Separation Research of Ultrasonic Wave in Transformer Partial Discharge Based on Improved Waveform Matching

2013 ◽  
Vol 291-294 ◽  
pp. 2325-2330
Author(s):  
Hong Ling Xie ◽  
Fei Wang ◽  
Yan Qing Li ◽  
Fei Long Wang
Keyword(s):  
Ultrasonic Wave ◽  
Attenuation Coefficient ◽  
Partial Discharge ◽  
Ultrasonic Sensor ◽  
Separation Method ◽  
Signal Frequency ◽  
Direct Wave ◽  
Wave Signal ◽  
Position Accuracy ◽  
Wave Separation

The use of direct wave to locate the position of the PD source is of better accuracy in transformer partial discharge ultrasound array positioning. For the signal received by ultrasonic sensor is consisted by direct wave, non-direct wave and a variety of noise, a direct wave separation method based on improved waveform matching is proposed in this paper. It is considered that the direct wave first reaches the ultrasonic sensor. A benchmarks triangle is built and then the attenuation coefficient and the signal frequency are both calculated. In order to search the matching wave, the benchmarks triangle is to pan and zoom. Finally, the best matching waveform is selected from a large number of matching waveforms as a direct wave signal. The result of simulation shows that the method can isolate the ultrasonic direct wave signal from the received signal, which provides some theoretical guidance to improve the position accuracy of the PD source.

Research on Direct Wave Separation of PD Ultrasonic Signal Based on ICA

2013 ◽  
Vol 734-737 ◽  
pp. 2819-2823 ◽  
Author(s):  
Shan Shan Hou ◽  
Qing Xie ◽  
Le Xian Shi ◽  
Wei Tao Hu
Keyword(s):  
Time Delay ◽  
Principal Component ◽  
Signal Propagation ◽  
Ultrasonic Signal ◽  
Separate Analysis ◽  
Positioning Accuracy ◽  
Direct Wave ◽  
Wave Signal ◽  
Wave Separation ◽  
Noise Characteristics

For partial discharge of transformer ultrasonic detection method exists positioning accuracy problems, the main reason mostly due to the time delay selected error is analyzed, while the main reason for time delay selected error is due to the transformer PD ultrasonic signal propagation which is extremely complex, the signals received by the ultrasonic sensor are the direct wave, non-direct wave and a mixture of all kinds of noise superimposed, so in order to improve positioning accuracy the correct separation of the direct waves time delay is important, this paper proposes a method of transformer PD direct wave ultrasonic signal separation based on independent component analysis (ICA), by a separate analysis of the direct wave signal, non-direct wave signal and noise characteristics of each principal component, the use of ICA to separate from the mixed signal to extract the direct wave signal and select the time delay, simulation and experimental results demonstrate the feasibility of the method.

scholarly journals Study on measurement of sound attenuation coefficient in bubble wake by pool

2020 ◽  
Vol 206 ◽  
pp. 03013
Author(s):  
Jing Han ◽  
Shuai Lv ◽  
Zhongpeng Wu ◽  
Mingwei Zhang ◽  
Jin Bai
Keyword(s):  
Attenuation Coefficient ◽  
Bubble Size ◽  
Sound Attenuation ◽  
Signal Frequency ◽  
Sound Waves ◽  
Air Inlet ◽  
Stimulation Tests ◽  
Measurement Experiment ◽  
Small Bubbles ◽  
Attenuation Characteristics

In this paper, bubbles are generated by controlling the air inlet volume of the ceramic tube array with a gas divider valve. Stimulation tests of sound attenuation characteristics of the wake of bubbles in a laboratory pool are performed. A measurement experiment of sound attenuation coefficient was carried out in the case of still water and bubbles with different particle sizes. The signal frequency is 20-200kHz. Through experimental research, it is found that the existence of bubbles makes the sound attenuation coefficient significantly larger. And the attenuation coefficient is related to the frequency of the sound waves and the size of the bubbles. At the same frequency, the larger the bubble size , the larger the attenuation coefficient will be. When the bubble size is constant, the attenuation of the acoustic signal in small bubbles will change greatly below 50kHz. Above 50kHz, the attenuation coefficient changes relatively smoothly and the fluctuation is small. In the case of medium and large bubbles, the fluctuation of the attenuation coefficient becomes larger than that in the small bubbles. Finally, the theoretically calculated sound attenuation coefficient is compared with the experimentally measured results. And the change trends of the two results are basically the same.

Modelling of Acoustic Wave Propagation Due to Partial Discharge and Its Detection and Localization in an Oil-Filled Distribution Transformer

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 73-81 ◽  
Author(s):  
Sorokhaibam Nilakanta Meitei ◽  
Kunal Borah ◽  
Saibal Chatterjee
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Partial Discharge ◽  
Piezoelectric Sensor ◽  
Comsol Multiphysics ◽  
Distribution Transformer ◽  
Acoustic Wave Propagation ◽  
Wave Signal ◽  
Artificial Neural Network Ann ◽  
Detection And Localization

AbstractPartial discharge (PD) is the main cause of the insulation decay and hence periodical testing of the insulation condition of a distribution transformer is necessary. This paper presents a model of PD acoustic wave propagation, detection, and localization in an oil-filled distribution transformer using finite element method supported by COMSOL Multiphysics software. Using an acoustic module and AC/DC module of COMSOL Multiphysics software, oil filled distribution transformer, and the acoustic piezoelectric sensor are simulated to analyze and detect the PD inside the transformer. PD is numerically simulated in the transformer windings, core, and oil ducts that produce acoustic wave signal. The distribution of the acoustic pressure wave inside the model transformer is analyzed first. Next, the acoustic piezoelectric sensors are modelled at four different locations of the model transformer to detect the pressure acoustic wave signal induced due to PD in the transformer. Finally, using an artificial neural network (ANN), the localization, and identification of PD in various parts of the transformer have been analyzed. The results obtained for location and detection are quite encouraging.

Research on the Design of Intelligent Obstacle Avoidance Car Model Based on Ultrasonic Wave

2013 ◽  
Vol 461 ◽  
pp. 531-534
Author(s):  
Yu Zhu ◽  
Zhe Xin Han ◽  
Peng Kun Sun ◽  
Tian Hao Wang ◽  
Yin Han Gao
Keyword(s):  
Ambient Temperature ◽  
Ultrasonic Wave ◽  
Obstacle Avoidance ◽  
External Environment ◽  
Ultrasonic Sensor ◽  
Design System ◽  
Intelligent Vehicle ◽  
The Core ◽  
Car Model ◽  
Model Based

Based on the characteristic of an ultrasonic sensor that can sense the external environment, we design an intelligent vehicle with obstacle avoidance function. First, we use MSP430 as the core of the design system. Second, we distribute the ultrasonic sensor evenly on the round zone of the obstacles to process the data and ambient temperature, which is transmitted from the ultrasonic receiver through the SCM (what is SCM, explain). Finally, we make it to realize the functions of intelligent controlling and avoiding obstacles automatically.

CYCLIC THERMAL SHOCK PROPERTIES OF MOSI2 INTERMETALLIC MATERIALS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2922-2927 ◽  
Author(s):  
SANG PILL LEE ◽  
JIN KYUNG LEE ◽  
CHAE HO LEEM
Keyword(s):  
Flexural Strength ◽  
Thermal Shock ◽  
Ultrasonic Wave ◽  
Attenuation Coefficient ◽  
Thermal Shock Test ◽  
Drastic Reduction ◽  
Nondestructive Technique ◽  
Shock Test ◽  
Damage Degree ◽  
Intermetallic Materials

This paper dealt with the thermal shock damages of MoSi 2 intermetallics by a nondestructive technique. The flexural strength of MoSi 2 intermetallics depending on the thermal shock cycles has been also investigated. The thermal shock test was repeatedly performed up to 80 cycles at the temperature difference of 423 K. The flexural strength of MoSi 2 intermetallics decreased with the increase of thermal shock cycle, due to the creation of crack and its propagation. MoSi 2 intermetallics represented the drastic reduction of ultrasonic wave velocity at the thermal shock of 40 cycles. The attenuation coefficient of MoSi 2 intermetallics increased with increasing the thermal shock cycle due to the activation of damage degree

Study of PD Ultrasonic Wave's Properties in Solid Medium

2013 ◽  
Vol 860-863 ◽  
pp. 2161-2167
Author(s):  
Wei Qiang Qi ◽  
Yan Ran Li ◽  
Xiao Xin Chen ◽  
Da Peng Duan
Keyword(s):  
Ultrasonic Wave ◽  
Guided Waves ◽  
Body Wave ◽  
Partial Discharge ◽  
Metal Plate ◽  
Body Waves ◽  
Ultrasonic Guided Waves ◽  
Practical Applications ◽  
Longitudinal Ultrasonic Wave ◽  
Discharge Detection

Longitudinal ultrasonic wave signals, transverse ultrasonic wave signals and other ultrasonic body wave signals generated by partial discharge are analyzed emphatically in the acoustic emission method of partial discharge detection in high voltage equipment [1-. Velocity of longitudinal ultrasonic wave is often used to calculate partial discharge defects position in the location study of partial discharge. In practical applications errors are always large. And a recent study finds that a class of plate ultrasonic guided waves will be inspired when ultrasonic body waves are transmitted from the gaseous medium to the metal medium [9-1. As the attenuation coefficient is small and the transmission distance is large when the waves propagate along the metal plate, in the partial discharge detection, ultrasonic signals detected by the ultrasonic sensor attached to the equipment enclosure include ultrasonic guided waves besides the ultrasonic body waves.

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