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Zhu M, Wang X, Chang J, Zhou H. Improved PGC demodulation algorithm for fiber optic interferometric sensors. OPTICS EXPRESS 2024; 32:2162-2178. [PMID: 38297752 DOI: 10.1364/oe.506910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/26/2023] [Indexed: 02/02/2024]
Abstract
An improved phase generated carrier arctangent demodulation algorithm based on harmonic mixing and phase quadrature technology (PGC-Arctan-HP) is proposed in this paper, which can eliminate the effects of modulation depth shift, carrier phase delay, and light intensity disturbance (LID) on the demodulation results. The simulation results are consistent with theoretical analysis, and indicate that the PGC-Arctan-HP algorithm can achieve optimal demodulation compared with other demodulation algorithms. The results of interferometric experiments show that the demodulated waveforms of the improved algorithm are relatively stable with an amplitude error of 0.0294%. The total-harmonic-distortion (THD) and the signal-to-noise-and-distortion (SINAD) can reach -60.0286 dB and 59.5388 dB.
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Liu Q, Yu Y, Han BS, Zhou W. An Improved Spectral Subtraction Method for Eliminating Additive Noise in Condition Monitoring System Using Fiber Bragg Grating Sensors. SENSORS (BASEL, SWITZERLAND) 2024; 24:443. [PMID: 38257536 PMCID: PMC10821454 DOI: 10.3390/s24020443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024]
Abstract
The additive noise in the condition monitoring system using fiber Bragg grating (FBG) sensors, including white Gaussian noise and multifrequency interference, has a significantly negative influence on the fault diagnosis of rotating machinery. Spectral subtraction (SS) is an effective method for handling white Gaussian noise. However, the SS method exhibits poor performance in eliminating multifrequency interference because estimating the noise spectrum accurately is difficult, and it significantly weakens the useful information components in measured signals. In this study, an improved spectral subtraction (ISS) method is proposed to enhance its denoising performance. In the ISS method, a reference noise signal measured by the same sensing system without working loads is considered the estimated noise, the same sliding window is used to divide the power spectrums of the measured and reference noise signals into multiple frequency bands, and the formula of spectral subtraction in the standard SS method is modified. A simulation analysis and an experiment are executed by using simulated signals and establishing a vibration test rig based on the FBG sensor, respectively. The statistical results demonstrate the effectiveness and feasibility of the ISS method in simultaneously eliminating white Gaussian noise and multifrequency interference while well maintaining the useful information components.
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Affiliation(s)
- Qi Liu
- Schaeffler Hub for Advanced Research at NTU, 61 Nanyang Dr, ABN-B1b-11, Singapore 637460, Singapore; (Q.L.); (Y.Y.); (B.S.H.)
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Yongchao Yu
- Schaeffler Hub for Advanced Research at NTU, 61 Nanyang Dr, ABN-B1b-11, Singapore 637460, Singapore; (Q.L.); (Y.Y.); (B.S.H.)
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Boon Siew Han
- Schaeffler Hub for Advanced Research at NTU, 61 Nanyang Dr, ABN-B1b-11, Singapore 637460, Singapore; (Q.L.); (Y.Y.); (B.S.H.)
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Wei Zhou
- Schaeffler Hub for Advanced Research at NTU, 61 Nanyang Dr, ABN-B1b-11, Singapore 637460, Singapore; (Q.L.); (Y.Y.); (B.S.H.)
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Fakiris E, Papatheodorou G, Christodoulou D, Roumelioti Z, Sokos E, Geraga M, Giannakopoulos V, Dimas X, Ferentinos G. Using Distributed Temperature Sensing for Long-Term Monitoring of Pockmark Activity in the Gulf of Patras (Greece): Data Processing Hints and Preliminary Findings. SENSORS (BASEL, SWITZERLAND) 2023; 23:8520. [PMID: 37896613 PMCID: PMC10610646 DOI: 10.3390/s23208520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023]
Abstract
Patras Gulf pockmark field (Western Greece) is a tectonically controlled field that has been activated at least twice by strong earthquakes (M5.4, 14 July 1993 and M6.4, 8 June 2008), and episodic gas seepages have been recorded in the past using geophysical means. A distributed temperature sensor (DTS) system was deployed inside a shallow pockmark and along an active fault at the northern end of the field. This ongoing experiment represents the first long-term monitoring ever conducted on gas-bearing pockmarks and active faults by the DTS system. For now, we have acquired and analyzed data regarding about 1.56 years. One of the primary objectives of this study is to establish methodological queues for data processing and analysis, including spectral analysis and incomplete data treatment techniques, to be standardized for use in further stages of the experiment. Spectral analysis was proven capable of separating the temperature footprint of background environmental components, such as sea-atmosphere heat flux, tides, and winds/waves, from high-frequency temperature residuals. Those residuals represent unusual events that might be correlated to seismicity. Monitoring the causal relationship between seismic activity and seabed water temperature changes in the field was thus attempted. No significant local earthquakes occurred during the monitoring period. Although the relation between seismicity and irregular seabed water temperature events was not systematic, we postulate that four thermal events have a causative link with the local seismicity. The DTS system constitutes a low-cost monitoring system, and the promising preliminary results of this experiment suggest that it is worth testing for a longer period.
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Affiliation(s)
- Elias Fakiris
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - George Papatheodorou
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - Dimitris Christodoulou
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - Zafeiria Roumelioti
- Seismological Laboratory, Department of Geology, University of Patras, 26504 Patras, Greece; (Z.R.); (E.S.)
| | - Efthimios Sokos
- Seismological Laboratory, Department of Geology, University of Patras, 26504 Patras, Greece; (Z.R.); (E.S.)
| | - Maria Geraga
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - Vasileios Giannakopoulos
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - Xenophon Dimas
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
| | - George Ferentinos
- Laboratory of Marine Geology and Physical Oceanography (Oceanus-Lab), Department of Geology, University of Patras, 26504 Patras, Greece; (E.F.); (D.C.); (M.G.); (V.G.); (X.D.); (G.F.)
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Bassan FR, Rosolem JB, Floridia C, Penze RS, Aires BN, Roncolatto RA, Peres R, Júnior JRN, Fracarolli JPV, da Costa EF, Cardoso FH, Pereira FR, Furoni CC, Coimbra CM, Riboldi VB, Omae C, de Moraes M. Multi-Parameter Optical Monitoring Solution Applied to Underground Medium-Voltage Electric Power Distribution Networks. SENSORS (BASEL, SWITZERLAND) 2023; 23:5066. [PMID: 37299795 PMCID: PMC10255439 DOI: 10.3390/s23115066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/09/2023] [Accepted: 05/18/2023] [Indexed: 06/12/2023]
Abstract
This work presents a multi-parameter optical fiber monitoring solution applied to an underground power distribution network. The monitoring system demonstrated herein uses Fiber Bragg Grating (FBG) sensors to measure multiple parameters, such as the distributed temperature of the power cable, external temperature and current of the transformers, liquid level, and intrusion in the underground manholes. To monitor partial discharges of cable connections, we used sensors that detect radio frequency signals. The system was characterized in the laboratory and tested in underground distribution networks. We present here the technical details of the laboratory characterization, system installation, and the results of 6 months of network monitoring. The data obtained for temperature sensors in the field tests show a thermal behavior depending on the day/night cycle and the season. The temperature levels measured on the conductors indicated that in high-temperature periods, the maximum current specified for the conductor must be reduced, according to the applied Brazilian standards. The other sensors detected other important events in the distribution network. All the sensors demonstrated their functionality and robustness in the distribution network, and the monitored data will allow the electric power system to have a safe operation, with optimized capacity and operating within tolerated electrical and thermal limits.
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Affiliation(s)
- Fabio R Bassan
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Joao B Rosolem
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Claudio Floridia
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Rivael S Penze
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Bruno N Aires
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Ronaldo A Roncolatto
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Rodrigo Peres
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - João R Nogueira Júnior
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | | | - Eduardo F da Costa
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Filipe H Cardoso
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Fernando R Pereira
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | - Carla C Furoni
- CPQD-Research and Development Center in Telecommunications, Campinas 13086-902, SP, Brazil
| | | | | | - Camila Omae
- CPFL Energia, Campinas 13088-900, SP, Brazil
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