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Power transformer fault warning combining support vector machine and improved grey wolf optimization algorithm
(2025-01-01)
Zhao, Shuzong
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Pattanadech, Norasage
To optimize the parameter setting of the support vector machine and improve the classification performance and computational efficiency of power transformer fault diagnosis, this study proposes an improved grey wolf optimization algorithm. By optimizing the global search and local optimization capabilities of the grey wolf algorithm and combining them with stacked denoising autoencoders, a new power transformer fault warning model is constructed. Firstly, the grey wolf optimization algorithm is optimized through four strategies: elite reverse learning, nonlinear control parameters, Lévy flight, and particle swarm optimization, which improve its global search and local optimization capabilities. Secondly, the stacked denoising autoencoder is utilized to extract high-level features of fault data, and the improved GWO algorithm and SVM are combined to complete fault classification. The results indicated that the proposed diagnostic model achieved a diagnostic accuracy of 0.979, a recall rate of 0.986, and an F1 value of 0.983 in benchmark performance testing. In practical applications, the average fault diagnosis accuracy of this model could reach up to 99.21%, and the average diagnosis time was only 0.08 s. The developed power transformer fault warning model can provide an efficient and reliable technical solution for fault diagnosis in the power system.
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Partial Discharge and Dissolved Gas Analysis on 22kV MV Oil-type Transformer - Case Study
(2024-01-01)
Inwanna, Woranan
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Waiwicha, Supisara
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Vanijkirati, Parada
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Monkolsatitpong, Suriya
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Chumpiboon, Komin
Detecting faults leading to potential failure of important power distributing transformers in the power system before an occurrence is an important attribute. Various inspection methods are available, however online PD and oil analysis remain the most preferred method. The methods mentioned do not require equipment shutdown. This paper introduces a case study of the 22kV transformer with online PD and DGA results indicating signs of problems in the insulation. The PD group found initially had an increase in density of signals during the three months and the magnitude shows an upward trend. DGA results found H2 and CH4 gas, the latter is a key gas indicating PD. Results show an increasing trend of almost three times as high during the latter half of the year. In addition, CO, CO2, and C2H6 gases were also found to be higher than average. Virtual inspection was conducted after the transformer was shut down. The surface is found to be uneven around the bus bar, causing high temperatures in the transformer which then impacts the insulation performance.
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Biological Insulating Liquids - Safe, Sustainable, Environmental-Friendly
(2024-01-01)
Pagger, Ernst
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Pattanadech, Norasage
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Muhr, Michael
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Tieber, Michael
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Kongdang, Peeraphong
Because of the aim for safe, sustainable, and environmentally friendly production, transmission, and distribution of electricity, the use of biological insulating liquids is increasing. This is reflected in the increasing number of suppliers of these liquids and the quantities being used in electrical equipment. Due to their chemical and physical properties, they are superior to conventional mineral oil in important areas. Due to their biological origin and the significantly lower energy input during production, they have a much lower CO<inf>2</inf> footprint compared to other insulating liquids. Insulating liquids produced by cracking fats and oils are not included in this article.
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The Behavior of Dissolved Gas in Mineral Oil with TiO2 and Three Types of Insulation Paper at 150 Degree Celsius
(2024-01-01)
Jongvilaikasem, Korraya
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Bunlaksananusorn, Chanin
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Vittayakorn, Wanwilai
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Pattanadech, Norasage
The main electrical insulation in oil-immersed transformers is liquid insulation and paper insulation. Liquid insulation is generally used mineral oil. However, improvements in the quality of liquid insulation are continually being made for better efficiency i.e. adding various additives such as inhibitors and nanoparticles. Nanoparticles are a solid substance used in research for many years. TiO<inf>2</inf> is a type of nano that is commonly used in research to increase the efficiency of mineral oil. This research experimented by preparing dry transformer oil mixed with 0.03% TiO<inf>2</inf>. The test vessels consisted of 3 main components: 1) 35 ml of MO with 0.03% TiO<inf>2</inf>, 2) 1 gram of paper with three types of insulation including pressboard, kraft, and diamond dot paper, and 3) two types of coils including copper and aluminum with size 1∗2.5 cm. The sample vessels were aged at 150 C for 72 hours in the vacuum oven. After aging, oil samples were analyzed by dissolved gas analysis (DGA). From the DGA test results, it was found that similar weights of different types of paper produced different gas-generating results.
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The Behavior of Dissolved Gas in Difference Liquid Insulation With ZnO Under Thermal Ageing Condition
(2024-01-01)
Jongvilaikasem, Korraya
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Bunlaksananusorn, Chanin
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Vittayakorn, Wanwilai
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Pattanadech, Norasage
Mineral oil is a commercial product that has been widely used as a dielectric liquid in transformers. However, alternative liquids have been developed to gradually replace mineral oil because of some better liquid insulating properties in the point of safety aspect and environmentally friendly. This paper represented the behavior of Dissolved Gas in different types of liquid insulations mixed with nanoparticles under thermal aging conditions. Various types of liquid insulation including mineral oil, natural ester, and palm oil added with a 0.03% concentration of zinc oxide (ZnO) and sorbitan mono-oleate surfactant (Span 80) underwent thermal stress aging at 90, 110, 130, and 150 degrees Celsius with 200 mbar for 72 hours in a vacuum oven. Then, the concentration of dissolved gas in the stressed samples was investigated by the Dissolved Gas Analysis (DGA) technique. From the test results, it was discovered that distinct liquid insulations and aging temperatures produced diverse dissolved gas generation behaviors. Besides, the dielectric liquid with Nanofluids or Nanofluids mixed with span 80 seems to have no different dissolved gas generation behaviors.
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Characterization of Electromagnetic Wave Propagation in Transformer for PD Detection Analysis
(2022-01-01)
Tiengthong, Thanadol
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Jaya Marindra, Adi Mahmud
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Pattanadech, Norasage
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Promwong, Sathaporn
The characterization of transformer wall effects a big problem regarding to the partial discharge, which caused substantial business losses and partial discharge analysis. Previously, there were methods of examination and evaluation using ultrasonic and acoustic waves, for this thesis saw the importance of having studied and done. Test the transmission of electromagnetic waves in a power transformer. The vector network analyzer was used to measure and record the results. A microstrip patch antenna was used to evaluate the experimental measurements on the designed transformer wall at different locations. The results obtained from the experiments will be analyzed, evaluated, and compared to the transfer function of the electromagnetic wave in the transformer. Considering the transfer function, power delay profile, and path loss, in the cases of no obstruction and obstruction from the evaluation and comparative consideration. Studies and experiments show that the data obtained measuring electromagnetic wave characteristics in transformers are guidelines in the study and analysis of partial discharges in the transformer. And primary data for the future analysis of partial discharges in the transformer.
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Dissolved Gas Behavior in Natural Ester under Corona, Surface, and Internal Discharges
(2020-10-25)
Jongvilaikasem, Korraya
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Pattanadech, Norasage
The normal operating transformers encounter various kinds of stresses such as thermal stress, electrical stress, mechanical stress, and ambient effect that can expedite the deterioration process. Partial discharge occurs normally in high voltage equipment under high electric field. For a natural-immersed transformer, partial discharge can be detected by the dissolved gas analysis technique. This paper presents the patterns of dissolved gas generation in natural ester under partial discharge conditions. Besides, the existence of acidity number is also reported. Various types of partial discharge, including corona discharge, surface discharge, and the FR3 impregnated pressboard internal discharge, were simulated. A needle-plane electrode was used to simulate corona discharge, a needle-plane electrode with the impregnated pressboard was used to simulate surface discharge, whereas the plane electrode with pressboards was used to simulate the internal discharge. Each experiment was simulated in the test vessel under 24 kV test voltage for 3000 hours. The natural ester and the pressboards were heated at 80°C for 12 hours. before filled in the test vessel. Each test vessel was contained two identical plane electrodes with a 32 mm gap spacing. The impregnated pressboard was fit-inserted between such electrodes. The high voltage electrode was subjected to 24 kV whereas another plane electrode was grounded. Then, the natural ester were sampled from the vessel after operating for 350, 1000, and 3000 hours respectively. Dissolved gas analysis of the natural ester in this work followed ASTM D3612; the acidity number of aging natural ester was also tested according to ASTM D664. From the test results, it was found that different types of partial discharges generated various patterns of dissolved gas generation. Besides, the experiment with non-impregnated pressboards couldn't survive in this condition.
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How Water Affects the Properties of Insulating Liquids
(2020-10-25)
Pagger, Ernst
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Muhr, Michael
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Pattanadech, Norasage
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Kongdang, Peeraphong
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Tieber, Michael
Water has a great influence on the properties of insulating liquids, but this influence does not always have the same impact on the insulation system. Depending on what kind of insulating liquid is used the influence can be more or less. Liquids with a higher water absorption and adsorption capacity are less susceptible to changing liquid properties compared to insulating liquids like mineral oil. This paper provides results of how properties of viscosity, refractive index, breakdown voltage and moisture equilibrium in transformer paper-liquid systems change in relation to the water content.
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Alternative Insulating Fluids - Interpretation of Test Results
(2020-09-01)
Pagger, Ernst Peter
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Muhr, Michael
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Rapp, Kevin
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Pattanadech, Norasage
In recent years, more and more transformers filled with esters have been put into operation. This is because people recognize the benefits of ester fluids in terms of their fire safety (high flash- and fire points) and environmental characteristics, judging from their biodegradability, their low CO2 footprint (only valid for natural ester) and their beneficial interactions with solid insulation, etc. Ester fluids have already found their way into various standards. For analysis and testing the same equipment and devices that are commonly used for mineral oil are used for ester liquid. The chemical- and physical behaviors of ester fluids compared to mineral oil are different. This must always be considered when interpreting test results stemming from ester fluids.
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Suitable power transformers for solar farm applications
(2015-08-17)
Khemmook, Panya
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Suwan-Ngam, Warachart
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Khomfoi, Surin
This paper presents a suitable power transformer for solar farm applications. Losses and economic value of the proposed transformer are compared to those of the standard transformer, for the application to a 1 MW solar farm, to help the solar farm owners select the best solution for their business. In this paper, a power electronics transformer called a Solid State Transformer (SST) is also proposed for the application to the solar farm because of its light weight, small size and varieties of functions. There are no core losses during no operation period which is about 15-16 hours a day.

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