Fault characteristics analysis and protection design for MMC-UPFC with high reliability

2018 ◽  
Author(s):  
Zhixin Pu ◽  
Shensen Zha ◽  
Liu Zong ◽  
Ying Wang ◽  
Shujun Liu ◽  
...  
Keyword(s):  
High Reliability ◽  
Characteristics Analysis

The design and characteristics analysis of lunar based Two Axes gimbal with high reliability

2011 ◽  
Author(s):  
Jing Huang ◽  
Zhao-hui Liu ◽  
Zhi-guo Li ◽  
Zhi-yuan Chang ◽  
Xin Shi
Keyword(s):  
High Reliability ◽  
Characteristics Analysis

scholarly journals DYNAMIC CHARACTERISTICS ANALYSIS OF BLADED DISK TURBOMACHINES BASED ON INTENTIONAL MISTUNING

2020 ◽  
pp. 61-70
Author(s):  
Oleg Repetckii ◽  
◽  
Van Vinh Nguyen ◽  
Keyword(s):  
Dynamic Characteristics ◽  
High Reliability ◽  
Forced Response ◽  
Rotor Blades ◽  
Design Stage ◽  
Bladed Disk ◽  
Rotor Design ◽  
Urgent Task ◽  
Characteristics Analysis ◽  
Engine Excitation

To increase technical level of energy turbomachine in modern turbomachinery, high reliability and durability of structures are required in the design, manufacture and operation of turbomachine. Any change geometry, mass, material properties of the bladed disk of turbomachine in the design is called mistuning parameters. With a small value of mistuning blades can significantly increase amplitude, displacement or stresses of the blades structures. So, analysis influence of the effect mistuning parameters on the dynamic characteristics in the field of turbomachine is an important and urgent task. This article analyzes the effect intentional mistuning of the axial bladed disk turbomachine in order to reduce forced response due to low-order engine excitation. The maximum value forced response of rotor blades turbomachine with mistuning parameters is usually much more than that of the tuned rotors. An increase level mistuning of this critical value actually leads to a decrease magnifications of the forced response. Thus, the actual work has been introducing some degree of intentional mistuning in the design to achieve these purposes. In this paper, we study the effectiveness of intentional mistuning at the design stage bladed disk turbomachine, which is introduced into the rotor design by changing the nominal mass of the blades in harmonic Формаls.

The Different Hopping Methods Mathematical Models

2021 ◽  
pp. 10-13
Author(s):  
Ольга Алексеевна Борисенко ◽  
Ирина Николаевна Грибкова
Keyword(s):  
Classical Method ◽  
High Reliability ◽  
Yeast Cells ◽  
Vital Activity ◽  
Medium Ph ◽  
Ph Influence ◽  
Beer Maturation ◽  
Study Results ◽  
Characteristics Analysis ◽  
Qualitative Characteristics

Статья посвящена вопросу сравнения двух способов охмеления - классического и инновационного «холодного» способа внесения хмеля при дображивании пива, - а именно оценке основных факторов процесса, влияющих на интенсивность образования изоксантогумола, характеризующего тона горечи в пиве. Приведены результаты исследования качественных показателей модельных растворов, позволяющих минимизировать влияние прочих органических соединений на уровень содержания изоксантогумола в среде. Математическая оценка зависимостей позволила получить многофункциональные уравнения зависимости содержания изоксантогумола от ряда параметров, играющих важное значение при различных способах охмеления в технологии пивоварения. Математический анализ позволил выявить высокую достоверность полученных данных. Анализ полученных качественных характеристик в доверительном интервале р ≥ 0,95 позволил при классическом способе охмеления выявить влияние рН среды, а при «холодном» способе - живых дрожжевых клеток, преобразующих ксантогумол в изоформу. Основная часть полученных результатов согласовалась с ранее полученными относительно влияния рН, продолжительности охмеления, корреляции количества полифенолов, уровня изоксантогумола. Однако, влияние жизнедеятельности дрожжевых клеток не было отмечено ни в одном труде, что требует дополнительного экспериментального исследования. The article is devoted to the issue of comparing two hopping methods - the classical and innovative «dry hopping» method during the beer maturation, namely, the process main factors assessment that affect the isoxanthohumol formation intensity, which characterizes the beer bitterness tone. The model solutions qualitative indicators study results, which allow minimizing the effect of other organic compounds on the level of isoxanthohumol content in the medium, are presented. The dependences mathematical assessment made it possible to obtain multifunctional equations for the dependence of the isoxanthohumol content on several parameters that play an important role in various methods of hopping in brewing technology. Mathematical analysis made it possible to reveal the high reliability of the data obtained. The obtained qualitative characteristics analysis in the confidence interval p ≥ 0.95 made it possible to reveal the medium pH influence with the classical method of hopping, and with the «dry hopping» method - living yeast cells that convert xanthohumol into an isoform. Most of the results obtained were consistent with those previously obtained regarding the effect of pH, duration of hopping, and the correlation between the polyphenols amount and the isoxanthohumol level. However, the influence of the yeast cells vital activity was not noted in any work, which requires additional experimental research.

Typical Insulation Defects Simulation and Signal Characteristics Analysis of GIS Partial Discharge

2014 ◽  
Vol 521 ◽  
pp. 394-398 ◽  
Author(s):  
Kang Ning Wang ◽  
Tian Zheng Wang ◽  
Jie Yan
Keyword(s):  
Pulse Current ◽  
High Reliability ◽  
Ultrasonic Method ◽  
Partial Discharge ◽  
Current Method ◽  
Metal Particles ◽  
Signal Characteristics ◽  
Insulation Defect ◽  
Characteristics Analysis ◽  
Long Time

Gas insulated switchgear (GIS) has excellent performances such as small area, not affected by atmosphere, high reliability. So it has been used more and more widely in the power system. However, But the partial discharge (PD) would occur because of insulation defect, PD will lead to the GIS insulation damage after a long time, and will lead to serious consequences without treatment in time, therefore, the PD detection is particularly important. Article simulates the high voltage conductor spikes, basin insulator metal particles on the surface and the shell spike the insulation of the three kinds of typical defects, using the pulse current method and ultrasonic method to test partial discharge signals and get the corresponding signal characteristics, which play a certain guiding significance for field applications.

Failure Analysis With the Scanning Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 482-483
Author(s):  
John R. Devaney
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
High Reliability ◽  
Military Applications ◽  
Small Structure ◽  
Useful Life ◽  
Insight Into ◽  
Scanning Electron

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.

Fuzzy multi-objective location and routing problem

2020 ◽  
Vol 39 (3) ◽  
pp. 3259-3273
Author(s):  
Nasser Shahsavari-Pour ◽  
Najmeh Bahram-Pour ◽  
Mojde Kazemi
Keyword(s):  
Firefly Algorithm ◽  
High Reliability ◽  
Research Area ◽  
Nsga Ii ◽  
Location Routing Problem ◽  
Routing Problem ◽  
Location Allocation ◽  
Multi Objective ◽  
Location Routing ◽  
The Cost

The location-routing problem is a research area that simultaneously solves location-allocation and vehicle routing issues. It is critical to delivering emergency goods to customers with high reliability. In this paper, reliability in location and routing problems was considered as the probability of failure in depots, vehicles, and routs. The problem has two objectives, minimizing the cost and maximizing the reliability, the latter expressed by minimizing the expected cost of failure. First, a mathematical model of the problem was presented and due to its NP-hard nature, it was solved by a meta-heuristic approach using a NSGA-II algorithm and a discrete multi-objective firefly algorithm. The efficiency of these algorithms was studied through a complete set of examples and it was found that the multi-objective discrete firefly algorithm has a better Diversification Metric (DM) index; the Mean Ideal Distance (MID) and Spacing Metric (SM) indexes are only suitable for small to medium problems, losing their effectiveness for big problems.

Are Public Bureaucracies Supposed to Be High Reliability Organizations?

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Wolfgang Seibel
Keyword(s):  
Child Protection ◽  
Organization Theory ◽  
Goal Attainment ◽  
High Reliability ◽  
Human Action ◽  
High Reliability Organizations ◽  
Fine Grained ◽  
Trade Offs ◽  
Public Bureaucracy ◽  
Account Standard

This article addresses the question of to what extent conventional theories of high reliability organizations and normal accidents theory are applicable to public bureaucracy. Empirical evidence suggests precisely this. Relevant cases are, for instance, collapsing buildings and bridges due to insufficient supervision of engineering by the relevant authorities, infants dying at the hands of their own parents due to misperceptions and neglect on the part of child protection agencies, uninterrupted serial killings due to a lack of coordination among police services, or improper planning and risk assessment in the preparation of mass events such as soccer games or street parades. The basic argument is that conceptualizing distinct and differentiated causal mechanisms is useful for developing more fine-grained variants of both normal accident theory and high reliability organization theory that take into account standard pathologies of public bureaucracies and inevitable trade-offs connected to their political embeddedness in democratic and rule-of-law-based systems to which belong the tensions between responsiveness and responsibility and between goal attainment and system maintenance. This, the article argues, makes it possible to identify distinct points of intervention at which permissive conditions with the potential to trigger risk-generating human action can be neutralized while the threshold that separates risk-generating human action from actual disaster can be raised to a level that makes disastrous outcomes less probable.

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