scholarly journals Transformer Winding Deformation Detection Based on BOTDR and ROTDR

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2062 ◽  
Author(s):  
Shuguo Gao ◽  
Yunpeng Liu ◽  
Huan Li ◽  
Lu Sun ◽  
Hongliang Liu ◽  
...  
Keyword(s):  
Time Domain ◽  
Measurement Accuracy ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Test Results ◽  
Transformer Winding ◽  
Winding Deformation ◽  
Distributed Measurement ◽  
Optical Time ◽  
Distributed Optical Fiber

In order to realize distributed measurement of transformer winding temperature and deformation, a transformer winding modification scheme with a built-in distributed optical fiber was designed. By laying a single-mode fiber and a multi-mode fiber on the transformer winding, the Brillouin optical time domain reflection technique (BOTDR) and the Raman optical time domain reflection technique (ROTDR) are used to measure the strain and temperature of the winding to complete the more accurate winding deformation detection. The accuracy of strain and temperature sensing of this scheme was verified by simulation. Then, according to the scheme, a winding model was actually wound, and the deformation and temperature rise tests were carried out. The test results show that this scheme can not only realize the deformation detection and positioning of the winding, but can also realize the measurement of the winding temperature; the temperature measurement accuracy reached ±0.5 °C, the strain measurement accuracy was 200 με, and spatial resolution was up to 5 m. In this experiment, the deformation location with the precision of 2 turns was realized on the experimental winding.

scholarly journals Enhancement of Distributed Temperature Sensitivity Using Al-Coated Fiber in OFDR

2018 ◽  
Author(s):  
Yong-seok Kwon ◽  
Khurram Naeem ◽  
Min Yong Jeon ◽  
Il-Bum Kwon
Keyword(s):  
Temperature Sensitivity ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Coated Fiber ◽  
Rayleigh Backscattering ◽  
Enhanced Sensitivity ◽  
Optical Frequency Domain Reflectometry ◽  
Frequency Domain Reflectometry ◽  
Distributed Measurement ◽  
Distributed Optical Fiber

We present a distributed optical-fiber temperature sensor with enhanced sensitivity based on an Al-coated fiber using the Rayleigh backscattering spectra (RBS) shift in optical frequency-domain reflectometry (OFDR). The Al-coated sensing fiber with a higher thermal expansion coefficient compared to silica produces a strain-coupled shift in the RBS under an increase in temperature. This effect leads to an enhanced temperature sensitivity of the distributed measurement scheme. Our results revealed that the temperature sensitivity obtained using the Al-coated fiber in OFDR was ~56% higher relative to that of a single-mode fiber. Moreover, the minimum measurable temperature recorded was 1 °C with a spatial resolution of 5 cm.

scholarly journals Distributed Fiber Birefringence Measurement Using Pulse-Compression Φ-OTDR

2020 ◽  
Author(s):  
Yongxiang Chen ◽  
Yun Fu ◽  
Ji Xiong ◽  
Zinan Wang
Keyword(s):  
Spatial Resolution ◽  
Pulse Compression ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Time Domain Reflectometry ◽  
Coherent Detection ◽  
Compression Phase ◽  
Optical Time Domain Reflectometry ◽  
Fiber Birefringence ◽  
Optical Time

Abstract In this paper, a novel birefringence measurement method through the Rayleigh backscattered lightwave within single-mode fiber is proposed, using a single chirped-pulse with arbitrary state of polarization. Numerical analysis is carried out in detail, then pulse-compression phase-sensitive optical time domain reflectometry (PC-Φ-OTDR) with polarization-diverse coherent detection is employed to verify this method. A 2km spun single-mode fiber is tested with 8.6 cm spatial resolution, and the average birefringence of the fiber under test is measured as 0.234rad/m, which is consistent with previous literatures about single-mode fiber. Moreover, the relationship between the measured birefringence and the spatial resolution is also studied for the first time, and the results show that spatial resolution is crucial for fiber birefringence measurement.

scholarly journals Improved Training Sequence Channel Estimation Scheme in 16QAM MB-OFDM UWBoF System

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Changqing Xiang ◽  
Xi Yang ◽  
Xuan Zhou ◽  
Xiaojun Zhu ◽  
Jincan Xu ◽  
...  
Keyword(s):  
Channel Estimation ◽  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Single Mode ◽  
Training Sequence ◽  
Single Mode Fiber ◽  
Frequency Division ◽  
Training Sequences ◽  
Estimation Scheme ◽  
Simulation Results

In this paper, an improved channel estimation scheme based on time-domain orthogonal gray complementary training sequence (Golay TS) is proposed to resist subcarrier mutual beat interference in 16-quadrature amplitude modulation multiband orthogonal-frequency-division-multiplexing ultrawide band over fiber (16QAM MB-OFDM UWBoF) systems. The simulation results showed that the performance of system with the improved Golay TS channel estimation scheme was improved by about 1 dB compared with the traditional Golay TS channel estimation scheme, at a bit error rate (BER) of 3.8 × 10−3 after 70 km standard single mode fiber (SSMF) transmission. At the same time, the synchronization and channel estimation performance of Golay TS and the selected frequency-domain orthogonal training sequences (TSs) were compared. The simulation results showed that the performance of system with the TSs channel estimation was improved by about 2.7 dB compared with the improved Golay TS channel estimation.

Self-detecting optical-time-domain reflectometer for single-mode fibers

1985 ◽  
Vol 10 (3) ◽  
pp. 157 ◽  
Author(s):  
Masataka Nakazawa ◽  
Masahiro Ikeda ◽  
Takashi Nakashima ◽  
Shigeyuki Seikai
Keyword(s):  
Time Domain ◽  
Single Mode ◽  
Optical Time Domain Reflectometer ◽  
Optical Time ◽  
Time Domain Reflectometer

The On-Line Monitoring of the Winding Deformation of Transformer Based on the Improved Ultrasonic Ranging Method

2014 ◽  
Vol 672-674 ◽  
pp. 1159-1162 ◽  
Author(s):  
Wei Jia Liu ◽  
Xin Wang ◽  
Yi Hui Zheng ◽  
Li Xue Li ◽  
Yong Bo Lang ◽  
...  
Keyword(s):  
Transformer Oil ◽  
Practical Significance ◽  
Test Results ◽  
Signal Attenuation ◽  
Ultrasonic Ranging ◽  
Transformer Winding ◽  
On Line ◽  
Working Principle ◽  
Winding Deformation ◽  
The Impact

The assessment of the winding deformation of transformer has a certain practical significance. In this paper, an Improved Ultrasonic Ranging (IUR) method is proposed to assess the winding deformation of transformer. Firstly, the basic principle of winding deformation detection using ultrasonic and the working principle of detection device are discussed. Secondly, the impact of the factors such as transformer oil temperature and echo signal attenuation on the test results is analyzed. Then, a new IUR method is composed, which can realize the on-line monitoring of transformer winding deformation. Finally, an assessment equipment of transformer winding deformation based on the online monitoring is developed, and a prototype is used to test the transformer mode, proving that this method is feasible.

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