scholarly journals Performance Evaluation of Optical Fiber Current Transformer based Over-current Protection

2019 ◽  
Vol 8 (1) ◽  
pp. 40-47
Author(s):  
Sulieman Eldoud Bashir Ahmed
Keyword(s):  
Optical Fiber ◽  
Calibration Procedure ◽  
Current Transformer ◽  
Superior Performance ◽  
System Protection ◽  
Operational Characteristics ◽  
Low Weight ◽  
New Feature ◽  
Processing Block ◽  
Conventional Ct

Optical Fiber Current transformers (OFCTs) are achieving increased acceptance and use in high voltage system due to their superior performance characteristics. It brings new feature to modern power system protection such as high accuracy, low weight, easy installation, and no-saturation. In this paper, a new OFCT is designed and implemented a long with a digital numeric system to protect electrical-feeder from over-current due to faults. Both the optical sensing head and electronic processing block are illustrated. A detailed experimental study to confirm the performances of the device is also reported. According to the measured values of ac rms current up to 2 kA, a calibration procedure was performed. The operational characteristics of the OFCT are investigated and three different scenarios based on Prototype were carried-out to evaluate the operation of the over-current protection using OFCT. The experiential results clearly illustrate the OFCT is capable to eliminate the distortion of the electrical signals caused by conventional (CT) and hence, greatly improving the reliability of the numerical protection system.

scholarly journals An Optical Fiber Sensor Based on La2O2S:Eu Scintillator for Detecting Ultraviolet Radiation in Real-Time

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3754 ◽  
Author(s):  
Yongji Yan ◽  
Xu Zhang ◽  
Haopeng Li ◽  
Yu Ma ◽  
Tianci Xie ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Response Time ◽  
Electromagnetic Interference ◽  
Uv Light ◽  
Optical Fiber Sensor ◽  
Temperature Response ◽  
Superior Performance ◽  
Fiber Sensor ◽  
Uv Detectors

A novel ultraviolet (UV) optical fiber sensor (UVOFS) based on the scintillating material La2O2S:Eu has been designed, tested, and its performance compared with other scintillating materials and other conventional UV detectors. The UVOFS is based on PMMA (polymethyl methacrylate) optical fiber which includes a scintillating material. Scintillating materials provide a unique opportunity to measure UV light intensity even in the presence of strong electromagnetic interference. Five scintillating materials were compared in order to select the most appropriate one for the UVOFS. The characteristics of the sensor are reported, including a highly linear response to radiation intensity, reproducibility, temperature response, and response time (to pulsed light) based on emission from a UV source (UV fluorescence tube) centered on a wavelength of 308 nm. A direct comparison with the commercially available semiconductor-based UV sensor proves the UVOFS of this investigation shows superior performance in terms of accuracy, long-term reliability, response time and linearity.

Feature Extraction and Representation for Distributed Multi-View Human Action Recognition

2013 ◽  
Vol 3 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Jiajia Luo ◽  
Wei Wang ◽  
Hairong Qi
Keyword(s):  
Action Recognition ◽  
Approximation Error ◽  
Human Action Recognition ◽  
Human Action ◽  
Base Station ◽  
Feature Representation ◽  
Superior Performance ◽  
Feature Descriptor ◽  
Testing Stage ◽  
New Feature

Multi-view human action recognition has gained a lot of attention in recent years for its superior performance as compared to single view recognition. In this paper, we propose a new framework for the real-time realization of human action recognition in distributed camera networks (DCNs). We first present a new feature descriptor (Mltp-hist) that is tolerant to illumination change, robust in homogeneous region and computationally efficient. Taking advantage of the proposed Mltp-hist, the noninformative 3-D patches generated from the background can be further removed automatically that effectively highlights the foreground patches. Next, a new feature representation method based on sparse coding is presented to generate the histogram representation of local videos to be transmitted to the base station for classification. Due to the sparse representation of extracted features, the approximation error is reduced. Finally, at the base station, a probability model is produced to fuse the information from various views and a class label is assigned accordingly. Compared to the existing algorithms, the proposed framework has three advantages while having less requirements on memory and bandwidth consumption: 1) no preprocessing is required; 2) communication among cameras is unnecessary; and 3) positions and orientations of cameras do not need to be fixed. We further evaluate the proposed framework on the most popular multi-view action dataset IXMAS. Experimental results indicate that our proposed framework repeatedly achieves state-of-the-art results when various numbers of views are tested. In addition, our approach is tolerant to the various combination of views and benefit from introducing more views at the testing stage. Especially, our results are still satisfactory even when large misalignment exists between the training and testing samples.

Current transformer based on optical fiber fluorescent thermometry

2008 ◽  
Author(s):  
Danping Jia ◽  
Ting Jia ◽  
Liang He ◽  
Yingwen Lin
Keyword(s):  
Optical Fiber ◽  
Current Transformer

Research of DC Current Transformer Based on Optical Fiber Thermometry

2012 ◽  
Vol 7 (2) ◽  
pp. 128-131 ◽  
Author(s):  
Danping Jia ◽  
Zhuo Yuan ◽  
Wei Lin ◽  
Hongli San
Keyword(s):  
Optical Fiber ◽  
Current Transformer ◽  
Dc Current

Error Calculating and Compensating Method of All-Optical Fiber Current Transformer in ± 10 kV DC Distribution Network

2019 ◽  
Vol 14 (11) ◽  
pp. 1606-1615
Author(s):  
Jicheng Yu ◽  
Changxi Yue ◽  
Jun Li ◽  
Dengyun Li ◽  
He Li
Keyword(s):  
Optical Fiber ◽  
Distribution Network ◽  
Current Transformer ◽  
Electromagnetic Current ◽  
Current Transformers ◽  
Wave Plate ◽  
Remote Transmission ◽  
Dc Distribution ◽  
All Optical ◽  
Database Technology

Current transformer is one of the main equipment in ±10 kV DC distribution network. Traditional electromagnetic current transformer has poor anti-jamming capacity and poor insulation, so it cannot realize transient protection. The emergence of all-optical fiber current transformer brings solutions to these problems, which has attracted more and more attention. In this study, aiming at the problem of error and compensation of λ/4 waveform of all-fiber current transformer, the fabrication method of λ/4 waveform is studied, the mathematical model of the waveform is established, the influence of the waveform error on the scale factor is analyzed, and a calculating device of angle difference and ratio difference to compare the error is designed. The device adopts the principle of traceability of quantities to collect the state data of the wave plate. At the same time, in order to collect data for errors, database technology and network technology are used to realize remote transmission of monitoring data. The error of the λ/4 wave plate is compensated, the bidirectional principle generated by the birefringence in the fiber ring is analyzed, and the data logic description of the transformer sensitive ring is performed. The phase delay and the angle of the shaft are selected as the main factors causing the error. Compensation is performed by means of peak segmentation and variable cancellation. In the experimental process, compared with the error sampling of the traditional transformer, the error calculated by the current amplitude and phase angle parameters obtained by the all-fiber current transformer is more accurate, and the compensation scheme can suppress the size of the birefringence and improve sensing accuracy of fiber optic current transformers. This study provides a powerful reference for the error analysis of all-fiber current transformer λ/4 wave plates, which is beneficial to promote the better application of such current transformers.

Application of Special Optical Fiber Sensing Technology in New Generation of Smart Substation

2014 ◽  
Vol 986-987 ◽  
pp. 1191-1195
Author(s):  
Rui Rui Yang ◽  
Hui Yuan Yang ◽  
Wei Chi Ou
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Current Transformer ◽  
Bragg Grating ◽  
Distributed Temperature Sensing ◽  
Fiber Sensing ◽  
Sensing Technology ◽  
Optical Fiber Sensing ◽  
New Generation ◽  
Smart Substation

The new generation of smart substation puts forward higher requirements to sensing technology. Based on the needs of these requirements, four kinds of special optical fiber sensing technology in power systems were researched: all-optical current transformer, distributed temperature sensing technology, fiber grating vibration sensing technology and fiber Bragg grating sensing technology. These kinds of optical fiber sensing technology for the new generation of smart substation to enhance its performance were analyzed. Finally, based on the fiber Bragg grating sensing technology, the online oil and winding temperature monitoring system was constructed for the new generation of smart substation.

Field trial of optical current transformer using optical fiber as Faraday sensor

2003 ◽  
Author(s):  
T. Kumai ◽  
H. Nakabayashi ◽  
Y. Hirata ◽  
M. Takahashi ◽  
K. Terai ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Field Trial ◽  
Current Transformer
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