Temperature Dependence of on-Line DGA Results for Transformers through Membrane Extraction

2012 ◽  
Vol 614-615 ◽  
pp. 1163-1167 ◽  
Author(s):  
Yang Liu Li ◽  
Wen Da Wu
Keyword(s):  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Gas Sensors ◽  
Electrical Equipment ◽  
Membrane Extraction ◽  
Transformer Oil ◽  
Teflon Membrane ◽  
On Line ◽  
Incipient Fault ◽  
Transformer Insulation

Concentration detection of gases dissolved in transformer insulation oil is an effective method to diagnose incipient fault in electrical equipment. The permeation process of gases dissolved in transformer oil through extraction membrane is studied. Temperature dependence with accuracy of on-line DGA results through gases extraction with polymer membrane is analysed. An algorithm which includes temperature coefficient which can improve the accuracy of DGA results is proposed. An on-line DGA system with Teflon membrane and electrochemical gas sensors is constructed; while the results are adjust by temperature coefficient. Compared with GC results in the laboratory, the accuracy of the on-line DGA results has been improved.

scholarly journals Research and Application of Standard Oil Dispensing System for Dissolved Gases in Transformer Oil

2021 ◽  
Vol 2125 (1) ◽  
pp. 012072
Author(s):  
Yanping Li ◽  
Yong Li
Keyword(s):  
Electrical Equipment ◽  
Transformer Oil ◽  
Work Skills ◽  
Dissolved Gas ◽  
On Line ◽  
Important Means ◽  
Grid Operators ◽  
Oil Gas ◽  
Internal Potential ◽  
Gas Component

Abstract Measuring the content of dissolved gas components in transformer insulating oil by gas chromatography is an important means to judge the internal potential faults of oil filled electrical equipment in the process of operation supervision. The necessary work skills of power grid operators include the ability to detect the content of dissolved gas in transformer oil and judge the operation state of transformer. This paper introduces a preparation method and equipment of transformer standard oil. It can quickly prepare standard oils with various gas component contents. The standard oil quantity value is accurate, the data stability period is greater than 90 days, and the uncertainty is less than 5%. The equipment can be used for training and evaluation of transformer oil gas chromatographic analysis practitioners and calibration of transformer oil on-line gas chromatograph.

Silicon Fringe Sample Metrology—A Thickness Measurement Technique

2013 ◽  
Author(s):  
Mark Kimball
Keyword(s):  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Measurement Technique ◽  
Thickness Measurement ◽  
Sample Thickness ◽  
Index Of Refraction ◽  
Interference Fringes ◽  
Noncontact Method ◽  
Thickness Variations

Abstract Silicon’s index of refraction has a strong temperature coefficient. This temperature dependence can be used to aid sample thinning procedures used for backside analysis, by providing a noncontact method of measuring absolute sample thickness. It also can remove slope ambiguity while counting interference fringes (used to determine the direction and magnitude of thickness variations across a sample).

The Effect of Concentrated Light Intensity on Temperature Coefficient of the InGaP/InGaAs/Ge Triple-Junction Solar Cell

2015 ◽  
Vol 8 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Wei Zhao ◽  
Zhigang Zhou ◽  
Mengxun Chen
Keyword(s):  
Solar Cell ◽  
Light Intensity ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Triple Junction ◽  
Concentration Ratio ◽  
Crystalline Silicon ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Junction Solar Cell

Research on automatic tracking solar concentrator photovoltaic systems has gained increasing attention in developing the solar PV technology. A paraboloidal concentrator with secondary optic is developed for a three-junction GaInP/GalnAs/Ge solar cell. The concentration ratio of this system is 200 and the photovoltaic cell is cooled by the heat pipe. A detailed analysis on the temperature coefficient influence factors of triple-junction solar cell under different high concentrations (75X, 100X, 125X, 150X, 175X and 200X) has been conducted based on the dish-style concentration photovoltaic system. The results show that under high concentrated light intensity, the temperature coefficient of Voc of triple-junction solar cell is increasing as the concentration ratio increases, from -10.84 mV/°C @ 75X growth to -4.73mV/°C @ 200X. At low concentration, the temperature coefficient of Voc increases rapidly, and then increases slowly as the concentration ratio increases. The temperature dependence of η increased from -0.346%/°C @ 75X growth to - 0.103%/°C @ 200X and the temperature dependence of Pmm and FF increased from -0.125 W/°C, -0.35%/°C @ 75X growth to -0.048W/°C, -0.076%/°C @ 200X respectively. It indicated that the temperature coefficient of three-junction GaInP/GalnAs/Ge solar cell is better than that of crystalline silicon cell array under concentrating light intensity.

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.

Temperature coefficient of Young’s modulus of silver microwhiskers determined by a laser Doppler vibration measurement

2021 ◽  
pp. 2150350
Author(s):  
Yijun Jiang ◽  
Mingyuan Lu ◽  
Shiliang Wang ◽  
Han Huang
Keyword(s):  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Single Crystals ◽  
Young’S Modulus ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Young's Modulus ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Vibration Measurement

Temperature dependence of Young’s modulus of Ag microwhiskers was determined by a laser Doppler vibrometer. The Ag whiskers with diameters in sub-microns were synthesized by the use of physical vapor deposition (PVD). They have a five-fold twinned structure grown along the [1 1 0] direction. The temperature coefficient of Young’s modulus was measured to be [Formula: see text] ppm/K in the range of 300 K to 650 K. The measured values are very close to the reported values of [Formula: see text] ppm/K for bulk Ag single crystals. This finding can benefit the design of Ag-based micro/nano-electromechanical systems or micro/nano-interconnectors operated at elevated or lowered temperatures.

High performance and negative temperature coefficient of low temperature hydrogen gas sensors using palladium decorated tungsten oxide

2015 ◽  
Vol 3 (3) ◽  
pp. 1317-1324 ◽  
Author(s):  
Yanrong Wang ◽  
Bin Liu ◽  
Songhua Xiao ◽  
Han Li ◽  
Lingling Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Coefficient ◽  
Gas Sensors ◽  
High Performance ◽  
Negative Temperature Coefficient ◽  
Solvothermal Method ◽  
Negative Temperature ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Hydrogen Gas Sensors

A catalytically activated hydrogen sensor is obtained based on Pd decorated WO3 nanoplates constructed by a solvothermal method.

scholarly journals Superresolution Reconstruction of Electrical Equipment Incipient Fault

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Manran Wang ◽  
Li Guo ◽  
Jinhao Chen ◽  
Bingqi Lv ◽  
Yang Yang
Keyword(s):  
Power System ◽  
Rapid Development ◽  
Electrical Power ◽  
Electrical Equipment ◽  
Reconstruction Method ◽  
Industrial Accidents ◽  
Electrical Power System ◽  
Incipient Faults ◽  
Electrical Shocks ◽  
Incipient Fault

With the rapid development of industry and technology, the electrical power system becomes more complex and the electrical equipment becomes more diverse. Defective equipment is often the cause of industrial accidents and electrical injuries, which can result in serious injuries, such as electrocution, burns, and electrical shocks. In some cases, electrical equipment fault may result in death. However, in some special situation, some fault is very small even invisible, such as equipment aging, holes, and cracks, so the detection of these incipient faults is difficult or even impossible. These potential incipient faults become the biggest hidden danger in the electrical equipment and electricity power system. For these reasons, this paper proposes a superresolution reconstruction method for electrical equipment incipient fault to ensure complete detection in electrical equipment, which aims to guarantee the security of electrical power system operation and industry production. Experimental results show that this method can get a state-of-the-art reconstruction effect of incipient fault, so as to provide reliable fault detection of electrical power system.

Positive Temperature Coefficient of Avalanche Breakdown Observed in a-Plane 6H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 865-868
Author(s):  
Stanislav I. Soloviev ◽  
Alexey V. Vert ◽  
Jody Fronheiser ◽  
Peter M. Sandvik
Keyword(s):  
Optical Properties ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Breakdown Voltage ◽  
Avalanche Photodiodes ◽  
Positive Temperature Coefficient ◽  
Avalanche Breakdown ◽  
Positive Temperature ◽  
Electrical And Optical Properties ◽  
Positive Angle

In this work, avalanche photodiodes (APDs) were fabricated using a-plane 6H- and 4H-SiC materials to investigate their electrical and optical properties. Temperature dependence of avalanche breakdown was measured. The diode structures were fabricated with positive angle beveling and oxide passivation to ensure a uniform breakdown across the device area. Despite the apparent presence of micro-plasmas, we observed that the breakdown voltage of a-plane 6H-SiC APDs increased with temperature suggesting a positive temperature coefficient.

Sign in / Sign up

Export Citation Format

Share Document