scholarly journals Design of Partial Discharge Test Environment for Oil-Filled Submarine Cable Terminals and Ultrasonic Monitoring

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4774
Author(s):  
Yulong Wang ◽  
Xiaohong Zhang ◽  
Lili Li ◽  
Jinyang Du ◽  
Junguo Gao
Keyword(s):  
Partial Discharge ◽  
Maximum Amplitude ◽  
Signal Amplitude ◽  
Ultrasonic Signal ◽  
Signal Spectrum ◽  
Test Environment ◽  
Ultrasonic Signals ◽  
Amplitude Coefficient ◽  
Marine Cable ◽  
Submarine Cables

Based on the principle of operating an oil-filled-cable operation and the explanation of the oil-filling process provided in the cable operation and maintenance manual of submarine cables, this study investigated oil-pressure variation caused by gas generated as a result of cable faults. First, a set of oil-filled cables and their terminal oil-filled simulation system were designed in the laboratory, and a typical oil-filled-cable fault model was established according to the common faults of oil-filled cables observed in practice. Thereafter, ultrasonic signals of partial discharge (PD) under different fault models were obtained via validation experiments, which were performed by using oil-filled-cable simulation equipment. Subsequently, the ultrasonic signal mechanism was analyzed; these signals were generated via electric, thermal, and acoustic expansion and contraction, along with electric, mechanical, and acoustic electrostriction. Finally, upon processing the 400 experimental data groups, four practical parameters—maximum amplitude of the ultrasonic signal spectrum, Dmax, maximum frequency of the ultrasonic signals, fmax, average ultrasonic signal energy, Dav, and the ultrasonic signal amplitude coefficient, M—were designed to characterize the ultrasonic signals. These parameters can be used for subsequent pattern recognition. Thus, in this study, the terminal PD of an oil-filled marine cable was monitored.

Study on Ultrasonic Characteristics and Sensors in Partial Discharge

2011 ◽  
Vol 328-330 ◽  
pp. 1892-1895
Author(s):  
Guang Xing Zhao ◽  
Qing Yu
Keyword(s):  
Sound Pressure ◽  
Detection Method ◽  
Partial Discharge ◽  
Ultrasonic Signal ◽  
Signal Spectrum ◽  
Discharge Characteristics ◽  
Ultrasonic Signals ◽  
Piezoelectric Crystals ◽  
Performance Requirements ◽  
Selection Of

In partial discharge detection of transformer, supersonics detection method is applied widely. In the paper, a model of supersonics is established by MATLAB. Meanwhile, analyses about the relation between amplitude of sound pressure and discharge capacity and ultrasonic signal spectrum are implemented based on the model. By analyzing the partial discharge characteristics of ultrasonic signals, a suitable ultrasonic receiving sensor can be selected that meets the performance requirements. Therefore, detection band of sensor is determined. Meanwhile, the structure of the sensor and the selection of piezoelectric crystals are introduced in details.Finally,the design of ultrasonic receiving sensor is determined.

Study on Neural Networks Usage to Analyse Correlation between Spectrum of Vibration Acceleration Signal from Pin of Ball Mill and its Filling Level

2015 ◽  
Vol 770 ◽  
pp. 540-546 ◽  
Author(s):  
Yuri Eremenko ◽  
Dmitry Poleshchenko ◽  
Anton Glushchenko
Keyword(s):  
Neural Network ◽  
Ball Mill ◽  
Signal Amplitude ◽  
Signal Spectrum ◽  
Laboratory Model ◽  
Training Set ◽  
Vibration Acceleration ◽  
Acceleration Signal ◽  
The Neural Network ◽  
Trained Neural Network

The question about modern intelligent information processing methods usage for a ball mill filling level evaluation is considered. Vibration acceleration signal has been measured on a mill laboratory model for that purpose. It is made with accelerometer attached to a mill pin. The conclusion is made that mill filling level can not be measured with the help of such signal amplitude only. So this signal spectrum processed by a neural network is used. A training set for the neural network is formed with the help of spectral analysis methods. Trained neural network is able to find the correlation between mill pin vibration acceleration signal and mill filling level. Test set is formed from the data which is not included into the training set. This set is used in order to evaluate the network ability to evaluate the mill filling degree. The neural network guarantees no more than 7% error in the evaluation of mill filling level.

Are the initial frequency-modulated components of the mustached bat's biosonar pulses important for ranging?

1991 ◽  
Vol 66 (6) ◽  
pp. 1951-1964 ◽  
Author(s):  
D. C. Fitzpatrick ◽  
N. Suga ◽  
H. Misawa
Keyword(s):  
Maximum Amplitude ◽  
Signal Amplitude ◽  
Frequency Component ◽  
Target Range ◽  
Constant Frequency ◽  
Range Resolution ◽  
Mustached Bat ◽  
Pteronotus Parnellii ◽  
Target Ranging ◽  
The Mean

1. FM-FM neurons in the auditory cortex of the mustached bat, Pteronotus parnellii, are specialized to process target range. They respond when the terminal frequency-modulated component (TFM) of a biosonar pulse is paired with the TFM of the echo at a particular echo delay. Recently, it has been suggested that the initial FM components (IFMs) of biosonar signals may also be important for target ranging. To examine the possible role of IFMs in target ranging, we characterized the properties of IFMs and TFMs in biosonar pulses emitted by bats swung on a pendulum. We then studied responses of FM-FM neurons to synthesized biosonar signals containing IFMs and TFMs. 2. The mustached bat's biosonar signal consists of four harmonics, of which the second (H2) is the most intense. Each harmonic has an IFM in addition to a constant-frequency component (CF) and a TFM. Therefore each pulse potentially consists of 12 components, IFM1-4, CF1-4, and TFM1-4. The IFM sweeps up while the TFM sweeps down. 3. The IFM2 and TFM2 depths (i.e., bandwidths) were measured in 217 pulses from four animals. The mean IFM2 depth was much smaller than the mean TFM2 depth, 2.87 +/- 1.52 (SD) kHz compared with 16.27 +/- 1.08 kHz, respectively. The amplitude of the IFM2 continuously increased throughout its duration and was always less than the CF2 amplitude, whereas the TFM2 was relatively constant in amplitude over approximately three-quarters of its duration and was often the most intense part of the pulse. The maximum amplitude of the IFM2 was, on average, 11 dB smaller than that of the TFM2. Because range resolution increases with depth and the maximum detectable range increases with signal amplitude, the IFMs are poorly suited for ranging compared with the TFMs. 4. FM-FM neurons (n = 77) did not respond or responded very poorly to IFMs with depths and intensities similar to those emitted on the pendulum. The mean IFM2 depth at which a just-noticeable response appeared was 4.48 +/- 1.98 kHz. Only 14% of the pulses emitted on the pendulum had IFM2 depths that exceeded the mean IFM2 depth threshold of FM-FM neurons. 5. Most FM-FM neurons responded to IFMs that had depths comparable with those of TFMs. However, when all parameters were adjusted to optimize the response to TFMs and then readjusted to maximize the response to IFMs, 52% of 27 neurons tested responded significantly better to the optimal TFMs than to the optimal IFMs (P less than 0.05, t test).(ABSTRACT TRUNCATED AT 400 WORDS)

FEM Simulation of PD Acoustic Signal Propagation in Transformers

2013 ◽  
Vol 448-453 ◽  
pp. 2278-2285
Author(s):  
Yue Dong ◽  
Yong Qian ◽  
Hai Feng Ye ◽  
Xiu Chen Jiang
Keyword(s):  
Power Transformer ◽  
Ultrasonic Method ◽  
Partial Discharge ◽  
Fem Simulation ◽  
Signal Amplitude ◽  
Signal Propagation ◽  
Ultrasonic Waves ◽  
Diagnostic Methods ◽  
Power Transformers ◽  
The Finite Element Method

In order to study propagation process of partial discharge ultrasonic signal in power transformer, the finite element method is used for simulation modeling and calculation. Ultrasonic waves can be activated by partial discharges (PD) in power transformers. The ultrasonic method is used for evaluating the insulation condition of power transformers by analyzing the partial discharge signals information which is detected by AE sensors. Compared with other diagnostic methods the AE method causes relatively low disturbance, and measuring apparatus is simple and easy to use. This technique is noninvasive and immune to electromagnetic noise. Simulate partial discharge sources of different positions respectively. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the signal amplitude decays when it moves away from the PD source.

scholarly journals Ultrasonic Signal Reconstruction Using Compressed Sensing

2016 ◽  
Vol 855 ◽  
pp. 165-170
Author(s):  
Ren Jean Liou
Keyword(s):  
Compressed Sensing ◽  
Spline Interpolation ◽  
Signal To Noise Ratio ◽  
Signal Reconstruction ◽  
Sampling Theorem ◽  
Ultrasonic Signal ◽  
Ultrasonic Signals ◽  
Data Rates ◽  
Nyquist Rate ◽  
Simulation Results

Ultrasonic signal reconstruction for Structural Health Monitoring is a topic that has been discussed extensively. In this paper, we will apply the techniques of compressed sensing to reconstruct ultrasonic signals that are seriously damaged. To reconstruct the data, the application of conventional interpolation techniques is restricted under the criteria of Nyquist sampling theorem. The newly developed technique - compressed sensing breaks the limitations of Nyquist rate and provides effective results based upon sparse signal reconstruction. Sparse representation is constructed using Fourier transform basis. An l1-norm optimization is then applied for reconstruction. Signals with temperature characteristics were synthetically created. We seriously corrupted these signals and tested the efficacy of our approach under two different scenarios. Firstly, the signal is randomly sampled at very low rates. Secondly, selected intervals were completely blank out. Simulation results show that the signals are effectively reconstructed. It outperforms conventional Spline interpolation in signal-to-noise ratio (SNR) with low variation, especially under very low data rates. This research demonstrates very promising results of using compressed sensing for ultrasonic signal reconstruction.

scholarly journals High frequency photoacoustic characterization of single cells

2021 ◽  
Author(s):  
Eric Strohm
Keyword(s):  
Analytical Solution ◽  
Blood Cells ◽  
Single Cells ◽  
Signal Amplitude ◽  
Element Model ◽  
Photoacoustic Signal ◽  
Signal Spectrum ◽  
Spectral Features ◽  
Photoacoustic Spectrum ◽  
Horizontal Orientation

This dissertation presents the first photoacoustic study of single cells using ultra-high frequencies (UHF, over 100 MHz). At these frequencies, unique features occur in the photoacoustic signal spectrum which depend on the cell size, morphology and structure. A finite element model (FEM) was developed to simulate the photoacoustic signals from ideal spherical droplets containing a perfluorocarbon liquid and optically absorbing nanoparticles. The model was applied to droplets in suspension and on a boundary to examine how the photoacoustic spectrum varies with droplet size and configuration, and compared to measurements using a 375 MHz transducer. Good agreement in the spectral features between the measured values and the FEM and analytical solution were observed. For the droplet on a boundary, additional spectral features were observed there were correctly predicted by the FEM, but not the analytical solution. The FEM could be applied to situations where the analytical model cannot be used, such as the asymmetric shape of red blood cells (RBCs). Measurements of single RBCs were then compared to the FEM. The frequency location of the spectral minima shifted to higher frequencies as the RBC rotated from a vertical to horizontal orientation. The spectral minima shifted to lower frequencies as the RBC swelled from the normal biconcave shape to a spherical morphology. Healthy RBCs were differentiated from spherocytes, echinocytes and swollen RBCs using changes in the photoacoustic spectrum (p<0.001). These results suggest that the photoacoustic spectrum can be used to classify RBCs according to their shape and pathology. Classification of cells using the photoacoustic spectral features was applied to measurements of blood cells and circulating tumor cells (CTCs) such as melanoma and acute myeloid leukemia (AML) cells. Measurements of 89 cells showed that variations in the spectrum and signal amplitude could be used to identify and differentiate melanoma and AML cells from RBCs, thus identifying foreign cells in the bloodstream. This dissertation investigates how UHF photoacoustics can be used to identify and classify cells and particles in a sample using their photoacoustic spectra, with the end goal of using these methods to identify cell pathology and detect CTCs clinically.

scholarly journals Improving ultrasonic imaging of aluminum plates using phase modulation

2020 ◽  
Vol 15 (3) ◽  
pp. 1-5
Author(s):  
Rafael Mateus Tischer ◽  
Ricardo Tokio Higuti ◽  
Vander Teixeira Prado ◽  
Claudio Kitano
Keyword(s):  
Phase Modulation ◽  
Lamb Waves ◽  
Dead Zone ◽  
Ultrasonic Imaging ◽  
Experimental Tests ◽  
Ultrasonic Signal ◽  
Signal Phase ◽  
Ultrasonic Signals ◽  
Aluminum Plates ◽  
Image Simulations

Ultrasonic imaging using arrays is a widespread technique used in medical imaging, with increasing use in industry. Conventional techniques use amplitude information from the ultrasonic signals to produce the images. These amplitude images can be produced with high quality, but can also present limitations regarding dead zone, artifacts and detection of far reflectors. Coherence images based on the signal phase have been explored in some works, and produce an image that indicates the presence of a defect. In this work we explore he effect of phase modulation of the ultrasonic signal and its effect on the corresponding coherence image. Simulations and experimental tests in an aluminum plate using Lamb waves and a linear piezoelectric array show that the phase modulation hasadvantages over coherence images without phase modulation for defect indication.

Using Ultrasonic Signal Reflection to Characterize the Density and Viscosity of Fluids and Slurries

2002 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Margaret S. Greenwood
Keyword(s):  
Density Measurement ◽  
Ultrasonic Signal ◽  
Two Phase ◽  
Sensor Interface ◽  
Ultrasonic Signals ◽  
Fluid Sensor ◽  
Three Phase ◽  
Phase Systems ◽  
Entrained Air ◽  
Base Liquid

Ultrasonic signals can be used to interrogate many forms of two-phase systems, dense slurry-laden and three-phase suspensions. This paper describes using ultrasonic signal reflection at a fluid-sensor interface to characterize fluid and slurry density and viscosity. The sensor consists of a series of transducers mounted on a wedge with the base of the wedge in contact with the liquid. Ultrasonic beams, striking the wedge base at several angles, are reflected at the base-liquid interface to the receive transducers. The amount of reflection at this interface depends upon the density of the liquid, the speed of sound in the liquid, and the wedge parameters. The response of a shear wave transducer, in conjunction with a density measurement, is used to determine the viscosity. The sensor can be mounted in a pipeline configuration or submerged in a tank for process control of food products. Novel features include: the small size of the probe and the sensor robustness. Performance is not affected by fluid flow rate, entrained air, or vibration. Experimental measurements of the density and viscosity for fluids and slurries are presented.

scholarly journals Amplitude Distribution of Partial Discharge Signals on Tunnel-Installed High-Voltage Cables

2019 ◽  
Vol 9 (21) ◽  
pp. 4595 ◽  
Author(s):  
Yong Qian ◽  
Xiaoxin Chen ◽  
Yiming Zang ◽  
Hui Wang ◽  
Gehao Sheng ◽  
...  
Keyword(s):  
High Voltage ◽  
Partial Discharge ◽  
Current Method ◽  
Signal Amplitude ◽  
Amplitude Distribution ◽  
Xlpe Cable ◽  
Bonding Wires ◽  
Cable Laying ◽  
Cable Systems ◽  
The Cross

For 110 kV and above tunnel-installed high-voltage (HV) cross-linked poly-ethylene (XLPE) cable systems, it is a normal procedure to adopt a cross-bonding scheme. The high-frequency current method is frequently used in the cross-bonded cable systems for on-site or online partial discharge (PD) detection by monitoring the signals on the cross-bonding wires. To further study the amplitude distribution characteristics of the PD signals, a parametric characteristic admittance model of a three-phase cable system in a tunnel is established based on Tylavsky’s formulas. The model is used to calculate the amplitude distribution formula of the PD pulse current on the cross-bonding wires. In addition, the influence of cable laying and tunnel environment on the amplitude distribution is also studied. Finally, the correctness of the model and the conclusion are verified by simulation experiments and on-site tests. The results show that the signal amplitude distribution is determined by the ratio of the characteristic admittances. As the distance between the cables and the distance from the inner wall of the tunnel increase, the amplitude difference gradually decreases.

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