Effects of Degraded Optical Fiber Sheaths on Thermal Aging Characteristics of Transformer Oil

Liu, Yunpeng; Jiang, Shuo; Fan, Xiaozhou; Yuan, Tian

doi:10.3390/app8081401

Cited by 16 publications

(8 citation statements)

References 20 publications

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“…The fiber sheath material is generally an organic polymer, and its stability is crucial for the safe operation of the transformer and the reliability of the fiber sensing. Based on our previous research [21][22][23], ethylene tetrafluoroethylene, ethylene-four fluoroethylene copolymer (ETFE) sheath, which can withstand temperatures up to 150 • C, is chemically stable, has no obvious effect on the overall insulation performance of oil, and is suitable for use in oil-immersed transformers.…”

Section: Calibration Of Fiber Strain and Temperature Coefficientmentioning

confidence: 99%

Transformer Winding Deformation Detection Based on BOTDR and ROTDR

Gao

Liu

et al. 2020

Sensors

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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.

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Section: Calibration Of Fiber Strain and Temperature Coefficientmentioning

confidence: 99%

Transformer Winding Deformation Detection Based on BOTDR and ROTDR

Gao

Liu

et al. 2020

Sensors

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“…In order to study the influence of aging fiber sheaths on transformer oil, Liu et al [114] used two types of special optical fibers, one with thermoplastic polyester elastomer (TPEE) and the other poly tetra fluoroethylene (PTFE), as sheaths were subjected to thermally accelerated aging in transformer oil at 130 • C. Compared with TPEE on different parameters, such as DDF, DP, acidity, water content, breakdown voltage, and volume resistivity, PTFE showed good behavior on oil ageing. Therefore, it was suggested to use a fiber with a jacket material of PTFE built into the transformer.…”

Section: Oil Ageing Assessmentmentioning

confidence: 99%

Review of Fiber Optic Diagnostic Techniques for Power Transformers

N’cho

Fofana

2020

Energies

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Diagnostic and condition monitoring of power transformers are key actions to guarantee their safe operation. The subsequent benefits include reduced service interruptions and economic losses associated with their unavailability. Conventional test methods developed for the condition assessment of power transformers have certain limitations. To overcome such problems, fiber optic-based sensors for monitoring the condition of transformers have been developed. Flawlessly built-up fiber optic-based sensors provide online and offline assessment of various parameters like temperature, moisture, partial discharges, gas analyses, vibration, winding deformation, and oil levels, which are based on different sensing principles. In this paper a variety and assessment of different fiber optic-based diagnostic techniques for monitoring power transformers are discussed. It includes significant tutorial elements as well as some analyses.

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“…To ensure that the optical fiber works stably under the high temperature environment of transformer and has good compatibility with transformer oil, in our former series work [ 32 ], the safety test was performed through the accelerated thermal aging method (130 °C for 576 h). Tetrafluoroethylene (ETFE) and polyimide (PI) was finally selected as the optical fiber sheath and coating layer material due to their stable performance after the long-term aging process in the transformer oil.…”

Section: Fabrication and Platform Setupmentioning

confidence: 99%

Global Temperature Sensing for an Operating Power Transformer Based on Raman Scattering

Liu

et al. 2020

Sensors

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Traditional monitoring methods cannot obtain the overall thermal information for power transformers. To solve this problem, a distributed fiber optic sensor (DFOS) was creatively applied inside an operating 35 kV power transformer by highly integrating with the electromagnetic wires. Then, the transformer prototype with totally global sensing capability was successfully developed and it was qualified for power grid application through the strict ex-factory tests. The as designed optical fiber sensor works stably all the time with a temperature accuracy of ±0.2 °C and spatial positioning accuracy of 0.8 m. Based on the obtained internal temperature distribution, Gaussian convolution was further applied for the signal processing and hereby, the hotspots for all the windings and iron cores could be accurately traced. The hottest points were located at 89.1% (55 °C) of the high voltage winding height and 89.7% (77.5 °C) of the low voltage winding height. The actual precise hotspot location corrected the traditional cognition on the transformer windings and it would serve as an essential reference for the manufactures. This new nondestructive internal sensing and condition monitoring method also exhibits a promising future for the DFOS applying in the high-voltage electrical apparatus industry.

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Effects of Degraded Optical Fiber Sheaths on Thermal Aging Characteristics of Transformer Oil

Cited by 16 publications

References 20 publications

Transformer Winding Deformation Detection Based on BOTDR and ROTDR

Transformer Winding Deformation Detection Based on BOTDR and ROTDR

Review of Fiber Optic Diagnostic Techniques for Power Transformers

Global Temperature Sensing for an Operating Power Transformer Based on Raman Scattering

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