Wide-area Synchronous Sampling Technique for Terminal Devices of Distribution IoT

2021 ◽  
Author(s):  
Sun Haoyang ◽  
Wang Peng ◽  
Guo Shen ◽  
Zhang Jichuan ◽  
Lin Jiaying
Keyword(s):  
Sampling Technique ◽  
Wide Area ◽  
Synchronous Sampling

Synchronous Analysis in Wind Turbine Gearbox Condition Monitoring

2012 ◽  
Author(s):  
Huageng Luo ◽  
Mingqi Luo ◽  
Shaobo Zhang
Keyword(s):  
Wind Turbine ◽  
Condition Monitoring ◽  
Signal To Noise Ratio ◽  
Sampling Technique ◽  
Signal To Noise ◽  
High Count ◽  
Wind Turbine Gearbox ◽  
Synchronous Sampling ◽  
Accuracy And Precision ◽  
Bearing Damage

This paper summarizes the application of “synchronous sampling” technique in the digital domain to enhance the signal-to-noise ratio in detection of wind turbine gear and bearing damage signatures. In this technique, only a once-per-revolution Key Phaser or a low-count Encoder signal is required. High-count synchronous sampling is achieved by resampling in the digital domain. Implementation and demonstration of the aforementioned techniques are illustrated in two current wind turbine field operation examples. The improvement in the accuracy and precision of damage feature extractions is demonstrated.

Synthesized Synchronous Sampling Technique for Differential Bearing Damage Detection

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Huageng Luo ◽  
Hai Qiu ◽  
George Ghanime ◽  
Melinda Hirz ◽  
Geo van der Merwe
Keyword(s):  
High Pressure ◽  
Signal To Noise Ratio ◽  
Sampling Technique ◽  
Health Conditions ◽  
Signal To Noise ◽  
High Pressure Turbine ◽  
Synchronous Sampling ◽  
Low Pressure Turbine ◽  
Conventional Analysis ◽  
Bearing Damage

The differential bearing between the low-pressure turbine (LPT) and high-pressure turbine (HPT) shafts is one of the most vulnerable parts in a turbomachinery engine. Unfortunately, it is also one of the most difficult parts to monitor for damage existence signatures, because the signal-to-noise ratio at the normal sensor locations is extremely low. In addition, the speed variations in both the LPT and HPT can further deteriorate the damage signature extracted by conventional analysis methods. In this paper, we developed a “synthesized synchronous sampling” technique to enhance the detection of differential bearing damage signature. Combining this technique together with the conventional acceleration enveloping technique, we are able to detect differential bearing damage at a much earlier stage, thus providing early warnings of the machinery health conditions.

scholarly journals Load angle estimation of synchronous generator

2020 ◽  
Vol 30 (30) ◽  
pp. 81-91
Author(s):  
Slavko Veinović ◽  
Žarko Janda ◽  
Đorđe Stojić ◽  
Jasna Dragosavac ◽  
Dušan Joksimović ◽  
...  
Keyword(s):  
Estimation Method ◽  
Systems Design ◽  
Sampling Technique ◽  
Synchronous Generator ◽  
Input Voltage ◽  
Discrete Fourier Transformation ◽  
Angle Estimation ◽  
Zero Crossing ◽  
Synchronous Sampling ◽  
Load Angle

In this paper a load angle estimation method of round rotor synchronous generator is presented, for load angle limiter in AVR systems design purpose. To get information of load angle, it is necessary to have values of the one terminal voltage, one phase current and q-axis reactance Xq. Mentioned values are acquired by synchronous sampling technique and processed by discrete Fourier transformation. The accuracy of presented method highly depends on quality of zero-crossing detection of the input voltage signal and on the calculation estimation of the fundamental frequency. This method is of reduced sensitivity to higher harmonics presence contence in voltages and current waveforms. Another advantage, when compared to other dq or ab based calculations estimations, is the necessity of use only two measurement channels. Drawback of described approach is lack of immunity to current asymmetry. However, a solution to overcome this problem is offered by introducing the additional measurements into the algorithm to extract the synchronous sampled direct components of all three phase currents.

Algorithms for automated montage synthesis of images from laser-scanning confocal microscopes

1995 ◽  
Vol 53 ◽  
pp. 650-651
Author(s):  
D. E. Becker
Keyword(s):  
Image Analysis ◽  
High Resolution ◽  
Laser Scanning ◽  
Cell Counting ◽  
Wide Area ◽  
Data Set ◽  
Computational Synthesis ◽  
Automated Cell Counting ◽  
Partial View ◽  
The Individual

An efficient, robust, and widely-applicable technique is presented for computational synthesis of high-resolution, wide-area images of a specimen from a series of overlapping partial views. This technique can also be used to combine the results of various forms of image analysis, such as segmentation, automated cell counting, deblurring, and neuron tracing, to generate representations that are equivalent to processing the large wide-area image, rather than the individual partial views. This can be a first step towards quantitation of the higher-level tissue architecture. The computational approach overcomes mechanical limitations, such as hysterisis and backlash, of microscope stages. It also automates a procedure that is currently done manually. One application is the high-resolution visualization and/or quantitation of large batches of specimens that are much wider than the field of view of the microscope.The automated montage synthesis begins by computing a concise set of landmark points for each partial view. The type of landmarks used can vary greatly depending on the images of interest. In many cases, image analysis performed on each data set can provide useful landmarks. Even when no such “natural” landmarks are available, image processing can often provide useful landmarks.

On convenient use of nanoprobe and scanning without a stem unit in an EM-420

1987 ◽  
Vol 45 ◽  
pp. 138-139
Author(s):  
K. K. Christenson ◽  
J. A. Eades
Keyword(s):  
Wide Area ◽  
Pole Piece ◽  
Operating Condition ◽  
Objective System

One of the strengths of the Philips EM-400 series of TEMs is their ability to operate under two distinct optical configurations: “microprobe”, the normal TEM operating condition which allows wide area illumination, and “nanoprobe”, which gives very small probes with high angular convergence for STEM imaging, microchemical and microstructural analyses. This change is accomplished by effectively turning off the twin lens located in the upper pole piece which changes the illumination from a telefocus system to a condenser-objective system. The deflection and tilt controls and alignments are designed for microprobe use and do not function properly when in nanoprobe. For instance, in nanoprobe the deflection control gives a mix of deflection and tilt; as does the tilt control.

Evaluation of bag sequential sampling technique for ambient air analysis. Comments

1979 ◽  
Vol 13 (5) ◽  
pp. 609-610
Author(s):  
Allen Hoffman ◽  
Roger Sperling ◽  
John Polasek ◽  
Jerry Bullin
Keyword(s):  
Sequential Sampling ◽  
Sampling Technique ◽  
Ambient Air ◽  
Air Analysis
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