During the last few years, there has been a growing interest in the topic of using natural or synthetic esters as an alternative to mineral oils in oil transformers due to the easier way to obtain them and their abili...
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This paper presents a practical laboratory for student education purpose in Distributed control Systems, with focus on applications for high voltage transmission substations. The monitoring, control and protection par...
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As the Industrial Internet of Things evolves, ever more data acquisition devices are integrated inside factories, silos, agriculture facilities, industrial facilities, cars and many other applications. One of the most...
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The paper deals with the methodology of creation of sequential control system programs in the language of function block diagrams (FBD). After analyzing basic blocks of the sequential functions chart (SFC) language, t...
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The paper deals with the methodology of creation of sequential control system programs in the language of function block diagrams (FBD). After analyzing basic blocks of the sequential functions chart (SFC) language, the form of state block and implementation of branching or connecting paths of sequences are formulated using the FBD language. It is a simplification of the application of the SFC language. Our method of creating the sequential system ensures a compact form of the final program and is particularly useful for small PLC controllers. The method is illustrated by example of the simple sequential control system.
Differential Ant Stigmergy Algorithm (DASA) is a recent meta-heuristic method which represents an adaptation of Ant Colony Optimization (ACO) to continuous optimization problems. Other adaptations of ACO to continuous...
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The high-performance length cutting lines of the strip use the Flying Shear, a mechanism that is moved by a vector controlled three-phase asynchronous motor. The operating principle of the cutting line involves a comp...
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The subject matter of this paper refers to vibroacoustic measurements of high power transformers. The evaluation method of the transformer technical condition, based on the measurements of mechanical vibrations of its...
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ISBN:
(纸本)9781627480000
The subject matter of this paper refers to vibroacoustic measurements of high power transformers. The evaluation method of the transformer technical condition, based on the measurements of mechanical vibrations of its tub, is characterized. The elements of the measuring set-up, which were used during the registration of the signals coming from the core and winding vibrations of a given transformer unit, transferred by the tub, are presented. Based on the criterion values of the vibroacoustic parameters measured: root-mean-square value of the vibration acceleration and the vibration spectrum amplitude in the frequency range from 0 to 3000 Hz, the evaluation of the technical condition of the power appliance under study was carried out.
The paper presents the measurement results of the noise level of a power transformer. The noise sources occurring in the transformer are presented, and the method applied and the measuring tools used are characterized...
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ISBN:
(纸本)9781627480000
The paper presents the measurement results of the noise level of a power transformer. The noise sources occurring in the transformer are presented, and the method applied and the measuring tools used are characterized. The measurements were taken in 29 points located around the transformer. The evaluation of noise was carried out based on the revised coefficient of the acoustic pressure level. The research work results presented enable the evaluation of the influence of the noise of the unit under study on its environment and make it easier to diagnose the degrees of wear of the fans installed in transformer coolers.
The paper will present the wavelet analysis results using continuous and discrete wavelet transforms of vibrations of a power transformer tub installed on the block of a conventional, thermal condensation power statio...
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ISBN:
(纸本)9781627480000
The paper will present the wavelet analysis results using continuous and discrete wavelet transforms of vibrations of a power transformer tub installed on the block of a conventional, thermal condensation power station. The research tests were carried out during a regular transformer operation in industrial conditions. The measurements were taken from the point of view of the evaluation of the influence of the vibrations registered on the analysis results of the acoustic emission signals generated by partial discharges that can occur in paper-oil insulation systems of power transformers. Moreover, the analyses carried out were supplemented with the research results obtained in laboratory conditions during the measurements taken in the high-voltage testing station of high-voltage power appliances. The influence of the loosened screws fastening the lid of the transformer tub on the time-frequency analysis results obtained of the vibrations registered was investigated. Moreover, the range of the research work carried out referred to the evaluation of the influence of the changes of the pressure force of the metal plates forming the transformer core on the vibration measurement results were obtained. In summary, the evaluation of usefulness was presented and the range of the time-frequency analysis application possibilities, and especially wavelet transforms, in diagnostics of power transformers using the acoustic methods was characterized.
The paper presents research results of electrokinetic zeta potential that exists in the electrical double layer on the border of the solid and liquid phases. For zeta potential examination, samples in the colloid form...
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The paper presents research results of electrokinetic zeta potential that exists in the electrical double layer on the border of the solid and liquid phases. For zeta potential examination, samples in the colloid form were used, the continuous (dispersing) phase of which was constituted by dielectric liquid mixtures formed on the base of simple hydrocarbons (hexane, cyclohexane, toluene), and the solid (dispersed) phase was constituted by materials in a disintegrated form (aluminum, copper, steatite, Al-70). The measurements were taken with Zetasizer 2000 - by Malvern Instruments (UK). Volume density of charge qw on the border of the solid and liquid phases, responsible for generation of electrostatic charges, was determined based on the measured zeta potential and physicochemical properties of the liquids under study.
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