scholarly journals Forecast model for estimating the service life of a diagnosed object based on the Neyman–Pearson method

2018 ◽  
Vol 216 ◽  
pp. 03011
Author(s):  
Sergey Barsukov ◽  
Sergey Pakhomov
Keyword(s):  
Service Life ◽  
Power Transformer ◽  
Impurity Content ◽  
Forecast Model ◽  
Threshold Value ◽  
Technical Condition ◽  
Transformer Oil ◽  
Average Risk ◽  
Iron Impurity ◽  
Object Based

The paper is aimed at developing a forecast model for estimating the service life of a diagnosed object based on the Neyman–Pearson method. It presents a procedure for selecting necessary and sufficient number of diagnostic indicators using the forecast model. The technique has been tested on the basis of a power transformer with a liquid dielectric. A condition-based operation strategy has been proposed for the transformer. According to this strategy, the iron impurity content in the dielectric liquid (oil) of the transformer should be measured every year of operation. Based on the forecast model, it is possible to calculate the variation of average risk (R) and a threshold value of iron impurity content in the transformer oil (k0) for each year of operation. Using these parameters, a reliable forecast model can be constructed to estimate the remaining service life of the transformer. The obtained relationships make it possible to identify a scientifically grounded stage in the service life of a diagnosed object, at which the number of measurable diagnostic indicators (indicators that are necessary for assessing the real technical condition of equipment) can be minimized.

On the effect of the periodicity of diagnostic measurements on improving the reliability of high-voltage transformers

2019 ◽  
Vol 12 (1) ◽  
pp. 18-21
Author(s):  
V. A. Tikhonov
Keyword(s):  
Service Life ◽  
High Voltage ◽  
Chromatographic Analysis ◽  
Aluminum Industry ◽  
Early Stage ◽  
Diagnostic Methods ◽  
Transformer Oil ◽  
Operating Voltage ◽  
Dissolved Gases ◽  
The Aluminum Industry

The influence of the periodicity of diagnostic measurements on the operational state of high-voltage transformers is considered. Examples of defects of switching devices of converter transformers and methods for their detection are given. The rationale for the importance of recognition of defects at an early stage of their occurrence is given. The influence of the multiplicity of overvoltages on the service life of converter transformers in the aluminum industry is investigated. Based on the analysis of the service life of converter transformers of one of the powerful aluminum plants, where 83% of converter transformers have exhausted their standard service life, it is shown that in 40% of cases it would be possible to avoid their failures, with timely detection and elimination of emerging defects. Examples of defects of OLR (on-load regulators) of converter transformers and methods for their detection are given. The importance of recognition of defects at an early stage of their occurrence is substantiated. A method for chromatographic analysis of dissolved gases in transformer oil has been developed for the qualitative determination of defects and ways to eliminate them. Examples of diagnostics of converter transformers at operating voltage and working load are given, providing the best quality operational characteristics of converter transformers. The periodicity of diagnostic measurements and the reduction of defects and failures has been substantiated. The question of diagnosing the state of the converter transformer TDNP-40000/10 at an enterprise of the aluminum industry is investigated. Currently, diagnostic methods are being developed based on chromatographic analysis of dissolved gases in transformer oil. The presented method of evaluating the operating parameters of transformers allows for the safe operation of high-voltage transformers and enables to increase the reliability of the power supply scheme of aluminum industry plants.

FURTHER CONTRIBUTION FOR EVALUATING THE AGING OF TRANSFORMER OIL OF POWER TRANSFORMER

2015 ◽  
Vol 43 (2) ◽  
pp. 211-226
Author(s):  
Sobhy S. Dessouky ◽  
Adel El Faraskoury ◽  
Sherif Ghoneim ◽  
Ahmed Haassan
Keyword(s):  
Power Transformer ◽  
Transformer Oil

scholarly journals Predicting the influence of the non-sinusoidal network mode on power transformers

2019 ◽  
Vol 114 ◽  
pp. 04005
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Service Life ◽  
Electric Power ◽  
Power Quality ◽  
Electrical Equipment ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Power Transformers ◽  
Electrical Network ◽  
Electrical Networks ◽  
Current Harmonics

The parameters of electrical network modes often do not meet the requirements of Russian GOST 32144-2013 and the guidelines of Vietnam. In the actual operating conditions while there is the non-sinusoidal mode in electrical networks voltage and current harmonics are present. Harmonics result in overheating and damage of power transformers since they cause additional active power losses. Additional losses lead to the additional heat release, accelerating the process of insulating paper, transformer oil and magnetic structure deterioration consequently shortening the service life of a power transformer. In this regard there arises a need to develop certain scientific methods that would help demonstrate that low power quality, for instance could lead to a decrease in the electrical equipment service life. Currently we see a development of automated systems for continuous monitoring of power quality indices and mode parameters of electrical networks. These systems could be supplemented by characteristics calculating programs that give out a warning upon detection of the adverse influence of voltage and current harmonics on various electrical equipment of both electric power providers and electric power consumers. A software program presented in the article may be used to predict the influence of voltage and current harmonics on power transformers.

scholarly journals Fuzzy Algorithm for Power Transformer Diagnostics

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nitin K. Dhote ◽  
Jagdish B. Helonde
Keyword(s):  
Gas Chromatography ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Power Transformer ◽  
Gas Analysis ◽  
Transformer Oil ◽  
Dissolved Gas ◽  
Inference System ◽  
Incipient Faults ◽  
The World

Dissolved gas analysis (DGA) of transformer oil has been one of the most reliable techniques to detect the incipient faults. Many conventional DGA methods have been developed to interpret DGA results obtained from gas chromatography. Although these methods are widely used in the world, they sometimes fail to diagnose, especially when DGA results fall outside conventional methods codes or when more than one fault exist in the transformer. To overcome these limitations, the fuzzy inference system (FIS) is proposed. Two hundred different cases are used to test the accuracy of various DGA methods in interpreting the transformer condition.

Research on Power Transformer Fault Forecast

2011 ◽  
Vol 204-210 ◽  
pp. 1553-1558
Author(s):  
Rui Rui Zheng ◽  
Ji Yin Zhao ◽  
Min Li ◽  
Bao Chun Wu
Keyword(s):  
Time Series ◽  
Fault Location ◽  
Power Transformer ◽  
Forecast Model ◽  
Ratio Method ◽  
Gray Model ◽  
Artificial Immune ◽  
Diagnosis Method ◽  
Type Data ◽  
Transformer Fault

To forecast power transformer fault, this paper proposed a integrated algorithm. Research found that discrete time series of power transformer dissolved gases concentration have 2 main types: the s type and the monotone increasing type. The gray verhulst model was chosen for forecasting the s type series, while the gray model predicted the monotone increasing type data. The two models combined a new integrated forecast model. The fault diagnosis method combines the improved three-ratio method and gray artificial immune algorithm, so it can diagnoses both single and multi power transformer faults, and give the fault location. Experiments show that the power transformer fault forecast algorithm is effective and reliable.

scholarly journals Влияние концентрации примеси магния на электрические свойства кристаллов LiNbO-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (10) ◽  
pp. 1566
Author(s):  
А.В. Яценко ◽  
С.В. Евдокимов ◽  
В.Ф. Шульгин ◽  
М.Н. Палатников ◽  
Н.В. Сидоров ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Absorption Spectra ◽  
Impurity Content ◽  
Threshold Value ◽  
Ir Absorption ◽  
Temperature Range ◽  
Polar Direction ◽  
Ir Absorption Spectra ◽  
Mg Content

Using the results of studying the electrical conductivity in the temperature range of ~ 295-460 K and the IR absorption spectra of a series of LiNbO3: Mg crystals, it is shown that as the Mg content in the sample increases, the mobility of H+ ions sharply decreases when moving along the polar direction. This effect is most clearly manifested in the samples of LiNbO3: Mg crystals with a high (above threshold value) impurity content.

Investigations on corrosion of aircrafts in the aspect of prolonged service life and operation driven by their technical condition

2012 ◽  
Vol 30 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Piotr Barszcz
Keyword(s):  
Service Life ◽  
Air Force ◽  
Atmospheric Corrosion ◽  
Protective Coatings ◽  
Technical Condition ◽  
Structural Components ◽  
Institute Of Technology ◽  
Corrosion Investigation ◽  
Prolonged Service ◽  
Research Studies

Research studies that are conducted by both the Air Force Institute of Technology (AFIT) and other domestic and foreign organizations indicate that investigations of corrosion phenomena present a very important factor with respect to prolongation of technical resources and operation of aircraft driven by their actual technical condition. The investigation of the corrosion degree and deterioration of protective coatings must be carried out in a systemic manner with thorough analysis of information that bring together the aircraft operation and the processes of corrosion and deterioration of protective coatings. The investigation must comprise measurements of the atmospheric corrosion in order to determine corrosive aggressiveness of the atmosphere and establish frequency and scope of corrosion inspection. Only the analysis of gathered information with its characteristics may guarantee safe operation of structural components of aircrafts according to their actual technical condition. This paper outlines the approach to corrosion investigation that is in place in AFIT.

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