scholarly journals Comparative Study on Characteristics of Partial Discharge Optical Pulse and UHF Pulse in Switch Equipment

2021 ◽  
Vol 2136 (1) ◽  
pp. 012024
Author(s):  
Ping Chen ◽  
Jin Miao ◽  
Yin Gu ◽  
Fen Huang ◽  
Xinyang Zhou ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Optical Pulse ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Partial Discharge ◽  
Detection Methods ◽  
Statistical Characteristics ◽  
Photoelectric Sensor ◽  
Phase Interval ◽  
Physical Phenomena

Abstract The article explores the performance of the new silicon photoelectric sensor in partial discharge detection, and compares the measured optical pulse with the traditional UHF pulse. Through optical and electrical synchronous partial discharge experiments, the article analyzes and discusses the detection performance, working characteristics and statistical characteristics of various sensors, and explores the advantages and feasibility of silicon photoelectric partial discharge sensors in actual discharge monitoring; In addition, the statistical performance of the two physical phenomena of partial light radiation and electromagnetic radiation was obtained through the analysis of optical and electrical synchronous monitoring data. Compared with UHF sensor, silicon photoelectric sensor under the optimal working voltage has a higher signal-to-noise ratio (SNR); Under the electromagnetic interference of the high-frequency motor, silicon photoelectric sensor exhibits better anti-electromagnetic interference ability; Discharge phase interval and characteristics reflected by the PRPD obtained by two detection methods maintain good consistency; Pulse repetition rate has the same trend with applied voltage, but statistical frequency of optical pulses obtained is higher than that of electromagnetic pulses because silicon photoelectric sensor has a higher SNR and single-photon sensitivity.

scholarly journals Application of UHF Sensors in Power System Equipment for Partial Discharge Detection: A Review

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1029 ◽  
Author(s):  
Hua Chai ◽  
B.T. Phung ◽  
Steve Mitchell
Keyword(s):  
Power System ◽  
Electromagnetic Interference ◽  
Early Stage ◽  
Signal To Noise Ratio ◽  
Partial Discharge ◽  
Critical Role ◽  
Physical Structure ◽  
High Signal ◽  
Practical Applications ◽  
Electrical Stress

Condition monitoring of an operating apparatus is essential for lifespan assessment and maintenance planning in a power system. Electrical insulation is a critical aspect to be monitored, since it is susceptible to failure under high electrical stress. To avoid unexpected breakdowns, the level of partial discharge (PD) activity should be continuously monitored because PD occurrence can accelerate the aging process of insulation in high voltage equipment and result in catastrophic failure if the associated defects are not treated at an early stage. For on-site PD detection, the ultra-high frequency (UHF) method was employed in the field and showed its effectiveness as a detection technique. The main advantage of the UHF method is its immunity to external electromagnetic interference with a high signal-to-noise ratio, which is necessary for on-site monitoring. Considering the detection process, sensors play a critical role in capturing signals from PD sources and transmitting them onto the measurement system. In this paper, UHF sensors applied in PD detection were comprehensively reviewed. In particular, for power transformers, the effects of the physical structure on UHF signals and practical applications of UHF sensors including PD localization techniques were discussed. The aim of this review was to present state-of-the-art UHF sensors in PD detection and facilitate future improvements in the UHF method.

scholarly journals Measurement and Analysis of Partial Discharge using an Ultra-High Frequency Sensor for Gas Insulated Structures

2017 ◽  
Vol 24 (3) ◽  
pp. 515-524 ◽  
Author(s):  
Guoming Wang ◽  
Gyung-Suk Kil
Keyword(s):  
High Frequency ◽  
Partial Discharge ◽  
Detection Methods ◽  
Statistical Characteristics ◽  
Stable Operation ◽  
Ultra High Frequency ◽  
Real Time Measurement ◽  
On Line ◽  
Neural Network Algorithm ◽  
High Degree

AbstractAlthough the gas insulated structures have a high degree of reliability, the unavoidable defects are primary reason of their failures.Partial discharge(PD) has been regarded as an effective indication for condition monitoring and diagnosis ofgas insulated switchgears(GISs) to ensure their reliable and stable operation. Among various PD detection methods, theultra-high frequency(UHF) technique has the advantages of on-line motoring and defect classification. In this paper, there are presented 7 types of artificial electrode systems fabricated for simulation of real insulation defects in gas insulated structures. A real-time measurement system was developed to acquire defect patterns in a form ofphase-resolve partial discharge(PRPD) intensity graph, using a UHF sensor. Further, the discharge distribution and statistical characteristics were extracted for defect identification using a neural network algorithm. In addition, a conversion experiment was proposed by detecting the PD pulse simultaneously using a non-induction resistor and a UHF sensor. A relationship between the magnitude of UHF signal and the amplitude of apparent charge was established, which was used for evaluation of PD using the UHF sensor.

scholarly journals The Single-Photon Model of Search of Pulse Signals for Telecommunication Systems

2018 ◽  
Vol 7 (3.13) ◽  
pp. 17
Author(s):  
K Y. Rumyantsev ◽  
L A. Albogachieva ◽  
P D. Linenko
Keyword(s):  
Optical Pulse ◽  
Single Photon ◽  
Search Algorithm ◽  
Statistical Characteristics ◽  
Necessary Condition ◽  
Pass Band ◽  
Search System ◽  
Algorithm Efficiency ◽  
Radiation Sources ◽  
Spatial Element

Detection of the optical pulse reception moment is a necessary condition for communication between moving correspondents. The search algorithm of pulse signals in a photons registration mode (single-photon pulses) is known. It is considered that in a reception complex the optical signals period is known. The photoreception channel consists of an single-photon dissector, the electron amplifier, and the amplitude discriminator. In the time frame which is equal to the optic pulse-repetition period, the moment of amplitude discrimination level equality fixed. The analysis of the threshold reason excess is made in a following frame. At repeated excess of a threshold it is considered, that useful radiation is revealed. Otherwise the decision on absence of a source radiation is passed. The system passes to the review of a new spatial element of decomposing in supervised spaces. At the second excess of a threshold it is considered, that useful radiation is revealed. Otherwise the system passes to the review of a new spatial element of decomposing in controllable space. The model is developed for check of algorithm efficiency, measurement of statistical characteristics of search system of radiation sources with detection of the reception moment of optical pulse. In system the single-photon dissector with the limited pass-band is used. By means of the developed simulation model working capacity is proved and algorithm efficiency is checked up, statistical characteristics of search system of radiation sources with detection of the occurrence moment of a signal are measured at use of an single-photon dissector with the limited pass-band.  

Summary of Study on the GIS Partial Discharge Detection Technology and SF6 Alternative Gas

2013 ◽  
Vol 718-720 ◽  
pp. 611-616
Author(s):  
Yun Peng Liu ◽  
Zi Jian Wang ◽  
Yan Song Li
Keyword(s):  
Electromagnetic Waves ◽  
Partial Discharge ◽  
Detection Methods ◽  
Detection Technology ◽  
Foreign Countries ◽  
Insulation Defect ◽  
Long Time ◽  
Important Position ◽  
Physical Phenomena ◽  
Discharge Detection

Gas insulated switchgears occupy an important position in the power system. But the partial discharge would occur because of insulation defect, PD will lead to the GIS insulation damage after a long time, and will lead to serious consequences without treatment in time, therefore, the PD detection is particularly important. PD is detected by its secondary physical phenomena, including the phenomena of sound, light, electromagnetic waves and gas decomposition products and so on. At present, many scholars in China and foreign countries have done a comprehensive study on insulation detection technology of GIS and have achieved a large number of results. The author do a detailed overview on the detection technical of GIS insulation state, including GIS platform and the simulation of typical insulation defectspartial discharge detection methods, SF6 alternative gas and pattern recognition. These works provide a valuable reference for follow-up study of GIS.

scholarly journals Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ibtissame Khaoua ◽  
Guillaume Graciani ◽  
Andrey Kim ◽  
François Amblard
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Detection Methods ◽  
Strong Nonlinearity ◽  
Wide Range ◽  
Depth Analysis ◽  
Spatially Extended ◽  
Extended Sources ◽  
Photon Counting Mode

AbstractFor a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

scholarly journals On the Performance Analysis of Switched Diversity Combining Receivers over Fisher–Snedecor ℱ Composite Fading Channels

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3014
Author(s):  
Weijun Cheng ◽  
Xiaoting Wang ◽  
Tengfei Ma ◽  
Gang Wang
Keyword(s):  
Fading Channels ◽  
Error Probability ◽  
Signal To Noise Ratio ◽  
Multipath Fading ◽  
Performance Criteria ◽  
Statistical Characteristics ◽  
Diversity Combining ◽  
Systematic Analysis ◽  
Average Bit Error Probability ◽  
Switched Diversity Combining

In some emerging wireless applications, such as wearable communication and low-power sensor network applications, wireless devices or nodes not only require simple physical implementation approaches but also require certain reliable receiver techniques to overcome the effects of multipath or shadowed fading. Switched diversity combining (SDC) systems could be a simple and promising solution to the above requirements. Recently, a Fisher–Snedecor ℱ composited fading model has gained much interest because of its modeling accuracy and calculation tractability. However, the performance of SDC systems over ℱ fading channels has not yet been analyzed in the open literature. To this end, this paper presents a systematic analysis of SDC systems over ℱ fading channels, including dual-branch switch-and-stay combining (SSC), multibranch switch-and examine combining (SEC), and SEC with post-examining selection (SECps) systems. We first investigate the statistical characteristics of univariate and bivariate ℱ distributions. Then, these statistical expressions are introduced into the above SDC systems and the statistical metrics of the output signal-to-noise ratio (SNR) for these systems are deduced in different ℱ fading scenarios. Thirdly, certain exact and novel expressions of performance criteria, such as the outage probability, the average bit error probability and average symbol error probability, as well as the average channel capacity for SSC, SEC, and SECps are derived. To find the optimum performance, optimal analysis is performed for the independent and identically distributed cases. Finally, numerical evaluation and simulations are carried out to demonstrate the validity of the theoretical analysis under various ℱ fading scenarios. According to the obtained results, the multipath fading parameter has more influence on the performance of SDC systems than the shadowing parameter, the correlation coefficient, or the average SNR. Importantly, the SDC systems can provide switched diversity gains only when the switching threshold is not too large or too small compared to the average SNR.

Weak Transient Electromagnetic Radiation Signal Detection Method Considering the New Watershed Image Segmentation Algorithm

2019 ◽  
Vol 34 (03) ◽  
pp. 2054009
Author(s):  
Wenjun Huo ◽  
Peng Chu ◽  
Kai Wang ◽  
Liangting Fu ◽  
Zhigang Niu ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Cross Correlation ◽  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Estimation Method ◽  
Detection Methods ◽  
Signal To Noise ◽  
Long Distance ◽  
Transient Electromagnetic ◽  
Noise Ratio

In order to study the detection methods of weak transient electromagnetic radiation signals, a detection algorithm integrating generalized cross-correlation and chaotic sequence prediction is proposed in this paper. Based on the dual-antenna test and cross-correlation information estimation method, the detection of aperiodic weak discharge signals under low signal-to-noise ratio is transformed into the estimation of periodic delay parameters, and the noise is reduced at the same time. The feasibility of this method is verified by simulation and experimental analysis. The results show that under the condition of low signal-to-noise ratio, the integrated method can effectively suppress the influence of 10 noise disturbances. It has a high detection probability for weak transient electromagnetic radiation signals, and needs fewer pulse accumulation times, which improves the detection efficiency and is more suitable for long-distance detection of weak electromagnetic radiation sources.

An Automatic Paperless Velocity Measuring and Recording System

2014 ◽  
Vol 889-890 ◽  
pp. 745-748
Author(s):  
Jian Sheng Cao ◽  
Wan Jun Zhang ◽  
Xin Hua Zeng
Keyword(s):  
Flow Velocity ◽  
Optical Pulse ◽  
Electric Pulse ◽  
Automatic Monitoring ◽  
Time Intervals ◽  
Stream Flows ◽  
Fluid Flow Velocity ◽  
Photoelectric Sensor ◽  
Velocity Measuring ◽  
Short Time

Automatic monitoring of hydrologic properties such as water velocity at short-time intervals is critical for understanding watershed eco-hydrological processes. This can also be used to study the laws of stream flows and interactions ecological process. The advent of modern electronic technology (and the near-perfection of especially sensor and data collection technologies), has made it possible to use automatic monitoring systems to continuously measure hydrologic properties at short-time intervals. This paper introduces one such paperless flow velocity measuring/recoding system. The system uses a photoelectric sensor that is mainly comprised of photoelectric velocity sensor and pulse recorder. The system uses propellers (with reflective panels and photoemission cells) to transform flow velocities into optical pulse signals. It also uses photosensitive tubes to transform optical pulse signals into electric pulse signals. The electric pulse counts (generated in unit time) are recorded via pulse recorders. This therefore accomplishes automatic monitoring and continuous recording of fluid flow velocity.

Partial Discharge Detection Using Acoustic and Optical Methods in High Voltage Power Equipments: A Review

2013 ◽  
Vol 845 ◽  
pp. 283-286 ◽  
Author(s):  
Malik Abdul Razzaq Al Saedi ◽  
Mohd Muhridza Yaacob
Keyword(s):  
Acoustic Emission ◽  
High Voltage ◽  
Power Transformer ◽  
Partial Discharge ◽  
Optical Detection ◽  
Detection Threshold ◽  
Optical Methods ◽  
Detection Methods ◽  
Detection Techniques ◽  
Advantages And Disadvantages

There is a high risk of insulation system dielectric instability when partial discharge (PD) occurs. Therefore, measurement and monitoring of PD is an important preventive tool to safeguard high-voltage equipment from wanton damage. PD can be detected using optical method to increase the detection threshold and to improve the performance of on-line measurement of PD in noise environment. The PD emitted energy as acoustic emission. We can use this emitted energy to detect PD signal. The best method to detect PD in power transformer is by using acoustic emission. Optical sensor has some advantages such as; high sensitivity, more accuracy small size. Furthermore, in on-site measurements and laboratory experiments, it isoptical methodthat gives very moderate signal attenuations. This paper reviews the available PD detection methods (involving high voltage equipment) such as; acoustic detection and optical detection. The advantages and disadvantages of each method have been explored and compared. The review suggests that optical detection techniques provide many advantages from the consideration of accuracy and suitability for the applications when compared to other techniques.

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