reliability indices
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2022 ◽  
Author(s):  
P. Gubarev

Abstract. The authors describe the analysis of the current state of the problem under consideration. A definition of "averaged failure flow parameter" is given. The periods of traction rolling stock life cycle are considered. The assumption of event distribution laws exponentiality is introduced, which makes it possible to obtain expressions of the main reliability indices in the analytical form. The work of depot service locomotives to ensure the required reliability and readiness of the rolling stock during their normal operation has been assessed. The introduction of the term "readiness" into the modern practice of traction rolling stock reliability estimation is considered. The initial data for calculating the indexes of locomotive uptime and readiness are presented. Calculated values of readiness and no-failure indices of electric locomotives in operation are obtained. The calculated values of internal and technical availability coefficients are compared with similar indicators established by technical specifications. Control procedures were performed to determine the compliance of each set of locomotives (EP1, 2ES4K) with the uptime requirements. As a result of comparing the calculated values of internal and technical availability factors (for electric locomotives EP1 and 2ES4K with analogous values set by specifications (EP1 and 2ES4K) it was determined that the surveyed locomotives comply with the established availability requirements. As a result of control procedures to determine the compliance of each set of EP1 and 2ES4K locomotives with the uptime requirements, it was determined that the set of 2ES4K electric locomotives for the run in question does not fully comply with the uptime requirement. And the set of EP1 electric locomotives meets the reliability requirements, but the error value is higher than 20%. To clarify both events, it is necessary to increase the mileage interval of the locomotives and repeat the procedure for determining compliance with the uptime requirements. The method of assessing the uptime and readiness of locomotives during their normal operation makes it possible to identify existing shortcomings in the operation of rolling stock and to form measures to improve the quality of rolling stock operation.


2022 ◽  
Vol 17 ◽  
pp. 1-8
Author(s):  
V. Veretekhina Svetlana

This article presents the mathematical modeling of export energy costs. The knowledge-intensive products export energy costs are a set of financial, material, labor costs and resources consumption. Export costs are a multilevel system of indicators. The author sets out the order of mathematical modeling. At the first stage, the main trends in reducing export energy costs are identified. A set of integrated logistics support measures is modeled. The modeling of knowledge-intensive products export energy costs is a system of technical and economic indices and a cost value dependance: Maintenance and Repair, Material and Technical Maintenance, Business Model of After-Sales Service, Formation of the Cost of Insurance and Investment Management Strategy. Formulas, practical calculation examples and graphs are presented. The Ishikawa systematic analysis method is used to visualize data and dependence relations. The author's mathematical modeling of knowledge-intensive products export costs includes the calculation of integrated logistic support costs. Exporting countries require a high level of technical products efficiency. It has been established that "the more complex a knowledge-intensive products is, the higher the reliability of systems is". Reliability indices are basic. The author's scientific study confirms a hypothesis of the knowledge-intensive products export feasibility only with high reliability and efficiency factors. The author developed a set of integrated logistical support measures for knowledge-intensive products.


2022 ◽  
pp. 958-977
Author(s):  
Baseem Khan ◽  
Mesfin Fanuel

Due to the transition of traditional power system to smart structure, integration of renewable energy sources is of great importance. It is performed by using distributed generators and Micro grid. Integration of renewable sources is very useful for the reliability enhancement of distribution system as energy can be supplied locally at distributed level. Therefore, this chapter provides an overview of various reliability methods which are utilized for finding the impact of renewable energy generation on distribution system reliability assessment. These renewable energy sources are integrated in the distribution system at distributed and Micro grid level. Various characteristics of renewable energy sources are discussed to model them. A general problem of reliability assessment in terms of reliability indices is also discussed.


2022 ◽  
pp. 25-37
Author(s):  
Sanchari Deb ◽  
Sulabh Sachan

The growing concern about fossil energy exhaustion, air pollution, and ecological deprivation has made electric vehicles (EVs) a practical option in contrast to combustion engine-driven vehicles. In any case, driving extent uneasiness is one of the innate inadequacies related with EVs. Massive integration of EV charging load into the power system may be a threat to the distribution network. Spontaneous situation of charging stations in the distribution system and uncoordinated charging will augment the load demand thereby resulting in voltage instability, deterioration of reliability indices, harmonic distortions, and escalated power losses. This chapter will concentrate on breaking down the effect of EV chargers on the working parameters, for example, voltage dependability, unwavering quality, and force misfortune. The examination will be completed on standard test systems. The discoveries of the proposed part will evaluate the effect of EV charging load on the working parameters of the distribution system and help in proposing a framework for charging station planning.


2021 ◽  
Vol 33 (6) ◽  
pp. 293-297
Author(s):  
Dong Hyawn Kim ◽  
Jungwon Huh

Calibration of load-resistance factors for the limit state design of front covered caisson breakwaters were presented. Reliability analysis of the breakwaters which are constructed in Korean coast was conducted. Then, partial safety factors and load-resistance factors were sequentially calculated according to target reliability index. Load resistance factors were optimized to give one set of factor for limit state design of breakwater. The breakwaters were redesigned by using the optimal load resistance factor and verified whether reliability indices larger than the target value. Finally, load-resistance factors were compared with foreign country’s code for verification.


2021 ◽  
Vol 8 (6) ◽  
pp. 861-870
Author(s):  
S. Vinoth John Prakash ◽  
P.K. Dhal

The output of wind and the solar system is not constant; it is difficult to access the adequacy of the system. The Generation model is developed for 240 MW of different generation units in the Roy Billinton Test System (RBTS). Then a multi-state wind and solar generation model is developed based on different solar radiation and wind speed to evaluate the probability of the states. In this work, the wind and solar systems are studies for separate locations with each consist of 8 MW, 18 MW, 28 MW, and 38 MW generation capacities. This wind and solar generation model are applied to Roy Billinton Test System (RBTS) to evaluate the reliability indices like Loss of Load Expectation (LOLE). Based on the development of the MATLAB program for determining reliability indices, the capacity outage probability is developed for multiple solar and wind states. Based on standard load forecasting and the Time Series Load forecasting technique, the reliability of the system is analyzed. The results reveal the variation of risk indices in the system when additional generators are incorporated into the RBTS generation system. The cost optimization for Solar and Wind system were conducted using HOMER software to obtain the levelized cost of the proposed system.


Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3182
Author(s):  
Afroz Alam ◽  
Mohd Tariq ◽  
Mohammad Zaid ◽  
Preeti Verma ◽  
Marwan Alsultan ◽  
...  

There is a need for the optimal positioning of protective devices to maximize customers satisfaction per their demands. Such arrangement advances the distribution system reliability to maximum achievable. Thus, radial distribution system (RDS) reliability can be improved by placing reclosers at suitable feeder sections. This article presents comprehensive details of an attempt to determine the reclosers’ optimal location in an RDS to maximize the utility profit by reliability improvement. Assessment of different reliability indices such as SAIDI, SAIFI, CAIFI, CAIDI, etc., with recloser placement, exhibits a considerable improvement in these indices in contrast with the absence of recloser. Consequently, a new bidirectional formulation has been proposed for the optimized arrangement of reclosers’. This formulation efficiently handles the bidirectional power flow, resulting from distributed generation (DG) unit (s) in the system. The proposed model has been solved for a test system by utilizing the Genetic algorithm (GA) optimization method. Later, test results conclude that reclosers’ optimal placement contributes significantly towards utility profit with minimum investment and outage costs.


2021 ◽  
Vol 13 (2) ◽  
pp. 13-20
Author(s):  
Bülent O. Miçooğullari ◽  
◽  
David J. Edwards ◽  
Rıdvan Ekmekçi ◽  
◽  
...  

The purpose of this research was to examine the reliability and validity of Bull’s Mental Skills Questionnaire (BMSQ), measuring seven psychological skills resulting in a total scale score, within Turkey. The sample consisting of 163 males and 131 females, totaling 294 athletes, completed the 28 item BMSQ. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were undertaken. EFA results yielded a satisfactory seven-factor solution, the same as the English version. Cronbach alpha (α) reliability indices were as follows: concentration ability (0.71), anxiety and worry management (0.63), relaxation ability (0.69), imagery ability (0.73), self-confidence (0.72), motivation (0.64) and mental preparation (0.52). The BMSQ explained 62% of the total variance. Moreover, model fit indices calculated during CFA for the 28 item and 7 sub-dimensions model of BMSQ indicated an acceptable fit [Chi-Square (ꭓ²)=541.2, df=328, ꭓ²/df=1.65, Root Mean Square Error Approximation (RMSEA)=0.05, Comparative Fit Index (CFI)=0.95, Goodness of Fit Index (GFI)=0.90, Normed Fit Index (NFI)=0.89, and Non Normed Fit Index (NNFI)=0.90]. Thus, the original 7-factor solution was supported with the data collected from Turkish participants. Results demonstrated that the BMSQ is a valid and reliable instrument for the Turkish population.


2021 ◽  
Vol 32 (4) ◽  
pp. 84-101
Author(s):  
G. Sengi ◽  
E. Ntagwirumugara

The existing power distribution system of the city of Goma in the Democratic Republic of the Congo has many problems, including the scarcity of electric energy, power unreliability, the low access rate of electrification, poor flexibility in the network topology, and lack of demand response, which lead to shedding of load, unbalancing and overloading the system. The reliability of the Goma power distribution system is very poor by international standards. The major cause of this is the lack of adequate energy supply to meet demand. To mitigate the power reliability problem, a solar-based distributed generation (DG) is modelled and evaluated in this study. Each feeder has been considered separately with an appropriately designed DG. The work has evaluated initial investment cost and life cycle cost of the investment to assess the feasibility of the proposed solution. Based on the unserved energy and electricity tariff, an economic analysis was conducted. The reliability indices are computed and the modelled solution is designed for each feeder in PV syst software and simulated using ETAP, whose simulation results show that the reliability can be improved by up to 76%.  


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