivalent particle dose is performed to simulate the radiation influence and verify the proposed method. Compared with the displacement damage dose method, the proposed method can further develop the reliability analysis based on performance degradation analysis. Moreover, the cover glass and interconnection are also taken into account together to form a completed component analysis. Through analyzing the cover glass and interconnection experiment results, the cover glass can affect the component reliability; whereas, the interconnection has little influence at the particle radiation condition. Based on the proposed method, the reliability is easier to calculate with the degradation of output power.

RETRACTED: Reliability analysis of mechanical components based on a nonlinear fatigue damage accumulation model

The dynamic reliability models of mechanical components with the failure mode of fatigue are mainly based on the linear damage accumulation theory, which is also called the Miner’s rule. But the Mi...

A Fast Method for Reliability Evaluation of Ultra High Voltage AC/DC System Based on Hybrid Simulation

The construction and operation of the ultrahigh voltage power grid has solved the problem of optimal allocation of energy resources and played a key role in promoting social development. However, concerns about its safety have kept growing in recent years. In order to analyze the reliability of ultrahigh voltage AC/DC system combined with the quasi-Monte Carlo method and PSD-BPA simulation, the reliability model of various components and system is established, and the simulation speed is improved with accuracy ensured. In order to ensure the compatibility and efficiency of the software, we design the BPA-Matpower data interface, and the data translation from BPA to Matpower is realized by fourth conversion. Then, we propose an index system for reliability evaluation, concise and easy to compute, to reflect the reliability of the UHV grids and the characteristics of AC and DC systems. Based on actual regional powergrid, we compare the model in this paper with the traditional sequential Monte Carlo method, and carry out the analysis of the component sensitivity to study the multi-fault characteristics and the weakness of the system, and verify the scientific and effective result of this paper.

Reliability Model of Consecutive $(2, k)$ -Out-of-( $2, n$ ) :F Systems With Local Load-Sharing

Most previous reliability models of consecutive k-out-of-n system assume that the components are independent or their reliabilities are equal. The system reliability can be obtained according to the configuration of $k$ consecutive failed components. However, for consecutive $(2,k)$ -out-of- $(2,n)$ systems with local load-sharing, workloads on failed components will be equally shared by both vertically and horizontally adjacent components. Consequently, the component failure probability density function (FPDF) may be unequal and dependent on the actual load (both original and sharing load), which is determined by the states of adjacent components. Furthermore, the component FPDF may be time-varying with the failure sequences of adjacent components. Therefore, reliability modeling must consider the component dynamic process determined by the failure sequences of adjacent components, instead of the static configuration determined by failure states of adjacent components in the traditional models. To solve the above issues, this paper develops a new reliability model for consecutive $(2,k)$ -out-of- $(2,n)$ systems with local load-sharing. The system and component dynamic processes are automatically searched and combined into a set of state transition paths. In each path, the component load-varying process can be confirmed, by considering the influence of adjacent failures on its shared load. Based on the state transition paths, the component and system reliability models are further derived, according to the confirmed load processes of each component. Finally, we present graphical illustrations of the reliability evaluation of cable-strut systems in long-span suspension bridges.

Reliability Evaluation of Machine Center Components Based on Cascading Failure Analysis

In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influenced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm. Based on the comprehensive failure probability function and total probability formula, the inherent failure probability function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following: 1) The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2) The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree of the system component, which provides a theoretical basis for reliability allocation of machine center system.

Software reliability prediction using SPN

Reliability is an important software quality parameter. In this research for computation of software reliability, component reliability model based on SPN would be proposed. An isomorphic markov chain is obtained from component SPN model. A quantitative reliability prediction method is proposed. The component reliability value is calculated according to the transition cumulative probability distribution of markov chain, obtained from the software SPN model. By means of reliability prediction of the whole software, we'll introduce CRMPN. In CRMPN states are component reliability model and transition are marked with components reliability. With this research more complex software could be simplified and reliability of the software could be evaluated effectively. An example is provided for demonstrating the feasibility and applicability of our method.Keywords: Reliability, SPN, Markov Chain, Component based-software

Discrete Markov Approach for Building Component Condition, Reliability, and Service-Life Prediction Modeling

AbstractCondition indexes have been developed to measure building component condition degradation due to age, use, and deterioration in support of asset management tasks related to work identification, planning, and prioritization. With the development of these indexes, a vast amount of condition index data have been collected for a wide range of components in buildings of varying type, use, and geographic location. The U.S. Department of Defense has implemented a standardized condition-assessment approach applied to thousands of Department-owned buildings, resulting in a vast condition index dataset to support more in-depth study of building component condition and reliability. This paper explores the existing data and develops a rigorous definition of the relationship between component condition, failure, and reliability. Presented is an approach using Markov transition probabilities to analyze the existing component condition datasets. This approach provides an improved method for predicting future con...

Integrated Component Reliability Modeling for Helicopter Service Industry

A helicopter service industry is concerned with component reliability, as poor component reliability jeopardizes the safe operation of aircraft. Currently the maintenance process used for component overhauls and replacements is typically based on the maximum intervals called Hard Time (HT) limits recommended by manufacturer without using the real-world reliability data. In this case study, an integrated component reliability modeling procedure using is proposed to identify proper component overhaul and replacement intervals for a leading helicopter service industry. This procedure considers analysis methods including removal rate analysis, mean time between failure (MTBF) analysis, average life analysis, data distribution analysis, and total quality management (TQM) shop survey which can be used as a framework to support reliability programs in the helicopter industry, working as a decision-support tool for the modification of manufacturer’s recommended intervals. An illustrative example is provided to show the use of this modeling procedure. Future work could be done to correlate inventory analysis using component reliability modeling leading to total productive maintenance.

Имитационное моделирование аварийных ситуаций в гидравлических системах

The technology of information support of the hydraulic component reliability models based on computational experiment. The results of simulations of hydraulic systems based on the criterion of dependence. The forecast loss of capacity based only on the data analysis of the flow distribution in the undisturbed state