Analysis of distribution laws of transformer oil indicators in 110-330 kV transformers

Introduction. Ensuring the operational reliability of power transformers is an urgent task for the power industry in Ukraine and for most foreign countries. One of the ways to solve this problem is the correction of maximum permissible values of insulation parameters. However, such a correction is fundamentally impossible without an analysis of the laws of distribution of diagnostic indicators in the equipment with different states. The purpose of the research is to analyse the laws of distribution of the quality indicators of transformer oil with different states in 110 and 330 kV transformers. Novelty. It was found that both 330 kV autotransformers and 110 kV transformers have the displacements between the mathematical expectations of the distribution density of usable oil indicators. It caused by different service life of the analysed transformers and different values of load factors. This indicates the need to consider the influence of these factors when correcting the maximum permissible values of oil indicators. Also, the presence of displacement between the distribution densities of some indicators of usable oil in 110 kV transformers and 330 kV autotransformers has been revealed. It indicates a different intensity of oxidation reactions in transformers with different voltage class. In order to reduce the heterogeneity of initial data the procedure of statistical processing of in-service test results has been proposed as a method. This procedure combines the use of a priori information about the service life of equipment and values of load factors with the elements of statistical hypothesis testing. The results of the analysis of the distribution laws of transformer oil indicators with different states have shown that for both usable and unusable oil the values of oil indicators obey the Weibull distribution. Values of the shape and scale parameters for each of the obtained indices arrays have been obtained, as well as calculated and critical values of the goodness-of-fit criteria. Practical value. Obtained values of the distribution law parameters of the transformer oil indicators with different states, considering the service life and operating conditions allow to perform the correction of the maximum permissible values of the indicators using the statistical decision-making methods.

Composition and superposition failures probability distribution laws for assessing military electrical products reliability

An implementation of the developed computational structural method for assessing the reliability of complex electrical products. The basis of this method is the use of combinations of composition and superposition laws of distribution of probabilities of failures. The estimation of reliability of a rotating transformer type ВT-5. The calculated reliability indices are compared with results of standard test ВT-5 for reliability. Received high convergence of the results.

Evaluation of reliability of quickly repairable components of transshipment machines and mechanisms

When calculating the reliability indicators of transshipment machines and mechanisms, the required values are not always obtained explicitly due to systematic difficulties (complex distribution laws) or limited initial data. The optimal stock of spare parts for transshipment machines and mechanisms depends on the reliability indicators, and the nature and intensity of their use. Downtime due to the failure of transshipment machines and mechanisms used for ship handling leads to greater losses than downtime of these machines in the warehouse. Failures of transshipment machines and mechanisms can be due to the failure of non-repairable and quickly repairable components, and those with a long repair time. To calculate the main reliability indicators of quickly repairable components, the most common laws of distribution of random variables were employed. The paper considers the methodological aspects of the probabilistic reliability estimate of quickly repairable components of transshipment machines and mechanisms.

ABOUT THE LAWS OF THE DISTRIBUTION OF THE TENSIONING FORCES OF THE CABLES IN UNDERWATER ANCHOR-CABLE MOBILE ROBOTS

Possibilities of synthesis of various laws of distribution of the tension force of cables in the modules of the anchor-cable mover are considered. The analysis of the features of several variants of the distribution of tensile forces is carried out.

APPLICATION OF A STATISTICAL APPROACH TO THE ANALYSIS OF RISKS OF LIFT EQUIPMENT OPERATION

Приведены исследования, относящиеся к тематическому направлению оценки риска эксплуатации лифтового оборудования при помощи статистического подхода. Субъективность методов квалиметрической оценки снижения рисков эксплуатации лифтов дала возможность авторам предложить статистический подход к оценке во всех случаях, где это возможно. Наиболее сложными и ответственными этапами анализа и оценки риска эксплуатации лифтового оборудования является сбор информации, необходимой для установления законов распределения сроков службы и определения гамма-процентных ресурсов его конструктивных элементов, а также детальное изучение всех обстоятельств возникновения этих отказов. Анализ статистических данных, проведенный авторами, позволил исследовать долговечность отдельных элементов лифтового оборудования и использовать эти данные для оценки срока службы и обоснования рисков эксплуатации как лифта в целом, так и отдельных его элементов. А проведение анализа причин выхода из строя элементов оборудования позволилo дать оценку необходимости проведения мероприятий по повышению их сроков службы, надежности и качества обслуживания. Современные методы компьютерной обработки информации в сочетании с внедрением системы самодиагностики лифтового оборудования могут существенно повысить эффективность системы технического обслуживания лифтов, а своевременное диагностирование - минимизировать аварии и обеспечить безопасность передвижения The article presents studies related to the thematic area of risk assessment of the operation of elevator equipment using a statistical approach. The subjectivity of the methods of qualimetric assessment of reducing the risks of operating elevators made it possible to propose a statistical approach to assessment in all cases where it is possible. The most difficult and crucial stages of the analysis and risk assessment of the operation of elevator equipment is the collection of information necessary to establish the laws of distribution of service life and determine the gamma-percentage resources of its structural elements, as well as a detailed study of all the circumstances of these failures. The analysis of statistical data that we carried out made it possible to investigate the durability of individual elements of the elevator equipment and use these data to assess the service life and substantiate the risks of operating both the elevator as a whole and its individual elements. And the analysis of the reasons for the failure of equipment elements made it possible to assess the need for measures to increase their service life, reliability, and quality of service. Modern methods of computer processing of information in combination with the introduction of a self-diagnostic system for elevator equipment can significantly increase the efficiency of the elevator maintenance system, and timely diagnostics can minimize accidents and ensure the safety of operation

The laws of distribution of some parameters when organizing the movement of trains

The article discusses the key factors for the organization of train traffic. The analysis of statistical parameters of the intervals of departure of freight trains from railway stations and the length of the freight train flow is carried out. Based on these train schedules, graphical dependences of the intervals of departure of trains from separate points on the volume of train traffic and the distribution of train lengths in even and odd directions are constructed. Polynomial dependencies with coefficients of variation are derived. The curve of the second-order Erlang distribution function for the departure intervals is constructed. It is determined that the average departure intensity in one hour is equal to three trains, and the average departure interval lies between the 25th and 35th minutes with a probability of 0.793. There is a correlation between the coefficient of variation (mean square deviation) of the departure interval and its average daily deviation. The power function of the analytical ratio of the coefficient of variation from the average interval of departure of freight trains from the technical stations of the Krasnoyarsk railway during the day is determined using the least squares method. The degrees of correspondence of theoretical and statistical distributions of the number of cars in trains are studied using the Kolmogorov criterion with the calculation of the probability value and confirmation that the distribution of the number of cars in trains obeys the binomial law. Using the Pearson agreement criterion, it is proved that the frequency of departure of freight trains from railway stations obeys the exponential distribution law.

Physiological and psychological basis of aesthetics

From colors and paints, we now turn to the form of objects, that is, to the presentation of aesthetic conditions and laws of distribution and combination of lines that limit the subject. Color, as we saw, depends on different excitations of different kinds of fibers of the optic nerve; the form depends on the number and relative position of the nerve fibers excited in this way. The eye, initially, can perceive only the length in its two dimensions, that is, the plane of the figure.

SUMMARY REQUIRING REGARDLESS OF CREATION DECISION SUPPORT SYSTEM FOR THE DISTRIBUTION CAPABILITIES TO PROVIDE SUFFICIENT EFFICIENCY OF BORDER REGION OF SYSTEMS FOR OPTO-ELECTRONIC SURVEILLANCE

The article is devoted to the substantiation of the choice of the basic methodology for assessing the effectiveness of the optoelectronic surveillance system, which could be taken as the basic model of this system for the distribution of forces and means to ensure a sufficient level of border protection efficiency. taking into account in the specified basic methodology for assessing the effectiveness of the system. As a result of the study it was found that as a basic method of assessing the effectiveness of the optoelectronic surveillance system, it is advisable to adopt a method based on a probabilistic approach to describe the processes that accompany the functioning of the optoelectronic surveillance system. It is also substantiated that the main provisions that need to be taken into account when creating a decision support system for the distribution of forces and means to ensure a sufficient level of border protection in the field of optoelectronic surveillance are: homogeneous in terms of features of technical means of border protection time periods; adequate integrated laws of distribution of time periods, which determine the probability of non-detection of the target to its approach to a given distance by certain technical means of border protection, which are part of the studied system of optoelectronic surveillance; points of "stitching" of various integral laws of distribution at the ends of the specified periods; the impact of weather changes over a period of time, which characterizes the period of the service organization, on the functioning of the system; "Dead" zones, which are dynamically variable depending on the natural and man-made conditions that arise in the area of responsibility.

Mathematical simulation of error functions of decision-making at tolerance control of measuring techniques availability

Analytical and computer models of false failure and undetected failure (error functions) were developed with tolerance control of the parameters of the components of the measuring technique. A geometric interpretation of the error functions as two-dimensional surfaces is given, which depend on the tolerance on the controlled parameter and the measurement error. The developed models are applicable both to theoretical laws of distribution, and to arbitrary laws of distribution of the measured quantity and measurement error. The results can be used in the development of metrological support of measuring equipment, the verification of measuring instruments, the metrological examination of technical documentation and the certification of measurement methods.