Monitoring Method of Stray Current in Coal Mine on Optical Fiber Sensing Technique

2010 ◽  
Vol 43 ◽  
pp. 457-462 ◽  
Author(s):  
Li Hua Cai ◽  
Wei Li ◽  
Hai Feng Fang
Keyword(s):  
Optical Fiber ◽  
Coal Mine ◽  
Polarization State ◽  
Polarized Light ◽  
Linear Birefringence ◽  
Stray Current ◽  
Monitoring Method ◽  
Current Sensing ◽  
Fiber Sensing ◽  
Current Monitoring

In this work a novel monitoring method was developed to measure the underground stray current in coal mine with fiber current sensing technique. According to the theory of optical fiber current sensor based on Faraday magneto-optic effect, a fiber sensing system was designed and the relative experiments with current generator simulating stray current were completed. The results indicate that the measurement was influenced by birefringence and temperature change. The sensing heads with high cylindrical birefringence optical fiber had a good suppressing effect on linear birefringence and the polarization state of polarized light was also more stable than that with low birefringence optical fiber. The fiber current sensing method is doable in underground stray current monitoring system in coal mine.

scholarly journals The Characterization Pattern of Overburden Deformation with Distributed Optical Fiber Sensing: An Analogue Model Test and Extensional Analysis

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7215
Author(s):  
Qiang Yuan ◽  
Jing Chai ◽  
Yiwei Ren ◽  
Yongliang Liu
Keyword(s):  
Optical Fiber ◽  
Model Test ◽  
Optical Fiber Sensor ◽  
Analogue Model ◽  
Monitoring Method ◽  
Fiber Sensing ◽  
Time Space ◽  
Characterization Model ◽  
Optical Fiber Sensing ◽  
Distributed Optical Fiber

The evolution of overburden deformation is crucial for safety and environmental efficiency and its monitoring is becoming a key scientific issue. The use of an optical fiber sensor (OFS) for mining engineering is now receiving praise by virtue of its distinct abilities of distribution, high accuracy, and anti-interference measurement. Nevertheless, the dynamic response of OFS monitoring on overburden deformation still needs to be characterized in detail. This paper analyzed the characterization pattern of overburden deformation based on distributed optical fiber sensing (DOFS) by means of an analogue model test. Then, we discuss the influence of rules of optical fiber embedding on a model test in a numerical simulation. The results show that the DOFS monitoring demonstrates the time-space evolution of overburden deformation and the development of three horizontal areas and three vertical zones. A standardization DOFS characterization model is proposed to expound the characterization mechanism of the overburden structure zoning process; the influence of optical fiber embedding on rock displacement in the model test is revealed, and it is found that the displacement error will increase sharply when the fiber diameter is larger than 2 mm. These findings could provide an effective solution for a monitoring method in intelligent mining from the perspective of a theoretical basis and technological system.

Reflective Detection Method of Partial Discharge Using Optical Fiber Sensor

2020 ◽  
Vol 41 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Gaifang Xin ◽  
Jun Zhu ◽  
Chengming Luo ◽  
Wei Li
Keyword(s):  
Optical Fiber ◽  
Partial Discharge ◽  
Optical Fiber Sensor ◽  
Optical Path ◽  
Path Model ◽  
Current Sensor ◽  
Linear Birefringence ◽  
Current Sensing ◽  
Sensing System ◽  
Fiber Optical

AbstractAiming at the characteristic of small amplitude of partial discharge current signal, all-optical fiber current sensing system is designed. Two kinds of optical fiber current sensor structures are proposed, which are linear and reflective. The optical path systems of two kinds of fiber optical current sensor are modeled based on Jones matrix. In addition, the output sensitivities of two structures are compared. The results indicate that the sensitivity of the two current sensor structures can be improved, and the output sensitivity of the reflective fiber optical current sensor is twice as high as that of the linear sensor. At the same time, the complete optical path model of optical fiber sensing system is established under the influence of fiber birefringence errors. Finally, the birefringence errors of sensing fiber are simulated. It is concluded that the reflective fiber optical current sensor can suppress the influence of linear birefringence on the accuracy of the sensing system by introducing a large amount of circular birefringence in the sensing fiber.

scholarly journals Early warning platform and its potential for non-coal mine goaf monitoring based on an optical fiber sensing network

2018 ◽  
Vol 1065 ◽  
pp. 252018 ◽  
Author(s):  
Zengrong Sun ◽  
Tongyu Liu ◽  
Guangdong Song ◽  
Binxin Hu ◽  
Long Jiang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Coal Mine ◽  
Early Warning ◽  
Fiber Sensing ◽  
Optical Fiber Sensing

scholarly journals Improved NEPA Substations On-Line Monitoring Technology Using Optical Fiber Sensors

2003 ◽  
Vol 2 (1) ◽  
Author(s):  
M Omidiora
Keyword(s):  
Optical Fiber ◽  
Condition Monitoring ◽  
Optical Fiber Sensors ◽  
Monitoring Method ◽  
Future Directions ◽  
Fiber Sensors ◽  
The Arts ◽  
On Line ◽  
Substation Equipment ◽  
Current Monitoring

Condition monitoring of power substations is a significant issue for the National Electric Power Authority (NEPA) of Nigeria. Current methods for monitoring the condition of high voltage equipment are time consuming and often inaccurate, therefore causing catastrophic damage to the substation equipment. Recent research has demonstrated the efficacy of employing optical fiber sensors in condition monitoring of substation equipment. These sensors enhance the current monitoring method and facilitate faster responses to equipment problems. This paper briefly reviews the state of the arts, but is primarily devoted to a discussion of the new approach and future directions in condition monitoring of NEPA substation equipment.

Research on Spectrum Domain White Light Interference Demodulation Mechanism of the Optical Fiber Sensing Coal Gas

2012 ◽  
Vol 229-231 ◽  
pp. 1132-1135
Author(s):  
Meng Ran Zhou ◽  
Dong Yue Ling ◽  
Ying Liang Ye
Keyword(s):  
Optical Fiber ◽  
Coal Mine ◽  
Good Prospect ◽  
Gas Monitoring ◽  
Gas Concentration ◽  
Fiber Sensing ◽  
Light Interference ◽  
Reflected Light ◽  
Safety Production ◽  
Optical Fiber Sensing

In our country, as the great threat caused by gas explosion or gas accident to the safety in coal mine production, the development of gas monitoring system is key to preventing accidents beforehand.. Putted into interferometer, the amplitude and the intensity of the incident ray carrying the information of gas concentration are divided many times by reflection and transmission, which results in many parallel beams in the form of the reflected light and the transmitted light. The concentration of the gas can be obtained by testing the light intensity signal . The experiment results show that an accurate measurement result which is capable for the gas concentration test in underground abominable conditions can be got by this mean. Particularly, based on multiplexing technique of optical fiber sensing, it is easy to build a sensor network. This method has an important significance and a good prospect of application and extension for gas monitoring and safety production in the coal mine.

On-site monitoring of bearing failure in composite bolted joints using built-in eddy current sensing film

2020 ◽  
pp. 002199832097973
Author(s):  
Qijian Liu ◽  
Hu Sun ◽  
Yuan Chai ◽  
Jianjian Zhu ◽  
Tao Wang ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Eddy Current ◽  
Failure Modes ◽  
Bolted Joints ◽  
Bearing Failure ◽  
Monitoring Method ◽  
Current Sensing ◽  
Site Monitoring ◽  
Array Sensing ◽  
Bearing Damage

Bearing damage is one of the common failure modes in composite bolted joints. This paper describes the development of an on-site monitoring method based on eddy current (EC) sensing film to monitor the bearing damage in carbon fiber reinforced plastic (CFRP) single-lap bolted joints under tensile testing. Configuration design and operating principles of EC array sensing film are demonstrated. A series of numerical simulations are conducted to analyze the variation of EC when the bearing failure occurs around the bolt hole. The results of damage detection in the horizontal direction and through the thickness direction in the bolt hole with different exciting current directions are presented by the finite element method (FEM). Experiments are performed to prove the feasibility of the proposed EC array sensing film when the bearing failure occurs in CFRP single-lap bolted joints. The results of numerical simulations and experiments indicate that bearing failure can be detected according to the variation of EC in the test specimen.

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