scholarly journals Development of an Online Detection Setup for Dissolved Gas in Transformer Insulating Oil

2021 ◽  
Vol 11 (24) ◽  
pp. 12149
Author(s):  
Yang Chen ◽  
Zhentao Wang ◽  
Zhao Li ◽  
Hongquan Zheng ◽  
Jingmin Dai
Keyword(s):  
Gas Separation ◽  
Optical System ◽  
Near Infrared ◽  
Low Frequency ◽  
Tunable Diode Laser ◽  
Separation System ◽  
Online Detection ◽  
Dissolved Gas ◽  
Insulating Oil ◽  
Oil Gas

The type and concentration of dissolved gases in transformer insulating oil are used to assess transformer conditions. In this paper, an online detection setup for measuring the concentration of multicomponent gases dissolved in transformer insulating oil is developed, which consists of an oil-gas separation system and an optical system for acquiring the transformer status in real time. The oil-gas separation system uses low pressure, constant temperature, and low-frequency stirring as working conditions for degassing large-volume oil samples based on modified headspace degassing. The optical system uses tunable diode laser absorption spectroscopy (TDLAS) to determine the gas concentration. Six target gases (methane, ethylene, ethane, acetylene, carbon monoxide, and carbon dioxide) were detected by three near-infrared lasers (1569, 1684, and 1532 nm). The stability of the optical system was improved by the common optical path formed by time-division multiplexing (TDM) technology. The calibration experiments show that the second harmonics and the concentrations of the six gases are linear. A comparison experiment with gas chromatography (GC) demonstrates that the error of acetylene reaches the nL/L level, while the other gases reach the μL/L level. The data conforms to the power industry testing standards, and the state of the transformer is analyzed by the detected six characteristic gases. The setup provides an effective basis for the online detection of dissolved gas in transformer insulating oil.

Research on the Oil-Gas Permeability of Mixed Hollow Fiber Membrane Made by PTFE and PHFP

2011 ◽  
Vol 194-196 ◽  
pp. 2480-2486 ◽  
Author(s):  
Wei Gen Chen ◽  
Mai Hao
Keyword(s):  
Gas Separation ◽  
Hollow Fiber ◽  
Gas Permeability ◽  
Hollow Fiber Membrane ◽  
Transformer Oil ◽  
Fiber Membrane ◽  
Dissolved Gas ◽  
Test Platform ◽  
On Line ◽  
Oil Gas

Power transformer on-line monitoring on dissolved gas in oil is one of the effective and technical means to achieve the transformer state detection and fault diagnosis, and oil-gas permeability is one of the core technologies to implement transformer on-line monitoring. The traditional methods of oil-gas separation such as vacuum method and mechanical oscillation method were unable to satisfy the requirements of transformer on-line monitoring; and the methods which were used commonly in recent years, like dynamic headspace separation, corrugated tube, carrier gas elution etc, have a high rate of gas-separation and have already been used in some on-line monitoring products. However, the problems still exist: easy formation of oil pollution, so the oil can not be recycled and the device structure is relatively complex. This paper based on the separation principle of polymer membrane, proposes mixed hollow fiber membrane made by polytetrafluoroethylene (PTFE) and polyhexafluoropropylene (PHFP), and designs an oil-gas separation test platform formed by the storage tank, oil-gas permeability tank, temperature controller and gas chromatographic analyzer etc, does laboratory research on the oil-gas permeability of the mixed hollow fiber membrane at different temperatures. The results show that, the permeability of the mixed hollow fiber membrane is obviously better than the commonly used single fluoride film or rubber film, seven fault gases H2, CO, CO2, CH4, C2H6, C2H4, and C2H2 can be separated efficiently form transformer oil within 24 hours. More to the point, the equilibrium time is short, the gas permeability is high and the test platform structure is simple, all of these advantages provide a strong guarantee for the development of on-line monitoring technology on dissolved gas in transformer oil.

Design of Near Infrared Continuous Zoom Optical System

2020 ◽  
Author(s):  
Ma Zi-xuan ◽  
Li Xu-yang ◽  
Ren Zhi-guang ◽  
Chu Nan-qing
Keyword(s):  
Optical System ◽  
Near Infrared

Online detection and quantification of ergot bodies in cereals using near infrared hyperspectral imaging

2012 ◽  
Vol 29 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Ph. Vermeulen ◽  
J.A. Fernández Pierna ◽  
H.P. van Egmond ◽  
P. Dardenne ◽  
V. Baeten
Keyword(s):  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Online Detection ◽  
Detection And Quantification

Low-frequency multiplex CARS microscopy with a high-repetition near-infrared supercontinuum laser

2021 ◽  
Author(s):  
Yusuke Arashida ◽  
Atsushi Taninaka ◽  
Takayuki Ochiai ◽  
Hiroyuki Mogi ◽  
Shoji YOSHIDA ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
High Sensitivity ◽  
High Repetition ◽  
Spectrum Shaping ◽  
Crystal Phase Transition ◽  
Wavenumber Region ◽  
Anti Stokes

Abstract We have developed a multiplex Coherent anti-Stokes Raman scattering (CARS) microscope effective for low-wavenumber measurement by combining a high-repetition supercontinuum light source of 1064 nm and an infrared high-sensitivity InGaAs diode array. This system could observe the low-wavenumber region down to 55 cm-1 with high sensitivity. In addition, using spectrum shaping and spectrum modulation techniques, we simultaneously realized a wide bandwidth (<1800 cm-1), high wavenumber resolution (9 cm-1), high efficiency, and increasing signal to noise ratio by reducing the effect of the background shape in low-wavenumber region. Spatial variation of a sulfur crystal phase transition with metastable states was visualized.

Evaluation of fNIRS Signal Components Elicited by Cognitive and Hypercapnic Stimuli

2021 ◽  
Author(s):  
Pratusha Reddy ◽  
Meltem Izzetoglu ◽  
Patricia Shewokis ◽  
Michael Sangobowale ◽  
Ramon Diaz-Arrastia ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared ◽  
Low Frequency ◽  
Hemispheric Differences ◽  
Functional Versus ◽  
Functional Near Infrared Spectroscopy ◽  
Global Response ◽  
Very Low Frequency ◽  
Systemic Responses ◽  
And Task

Abstract Functional near infrared spectroscopy (fNIRS) measurements are confounded by signal components originating from multiple physiological causes, whose activities may vary temporally and spatially (across tissue layers, and regions of the cortex). Furthermore, the stimuli can induce evoked effects, which may lead to over or underestimation of the actual effect of interest. Here, we conducted a temporal, spectral, and spatial analysis of fNIRS signals collected during cognitive and hypercapnic stimuli to characterize effects of functional versus systemic responses. We utilized wavelet analysis to discriminate physiological causes and employed long and short source-detector separation (SDS) channels to differentiate tissue layers. Multi-channel measures were analyzed further to distinguish hemispheric differences. The results highlight cardiac, respiratory, myogenic, and very low frequency (VLF) activities within fNIRS signals. Regardless of stimuli, activity within VLF band had the largest contribution to the overall signal. The systemic activities dominated the measurements from the short SDS channels during cognitive stimulus, but not hypercapnic stimulus. Importantly, results indicate that characteristics of fNIRS signals vary with type of the stimuli administered as cognitive stimulus elicited variable responses between hemispheres in VLF band and task-evoked temporal effect in VLF, myogenic and respiratory bands, while hypercapnic stimulus induced a global response across both hemispheres.

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.

Sign in / Sign up

Export Citation Format

Share Document