scholarly journals ANALYSIS OF FACTORS INFLUENCING THE INTENSITY OF TRANSFORMER OIL AGEING IN LONG-TERM OPERATION

2021 ◽  
pp. 3-9
Author(s):  
Serhii Ponomarenko
Keyword(s):  
Organic Acids ◽  
Analysis Of Variance ◽  
Low Voltage ◽  
Operating Time ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Term Operation ◽  
Oxidative Reactions ◽  
Rate Of Increase

The results of the analysis of influence of operational factors and peculiarities of transformer design on intensity of oxidative reactions of transformer oils in the tanks of 110 kV high-voltage power transformers are presented. As a result of two-way analysis of variance it was found that with increasing operating time there is a statistically significant increase in the value of the organic acid content in the oil. At the same time the rate of increase in the organic acids content in the transformer oil, operated under different conditions, significantly differs, which indicates a significant influence of operating conditions on the intensity of oxidative reactions. The results of two-way analysis of variance also show that the effects of changes in factor levels are not additive, that is, the effect of a change in the level of influence of one factor leads to a change in the effect of the level of influence of another. In other words, the process of oil oxidation is cumulative and a certain level of organic acids in the oil can be achieved either over a longer period of operation, but with relatively 'light' operating conditions, or over a shorter period of time, but with more 'heavy' operating conditions. In order to determine the factors most affecting the intensity of oxidative reactions, an analysis of the quality of filled oil, operating time, the influence of the region, the influence of the type and nominal characteristics of transformers on 6 data sets with identical rates of oxidative reactions was carried out. The results of the analysis show that the intensity of oxidation reactions is strongly influenced by the operating time, the transformer loading factors, the consumer composition (region of Ukraine) as well as the type and quality of oils. At the same time, factors such as rated capacity, type of transformer, number of windings, and the value of rated voltage on the medium and low voltage windings do not influence the intensity of oxidation of oils. The results obtained allow the correction of the maximum permissible values of oil acidity, taking into account the factors affecting the intensity of oxidation of oils.

scholarly journals Improving the voltage quality of Abu Hummus network in Egypt

2020 ◽  
Vol 10 (5) ◽  
pp. 4458 ◽  
Author(s):  
Ibrahim A. Nassar ◽  
Mohammed Sh. Seif ◽  
Mahmoud M. ElAttar
Keyword(s):  
Transmission Lines ◽  
Low Voltage ◽  
Digital Simulation ◽  
Main Idea ◽  
Load Flow ◽  
Operating Conditions ◽  
Electrical Network ◽  
Transmission Network ◽  
Voltage Quality

In this paper the performance of the electrical network of Egypt is studied by considering a small part on the network (Abu Hummus city). The transmission network of Abu Hummus city was created for 66 kV, 11 kV, and 0.4 kV in the digital simulation and electrical network calculation (DIgSILENT power factory software) to study the voltage profiles. The load flow operational analysis was performed to obtain the voltage magnitudes at every bus bar. The voltage magnitudes in 11 kV and 0.4 kV networks were 10% to 15% less than the nominal value due to overloading off the transmission lines and the voltage magnitudes in 66 kV was within permissible limits. By using automatic tap-changing transformer or Static VAR System, the main idea of this paper is to obtain the voltage profiles at every bus bar to improve the voltage quality of the networks, so as to achieve better voltage profiles on the low voltage side without much effect on high voltage side under various operating conditions.

Pengaruh Pemberian Moringa oleifera Terhadap Kuantitas dan Kualitas Semen Sapi Peranakan Ongole

2020 ◽  
Vol 7 (2) ◽  
pp. 119
Author(s):  
Lukman Affandhy ◽  
Muchamad Luthfi ◽  
Dian Ratnawati ◽  
Frediansyah Firdaus
Keyword(s):  
Data Analysis ◽  
Analysis Of Variance ◽  
Research Method ◽  
Moringa Oleifera ◽  
The Third ◽  
Randomized Design ◽  
Leaf Powder ◽  
Completely Randomized Design ◽  
Second Period

ABSTRAK  Penelitian bertujuan untuk mengetahui pengaruh pemberian bubuk daun Moringa oleifera (MO) terhadap kuantitas dan kualitas semen sapi peranakan ongole (PO). Metode penelitian menggunakan percobaan lapang dengan rancangan acak lengkap dengan tiga perlakuan pemberian MO sebesar 0 kg/ekor/hari (P1); 0,05 kg/ekor/hari (P2) dan 0,1 kg/ekor/hari (P3). Analsis data menggunakan one way analysis of variance. Masing-masing perlakuan terdiri atas empat ekor dengan tiga periode pengamatan sebagai ulangan, yaitu periode pertama dan ketiga tanpa MO, dan periode kedua diberikan MO pada P2 dan P3. Hasil penelitian menunjukan bahwa volume dan pH semen perlakuan P1, P2 dan P3 tidak berbeda semua periode pengamatan. Motilitas massa spermatozoa P2 dan P3 periode kedua dan ketiga menunjukan nilai +++ berbeda nyata (P<0,05) dibandingkan dengan P1 (++); motilitas individu  perlakuan P1 menunjukkan nilai terendah 60,56±2,94 % (P<0,05) dibandingkan P2 dan P3 pada periode kedua dan ketiga (75,50±2,29 dan 72,50±2,34%). Konsentrasi spermatozoa P2 dan P3 periode kedua dan ketiga menunjukkan rata-rata  >1.350 juta/ml berbeda nyata (P<0,05) daripada P1 (876±152juta/ml), sedangkan total spermatozoa motil menunjukkan nilai tertinggi 5.647±829 juta/ml pada P3 periode kedua.Viabilitas spermatozoa P2 dan P3 menunjukkan nilai >88-89 % beda nyata (P<0,05) daripada P1 (<84 %) pada periode kedua dan ketiga, sedangkan nilai abnormalitas spermatozoa yang terbaik adalah P2 sebesar 4,30% pada periode kedua dan P3 sebesar 5,33% pada periode ketiga. Disimpulkan pemberian bubuk daun MO dengan dosis 0,1 kg/ekor/hari dapat memperbaiki kuantitas dan kualitas semen (viabilitas dan total spermatozoa motil) sapi pejantan PO.Kata kunci:  kuantitas dan kualitas semen, Moringa oleifera, sapi pejantan ABSTRACTThe research aimed to determine the effect of Moringa oleifera (MO) leaf powder on the quantity and quality of semen of ongole crossbreed. The research method used was a field experiment with a completely randomized design with three treatments giving MO of 0 kg/head/day (P1); 0.05 kg/head/day (P2) and 0.1 kg/head/day (P3). Each treatment consisted of four heads with three periods of observation as replications, namely the first and third periods without MO, and the second period was given MO on P2 and P3. Data analysis used a one-way analysis of variance. The results showed that the volume and pH of semen treated P1, P2, and P3 didn’t different in all observation periods. The second and third period spermatozoa mass motility of P2 and P3 showed that the value of +++ was significantly different (P<0.05) compared to P1 (++); Individual motility of P1 treatment showed the lowest value 60,56±2,94 % (P<0.05) compared to P2 and P3 in the second and third periods (75,50±2,29 and 72,50±2,34%). The second and third periods of P2 and P3 spermatozoa concentrations showed an average of >1,350 million/cc significantly different (P<0.05) than P1 (876±152 million/cc), while the total motile spermatozoa showed the highest value of 5,647±829 million/cc in the second period P3. The spermatozoa viability of P2 and P3 showed values >88-89% significantly different (P<0.05) than P1 (<84%) in the second and third periods, while the best spermatozoa abnormalities were P2 at 4.30% in the second period and P3 at 5.33% in the third period. It was concluded that the giving of MO leaf powder at a dose of 0,1 kg/head/day could improve the quantity and quality of semen (viability and total motile spermatozoa) of Ongole Crossbreed bulls. Keywords: bulls, Moringa oleifera, quantity and quality of semen

INFLUENCE OF DICARBOXYLIC ACIDS ON SOWING QUALITY OF SPRING BARLEY

1970 ◽  
pp. 22-25
Author(s):  
N. N. Loy ◽  
S. N. Gulina
Keyword(s):  
Organic Acids ◽  
Spring Barley ◽  
Dose Range ◽  
Dicarboxylic Acids ◽  
Rotary Machine ◽  
Working Solution ◽  
Negative Effect ◽  
Sprouted Seeds

The effect of presowing seed treatment on various concentrations of dicarboxylic (organic) acids on the sowing characteristics of spring barley has been studied. Seeds were treated with organic acids obtained by exposing cuttings to the radiation with a dose of 100 kGy and consequent hydrolysis, in concentrations: 1•10-7 %; 1•10-9; 1•10-11; 1•10-13 and 1•10-15 % on a laboratory rotary machine RVO-64 for one day before laying for germination. Distilled water was used for the control case. The rate of application of the working solution calculated as 10 liters / ton of seeds. Seeds were germinated in filter paper rolls in accordance with GOST 12038-84 requirements. The temperature was maintained at +24 ° C in the thermostat where the glasses with rolls were placed. For determination of germinative power and laboratory germination the sprouted seeds were evaluated after three and seven days, respectively. In laboratory experiments it was established that the treatment of barley seeds of varieties Zazersky 85, Nur and Vladimir with organic acids (OK) in different concentrations had both a stimulating and a negative effect. On the Zazersky 85 variety, in variants with acid concentrations of 1•10-9 and 1•10-11, an increase in germination energy (EP) by 2-4% and a significant decrease (by 3-4%) of laboratory germination (LV) of barley seeds were noted. On the Nur variety, the increase in EP was observed at 4% (concentration 1•10-11), LV and seed growth force (CPC) by 2-7% at a concentration of 1•10-7 and in the dose range 1•10-11 - 1•10-14 compared to the control values. On the grade of Vladimir, an increase in EP, LV, and CPC was found to increase by 1-6% at concentrations OK 1•10-7 and 1•10-13. It was shown that the treatment of seeds with acids led to an increase in the length of the germ in all studied varieties (by 3-9%) and dry biomass of 7-day-old seedlings - by 3-6%. Consequently, the treatment of seeds with a mixture of dicarboxylic acids has a stimulating effect on the sowing quality of spring barley.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

Viability of turbine blade material with a long service life

2019 ◽  
pp. 28-35
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
M. K. Chegurov
Keyword(s):  
Heat Treatment ◽  
Service Life ◽  
Yield Strength ◽  
Mechanical Characteristics ◽  
Operating Time ◽  
Structural Features ◽  
Operating Conditions ◽  
Standard Methods ◽  
Experimental Values ◽  
Plasticity Coefficient

This article deals with structural features and characteristic changes that affect the mechanical characteristics after different service life in real conditions using the example of the blades of the 4th stage of turbine GTE-45-3 with an operating time of 13,000 to 100,000 hours. To study the change in the state of the material under different operating conditions, determine the degree of influence of heat treatment on the regeneration of the microstructure, and restore the mechanical characteristics of the alloy after different periods of operation, non-standard methods were used: relaxation tests on miniature samples to determine the physical yield strength and microplasticity limit and quantitative evaluation of the plasticity coefficient of the material from experimental values of hardness, which allow us to identify the changes occurring in the microvolumes of the material and predict the performance of the product as a whole.

scholarly journals Evaporator Optimization of Refrigerator Systems Using Quality Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 555
Author(s):  
Sangkyung Na ◽  
Sanghun Song ◽  
Seunghyuk Lee ◽  
Jehwan Lee ◽  
Hyun Kim ◽  
...  
Keyword(s):  
Power Consumption ◽  
Operating Time ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Quality Analysis ◽  
Lubricating Oil ◽  
Optimal Operating ◽  
Compressor Piston ◽  
Refrigerator Temperature ◽  
Visualization Experiments

In this study, evaporator optimization, via both experimental and simulation methods was conducted. To evaluate the evaporator performance, under the optimal system, the compressor operating time and the effects of oil on the refrigerator system were studied. If the temperature of the refrigerator chamber reaches the setting value, the compressor stops working and it leads to the temperature of the refrigerator chamber slowly increasing, due to the heat transfer to the ambient. When the refrigerator temperature is out of the setting range, the compressor works again, and the refrigerator repeats this process until the end of its life. These on/off period can be controlled through the compressor piston movement. To determine the optimal compressor operating conditions, experiments of monthly power consumption were conducted under various compressor working times and the lowest power consumption conditions was determined when the compressor worked continuously. Lubricating oil, the refrigerator system, using oil, also influenced the system performance. To evaluate the effect of oil, oil eliminated and oil systems were compared based on cooling capacity and power consumption. The cooling capacity of the oil eliminated system was 2.6% higher and the power consumption was 3.6% lower than that of the oil system. After determining the optimal operating conditions of the refrigerator system, visualization experiments and simulations were conducted to decide the optimal evaporator and the conventional evaporator size can be reduced by approximately 2.9%.

scholarly journals Photoluminescence Spectroscopy Measurements for Effective Condition Assessment of Transformer Insulating Oil

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 732
Author(s):  
Abdelrahman M. Alshehawy ◽  
Diaa-Eldin A. Mansour ◽  
Mohsen Ghali ◽  
Matti Lehtonen ◽  
Mohamed M. F. Darwish
Keyword(s):  
Electronic States ◽  
Dissipation Factor ◽  
Condition Assessment ◽  
Transformer Oil ◽  
Term Operation ◽  
Pl Spectra ◽  
Insulating Oil ◽  
Vis Spectroscopy ◽  
Effective Condition ◽  
Dielectric Dissipation Factor

Condition assessment of insulating oil is crucial for the reliable long-term operation of power equipment, especially power transformers. Under thermal aging, critical degradation in oil properties, including chemical, physical, and dielectric properties, occurs due to the generation of aging byproducts. Ultraviolet-visible (UV-Vis) spectroscopy was recently proposed for the condition assessment of mineral oil. However, this absorption technique may involve all electronic states of the investigated material which typically yield a broad spectrum, and thus cannot precisely reflect the electronic structure of aged oil samples. It also cannot be implemented as an online sensor of oil degradation. In this paper, photoluminescence (PL) spectroscopy is introduced, for the first time, for effective condition assessment of insulating oil. The PL technique involves emission processes that only occur between a narrow band of electronic states that are occupied by thermalized electrons and consequently yields a spectrum that is much narrower than that of the absorption spectrum. Aged oil samples with different aging extents were prepared in the laboratory using accelerated aging tests at 120 °C, under which 1 day of laboratory aging is equivalent to approximately 1 year of aging in the field. These aged samples were then tested using PL spectroscopy with a wavelength ranging from 150 nm to 1500 nm. Two main parameters were evaluated for quantitative analysis of PL spectra: The full width at half-maximum and the enclosed area under the PL spectra. These parameters were correlated to the aging extent. In conjunction with PL spectroscopy, the aged oil samples were tested for the dielectric dissipation factor as an indication of the number of aging byproducts. Interestingly, we find a correlation between the PL spectra and the dielectric dissipation factor. The results of PL spectroscopy were compared to those of UV-Vis spectroscopy for the same samples and the parameters extracted from PL spectra were compared to the aging b-products extracted from UV-Vis spectra. Finally, the corresponding physical mechanisms were discussed considering the obtained results and the spectral shift for each spectrum. It was proved that PL spectroscopy is a promising technique for the condition assessment of insulating oil when compared to conventional transformer oil assessment measuring techniques and even to other optical absorption techniques.

Investigation of the different particle size dust releases from rigid filter candles during pulse-jet cleaning

2021 ◽  
pp. 095440622110179
Author(s):  
Xin Luan ◽  
Zhongli Ji ◽  
Longfei Liu ◽  
Ruifeng Wang
Keyword(s):  
Particle Size ◽  
Critical Role ◽  
Operating Conditions ◽  
Solid Particles ◽  
Dust Particles ◽  
Cleaning Efficiency ◽  
Term Operation ◽  
Cleaning Performance ◽  
Experimental Apparatus ◽  
Pulse Jet

Rigid filters made of ceramic or metal are widely used to remove solid particles from hot gases at temperature above 260 °C in the petrochemical and coal industries. Pulse-jet cleaning of fine dust from rigid filter candles plays a critical role in the long-term operation of these filters. In this study, an experimental apparatus was fabricated to investigate the behavior of a 2050 mm filter candle, which included monitoring the variation of pressure dynamic characteristics over time and observing the release of dust layers that allowed an analysis of the cleaning performance of ISO 12103-1 test dusts with different particle size distributions. These results showed the release behavior of these dusts could be divided into five stages: radial expansion, axial crack, flaky release, irregular disruption and secondary deposition. The cleaning performance of smaller sized dust particles was less efficient as compared with larger sized dust particles under the same operating conditions primarily because large, flaky-shaped dust aggregates formed during the first three stages were easily broken into smaller, dispersed fragments during irregular disruption that forced more particles back to the filter surface during secondary deposition. Also, a “low-pressure and long-pulse width” cleaning method improved the cleaning efficiency of the A1 ultrafine test dust from 81.4% to 95.9%.

scholarly journals A Novel Hybrid LDC Converter Topology for the Integrated On-Board Charger of Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3603
Author(s):  
Vu-Hai Nam ◽  
Duong-Van Tinh ◽  
Woojin Choi
Keyword(s):  
Low Voltage ◽  
Operating Conditions ◽  
Maximum Efficiency ◽  
Battery Charger ◽  
Forward Converter ◽  
Vehicle To Grid ◽  
Circulating Current ◽  
In Series ◽  
Converter Topology ◽  
Output Capacitor

Recently, the integrated On-Board Charger (OBC) combining an OBC converter with a Low-Voltage DC/DC Converter (LDC) has been considered to reduce the size, weight and cost of DC-DC converters in the EV system. This paper proposes a new integrated OBC converter with V2G (Vehicle-to-Grid) and auxiliary battery charge functions. In the proposed integrated OBC converter, the OBC converter is composed of a bidirectional full-bridge converter with an active clamp circuit and a hybrid LDC converter with a Phase-Shift Full-Bridge (PSFB) converter and a forward converter. ZVS for all primary switches and nearly ZCS for the lagging switches can be achieved for all the operating conditions. In the secondary side of the proposed LDC converter, an additional circuit composed of a capacitor and two diodes is employed to clamp the oscillation voltage across rectifier diodes and to eliminate the circulating current. Since the output capacitor of the forward converter is connected in series with the output capacitor of the auxiliary battery charger, the energy from the propulsion battery can be delivered to the auxiliary battery during the freewheeling interval and it helps reduce the current ripple of the output inductor, leading to a smaller volume of the output inductor. A 1 kW prototype converter is implemented to verify the performance of the proposed topology. The maximum efficiency of the proposed converter achieved by the experiments is 96%.

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