Predicting the technical condition of the power transformer using fuzzy logic and dissolved gas analysis method

Power transformers are one of the most important and complex parts of an electric power system. Maintenance is performed for this responsible part based on the technical condition of the transformer using a predictive approach. The technical condition of the power transformer can be diagnosed using a range of different diagnostic methods, for example, analysis of dissolved gases (DGA), partial discharge monitoring, vibration monitoring, and moisture monitoring. In this paper, the authors present a digital model for predicting the technical condition of a power transformer and determining the type of defect and its cause in the event of defect detection. The predictive digital model is developed using the programming environment in LabVIEW and is based on the fuzzy logic approach to the DGA method, interpreted by the key gas method and the Dornenburg ratio method. The developed digital model is verified on a set of 110 kV and 220 kV transformers of one of the sections of the distribution network and thermal power plant in the Russian Federation. The results obtained showed its high efficiency in predicting faults and the possibility of using it as an effective computing tool to facilitate the work of the operating personnel of power enterprises.

An innovative method of fault detection in power transformers

The Bayesian classifier is a priori the optimal solution for minimizing the total error in problems of statistical pattern recognition. The article suggests using the classifier as a regular tool to increase the reliability of defect recognition in power oil-filled transformers based on the results of the analysis of gases dissolved in oil. The wide application of the Bayesian method for solving tasks of technical diagnostics of electrical equipment is limited by the problem of the multidimensional distribution of random parameters (features) and the nonlinearity of classification. The application of a generalized feature of a defect in the form of a nonlinear function of the transformer state parameters is proposed. This simultaneously reduces the dimension of the initial space of the controlled parameters and significantly improves the stochastic properties of the random distribution of the generalized feature. A special algorithm has been developed to perform statistical calculations and the procedure for recognizing the current technical condition of the transformer using the generated decision rule. The presented research results illustrate the possibility of the practical application of the developed method in the conditions of real operation of power transformers.

Techniques for Processing Experimental Data for Structural Health Monitoring of Bridges

Reliability of transport artificial structures and transit of trains at sanctioned speed should be provided with the necessary and sufficient load-bearing capacity, strength, rigidity, and stability of engineering structures.The objective of this work was to substantiate the possibility of using well-known methods for controlling the stress-strain state of structures using automated systems of structural health monitoring of bridge spans.It is extremely important regarding operation of transport artificial structures designed according to the standards of the first half of the 20th century.Under these conditions, the experimental determination of the stress-strain state of bearing structures of bridges becomes the most important component of the task of a comprehensive assessment of physical wear and tear as well as of operational reliability of the structures. Monitoring the structural health and technical condition of bridges and planning of timely measures aimed at the repair, strengthening or reconstruction of spans will extend their service life and ensure safety during operation.Maximum permissible deflections of spans under a movable temporary vertical load have been revealed since to ensure smooth movement of vehicles it is necessary to control horizontal longitudinal and transverse displacements of the top of the bridge piers, as well as vertical settlements.The paper suggests methods of interpreting data measured by inclinometers and electric strain gauges, tensiometers to use them in an automated system for monitoring the structural health of railway bridges. The method of strain measurement is described in detail in the proposed options for installing resistance strain gauges on structures to measure tensile-compression stresses and longitudinal forces due to a temporary vertical load.Monitoring the technical condition of bridge structures, using the methods for measuring deflections and deformations proposed by the authors in this article, will make it possible to assess the change in bearing capacity of the structure over the entire period of operation. The study used regulations and experience of the Russian Federation and the Republic of Kazakhstan.

Development of Dry Sand-Lime New Multicomponent Mortars into the Historical Cultural Monuments Applied on Local Raw Basis

The visual and instrumental research of the technical condition of historical cultural constructions and their stone additions, documentation of their existing damages, as well as complex development and implementation of further collapse preventing measures and construction durability ensuring measures are presented. Application of processed sand-lime complex mortars based on local raw is offered for blockage of composition cracks during the rehabilitation work taking into consideration some averaged indices of Mape Antique I, Italian “Mapey” firm, similar injection mortar orientation basic characteristics (physical and mechanical characteristics, leakage, viability) and complete laboratory detailed examination results of the component mineralogical and physical and mechanical characteristics of the substances originally used in the construction. The data on local based raw processed sand-lime construction complex mortars (blockage mortar, injection mortar) physical and mechanical characteristics, thermographic dilatometric properties dependence on composition and fastening conditions of mortars are presented

Some Evaluations on the Technical State of Metal Products and Determination of their Safe Operation Period on the Basis of Criterial Control

Over a long period of operation, under the influence of corrosion and stresses from the acting forces, metal structures lose their strength. There is a need for their periodic non-destructive testing. The development of new methods is relevant in the field of control of building metal structures, such as bridge structures, structures of building cranes and other mechanical engineering products. The applied methods should be reliable and should not require huge material and labor costs. In this work, informational relationships between acoustic characteristics and parameters of metal microstructure are established. The proposed method can be useful for specialists and experts in the field of monitoring the technical condition of metal products requiring non-destructive testing. The safety of the operated objects depends on the accuracy of the applied criteria, as well as the degree of resource saving due to the full use of the product resource.

Application and evaluation of the technical condition of composite materials in aircraft and unmanned aerial vehicles by acoustic emission method of nondestructive testing

Introduction. The paper analyzes the application of composite materials as the main determining method of reducing the mass of the airframe and an unmanned aerial vehicle. Advanced nondestructive testing methods provide assessing the technical condition of these materials, as well as determining stress concentrators on the airframe and an unmanned aerial vehicle with high accuracy in order to make a decision on the further operation of this object under control. The objective of the work was to increase the accuracy and efficiency of the assessment of crack resistance of composite materials through the acoustic emission control.Materials and Methods. This paper presents the nomenclature of composite materials used in the construction of various aircraft, including unmanned aerial vehicles. The most possible probable defects of these materials due to the influence of operational factors are presented. The applied methods of nondestructive testing of composite material and selection of the most suitable one according to specific advantages were compared. An experiment was carried out to determine the strength limits of carbon fiber using a hardware and software complex by acoustic emission method. The research results are presented in the form of drawings projected by the hardware and software complex.Results. The application of the acoustic-emission method of composite material control is described.Discussion and Conclusions. The results obtained experimentally can be used in the process of determining the strength limits of various composite materials by the acoustic emission method of nondestructive testing to assess the technical condition in mechanical engineering, shipbuilding, and aircraft construction. The paper is recommended to researchers involved in the design of aircraft and unmanned aerial vehicles.

Analysis of the condition of apartment buildings

These technical conditions of multi-apartment buildings are a huge digital array for making important management decisions both within the boundaries of individual territories of the municipality, and for planning budget expenditures within the municipality, the subject of the federation and the country as a whole. Aspects of the formation of data on apartment buildings in various information systems are considered. The basics of ensuring the reliability of the presented data are considered. It is noted in the work that for many years, during the transition from a planned economy to a market economy, the requirements of technical regulations and normative documents for the maintenance and operation of apartment buildings are not fully complied with by the operating organizations. The deadlines for replacing systems and equipment that have worked out the deadline are not met. It is noted that federal legislators and the Government of the Russian Federation have not determined a general procedure for monitoring the technical condition of apartment buildings and have not formed a general approach to assessing their technical condition, the obligation of owners of premises of apartment buildings to finance these works, their frequency has not been determined. It was revealed that the data obtained during the monitoring of the technical condition of apartment buildings combined in federal and regional information systems would be an objective marker in the formation of state and municipal programs in the field of reducing the housing stock unsuitable for living. financing of monitoring.

Analysis of damages and defects of the repair and operational unit of the compressor station

The need to maintain the technical condition of buildings with a significant service life determines the regularity of their inspection. The paper presents the analysis of the results of the inspection of the building of the repair and operational block of the compressor station. The analysis of the design documentation and the results of the measurement work showed that the construction is a one-story basementless building with dimensions of 54.62x18.74x5.9 m. The performed visual examination showed the presence of damages and defects of the third and fourth categories, which requires certain actions to eliminate them. Visual examination showed the need for instrumental examination. In particular, the need to determine the strength of brickwork and the strength of concrete in structures. The analysis of the results of the instrumental examination showed: the results of testing the wall masonry by the shock pulse method using the ONIKS 2.5 device showed that the compressive strength grade of silicate and ceramic bricks of the walls of the repair and maintenance block corresponds to M100, and the grade of masonry mortar is M50; The results of concrete testing by the non-destructive method of strength control in accordance with GOST 22690-88 with the DigiShmidt 2000 device showed that the class of concrete in terms of compressive strength in reinforced concrete slabs of the covering of the repair and operational block corresponds to B20, and the class of concrete in reinforced concrete beams of the covering corresponds to B25. The verification calculation showed that the strength of the reinforced concrete pavement of the repair and maintenance unit under the full design load acting at the time of the survey was ensured. The analysis showed that the technical condition of the maintenance and operation unit is of limited serviceability. The work provides recommendations for eliminating defects and damages.

Partial Least Squares Regression Approach in the Analysis of Damage Intensity Changes to Prefabricated RC Buildings during the Long Term of Mining Activity

This article presents the results of the analysis of the extent of damage to 138 multi-storey buildings with reinforced concrete prefabricated structure, which are located in the mining terrain of the Legnica-Głogów Copper District. These objects are residential and public utility buildings of up to 43 years old, erected in industrialized prefabricated technologies: large-block and large-panel systems. The research was based on the results of technical condition inventory carried out in 2002, 2007 and 2012. As part of the analysis, the damage intensity index wu was established for individual structural and finishing elements of the studied buildings. This index is defined on a six-point scale, which includes a detailed description of the extent of damage that corresponds to the successive degrees of intensity. As part of the research, the databases were significantly expanded and the generalized formulas of the damage intensity index wu for individual groups of buildings were verified. For this purpose, the partial least squares regression (PLSR) method was applied. Thereafter, the analysis of changes of this intensity in time was carried out and the relations between the extent of damage and the impacts of mining exploitation were examined. The approach presented in this paper and obtained research results are characterized by a high degree of utilitarianism and can be applied to increase the efficiency in the optimal maintenance management of buildings, including planning of repairs and retrofits throughout the technical life cycle of the buildings.

The material and technical condition of the outpatient polyclinic in Russian Federation: analysis of the current situation

The article analyzes the main indicators of the technical condition of buildings of outpatient medical organizations (units) in the Russian Federation for the period 2012–2019. The number of outpatient medical organizations (units) in emergency condition and requiring demolition tended to decrease from 215 units to 96 for the period from 2012 to 2017 in the Russian Federation. The number of units requiring reconstruction in the Russian Federation declined from 511 to 179 for 2012–2019. The number of units requiring major overhaul in the Russian Federation went down from 4,347 to 2,378 for the period from 2012 to 2018, and in 2019 rose sharply to 4,113. The number of units located in adapted premises increased from 6,723 to 8,126 for 2014–2019 in the Russian Federation. The number of units located in the rented area in the Russian Federation decreased from 1,443 to 1,414 for 2014–2019. The number of units with central water supply went up from 17559 to 19440 for 2012–2019 in the Russian Federation. The number of units with hot water supply in the Russian Federation increased from 13,012 to 15,124 for 2012–2019. The number of units with central heating rose from 16,893 to 17,546 for 2012–2019 in the Russian Federation. The number of units with a central sewer went up from 17,111 to 18,969 in the Russian Federation for 2012–2019. The number of units with telephone communication increased from 17,806 to 19,266 for 2012–2019 in the Russian Federation. The number of units with autonomous power supply rose from 941 to 1,227 in the Russian Federation for 2012–2019. The total number of outpatient medical organizations (units) in the study period increased by 7.9 %. The number of buildings requiring renovation and modernization between 2012 and 2018 tended to decrease. Not all indicators have a positive trend. Health care modernization is not completely structural.