Recent Progress of All Fiber Optic Current Transformers

Wu, Jianhua; Zhang, Xiaofeng

doi:10.1109/ifeea51475.2020.00036

Cited by 6 publications

(5 citation statements)

References 50 publications

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“…Thus, the final phase difference between the two circularly polarized lights is four times the Faraday phase shift. 13 After passing again through the 1/4 waveplate, they are restored to two orthogonal linearly polarized lights, which then undergo interference at the polarizer to obtain the output light. 14 This output light is coupled onto the photodetector, and converted to an electrical signal for the signal processing unit.…”

Section: Principle and Mathematical Model Of All-fiber Current Transf...mentioning

confidence: 99%

“…After propagating again along the sensing fiber in the reverse direction, the two new circularly polarized lights also experience the phase shifts caused by the nonreciprocal Faraday magneto‐optic effect. Thus, the final phase difference between the two circularly polarized lights is four times the Faraday phase shift 13 . After passing again through the 1/4 waveplate, they are restored to two orthogonal linearly polarized lights, which then undergo interference at the polarizer to obtain the output light 14 .…”

Section: Principle and Mathematical Model Of All‐fiber Current Transf...mentioning

confidence: 99%

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Online measurement of birefringence of sensing fibers in the AFOCT system

Yang,

Chen,

Chen

et al. 2024

Micro & Optical Tech Letters

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This paper presents a novel scheme to online measure the birefringence of the sensing fiber in all‐fiber optic current transformer (AFOCT) system, which monitors the current on direct current (DC) transmission lines using the Faraday magneto‐optic effect in sensing fibers. In this scheme, by purposefully varying the difference of square‐wave modulated phases via the phase modulator in the AFOCT system, different system transmittances can be obtained. On the basis of the relationship between the system transmittance and linear and circular birefringences, an online measurement scheme of both the linear and circular birefringences of the sensing fibers can be established. In this scheme, the AFOCT system is described by the transmission model based on the Jones matrices, with which the current on DC transmission lines can be measured from the phase shift caused by the Faraday effect. Then, under different square‐wave modulated phases, the system transmittance models are constructed with respect to the linear and circular birefringences of the sensing fiber. For a given sensing fiber with certain linear and circular birefringences, the specific system transmittances are determined and are the curves in space in the respective system transmittance models. Subsequently, these curves in space can be projected onto the coordinate plane composed of the linear and circular birefringence coordinate axes, where the intersection point of the projected plane curves gives the to‐be‐measured values of the linear and circular birefringences of the sensing fiber. The proposed scheme is validated by the preset linear and circular birefringences of the sensing fiber, with different linear birefringences of the polarization‐maintaining fiber. The measurement results show the values consistent with the preset ones.

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Section: Principle and Mathematical Model Of All-fiber Current Transf...mentioning

confidence: 99%

Section: Principle and Mathematical Model Of All‐fiber Current Transf...mentioning

confidence: 99%

Online measurement of birefringence of sensing fibers in the AFOCT system

Yang,

Chen,

Chen

et al. 2024

Micro & Optical Tech Letters

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“…Subsequently, the coupler is divided into two signals and converted into circularly polarized light, which enters the fiber ring in opposite directions and emits an optical signal with current information. The emitted light is then reversed through the whole structure, interfered with at the polarizer, and received by the detector [85]. As shown in the figure, this structure requires high processing and fabrication costs due to the application of two λ/4 waveplates, and its sensitivity is much lower than that of polarized AFOCSs.…”

Section: ) All-fibermentioning

confidence: 99%

High-Current Sensing Technology for Transparent Power Grids: A Review

Sun,

Huang,

Peng

2024

IEEE Open J. Ind. Electron. Soc.

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The global energy industry is moving towards a trend of green and low-carbon transformation. A transparent power grid represents a new development form under this energy transition trend, integrating the power grid with new generation information and communication technologies, exemplified by the internet. The use of micro smart sensors allows real-time monitoring of many important parameters of power systems via current, which is crucial for ensuring safe, stable, intelligent, and green power grid operation. Here, based on the development logic of current sensing technology for traditional-smarttransparent power grids, we focus our research on high-current sensing in a transparent power grid. First, we review the widely used traditional current sensing methods of shunts and Rogowski coils. More advanced optical fiber current sensing methods and microelectromechanical system current sensing chips are then introduced, which are more suitable for the smart sensing requirements of transparent power grids. In addition, we present and discuss the technical characteristics, research status, application scope, advantages and disadvantages, and future development directions of the above methods in detail. Finally, we address many essential challenges including miniaturization, integration, low power consumption, passive wireless sensing, long-range operation, and complex environmental parameters in the comprehensive intelligent and transparent sensing of current parameters in power grids. To address these challenges, we present three possible development directions: sensor improvement, development of communication and networking technologies for sensors, and advancement of intelligent and fast processing methods through communication.

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“…OCSs evaluations regarding these characteristics have not yet yielded conclusive or definitive results. This is one of the reasons why their use has not yet been disseminated, and it is the current challenge for the development of OCSs [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Measurement Uncertainty Analysis of Optical Current Sensors Used in Power Systems

Costa,

Martinez

2024

Preprint

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Optical current sensors have been developed and improved in recent decades, and their use has been widespread in power systems, including smart grids. Like any measuring instrument or system, the result of its measurements is associated with a measurement uncertainty, which quantifies its precision. This article presents a review of the main uncertainty contributions that affect the quality and performance of optical current sensors.

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Recent Progress of All Fiber Optic Current Transformers

Cited by 6 publications

References 50 publications

Online measurement of birefringence of sensing fibers in the AFOCT system

Online measurement of birefringence of sensing fibers in the AFOCT system

High-Current Sensing Technology for Transparent Power Grids: A Review

Measurement Uncertainty Analysis of Optical Current Sensors Used in Power Systems

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