Experimental results of electromechanical structure properties of noise and vibration on power transformers after lightning impulse test

2022 ◽  
Vol 134 ◽  
pp. 107458
Author(s):  
Chang-Hung Hsu
Keyword(s):  
Experimental Results ◽  
Power Transformers ◽  
Noise And Vibration ◽  
Lightning Impulse ◽  
Structure Properties

Overvoltage Produced by Lightning Impulse in High Power Transformers - Parameters that Influence their Transmission

2021 ◽  
Author(s):  
Maria-Cristina NITU ◽  
Marcel NICOLA ◽  
Claudiu-Ionel NICOLA ◽  
Ancuta-Mihaela ACIU ◽  
Daniel OCOLEANU ◽  
...  
Keyword(s):  
High Power ◽  
Power Transformers ◽  
Lightning Impulse

Identification of Critical Net Positive Suction Head From Noise and Vibration in a Radial Flow Pump for Different Leading Edge Profiles of the Vane

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
S. Christopher ◽  
S. Kumaraswamy
Keyword(s):  
Radial Flow ◽  
Leading Edge ◽  
Open Circuit ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Noise And Vibration ◽  
Operating Condition ◽  
Radial Flow Pump ◽  
Flow Pump

Experimental investigations concerning cavitation in radial flow pump for three different leading edge profiles of the vane were carried out in an open circuit system. The operating condition of the radial flow pump under cavitating case was understood by measurement of noise and vibration along with the pump parameters for various speeds and flow rates. The outcome of the experimental results revealed that the noise and vibration were better predictors of inception and development of cavitation. Further observation inferred from critical net positive suction head (NPSH) curve of 3% head drop and critical NPSH value of noise and vibration are presented.

The use of noise and vibration signals for detecting cavitation in kinetic pumps

2009 ◽  
Vol 223 (7) ◽  
pp. 1645-1655 ◽  
Author(s):  
J Černetič
Keyword(s):  
Mechanical Damage ◽  
Experimental Results ◽  
Vibration Signals ◽  
Noise And Vibration ◽  
Pumping System ◽  
Cavitation Phenomenon ◽  
Specific Frequency ◽  
Cavitation Detection

Cavitation in a kinetic pump reduces delivery head and efficiency of the pump. It also causes mechanical damage and an increase of vibrations and noise. Therefore, it is important to detect inception and development of a cavitation phenomenon in the pump. This article deals with signals of vibration and noise, which will be used for detection and monitoring of the cavitation in kinetic pumps, and also to prevent the effect of the cavitation in the pump and pumping system. When the cavitation is increasing, the flowing conditions are changing, which leads to an increase of vibrations of the pump and emitted noise in the surroundings. Because vibrations and noise are transferred from the pump through its casing, the signal is non-uniformly distorted due to transfer losses and structure of the casing surfaces. Noise and vibrations are increasing steadily, but in some specific frequency ranges the signal is more pronounced than in other parts of the spectrum. Experimental results have shown that vibration and noise in the audible spectrum can be successfully used for cavitation detection and its prevention.

Study on Detection Method of Transformer Winding Insulation Defects Based on Lightning Impulse Test

2013 ◽  
Vol 805-806 ◽  
pp. 847-850
Author(s):  
Yu Sheng Quan ◽  
Zi Sen Ning ◽  
Hua Gui Chen ◽  
Bo Yi
Keyword(s):  
Detection Method ◽  
Power Transformer ◽  
Power Transformers ◽  
Signal Source ◽  
Full Wave ◽  
Half Wave ◽  
Transformer Winding ◽  
Lightning Impulse ◽  
Recognition Criterion ◽  
Winding Insulation

Lightning impulse test for power transformer is a highly theoretical and empirical analysis tests for insulation assessment attaches great importance to the power transformer. Facing the problems of detection and diagnostic method based on lightning impulse test for power transformers, this paper proposes a new method of diagnosing the winding insulation defects using two groups of voltage and current with the half-wave and full-wave. This method treats parts of the lightning impulse voltage and current as the signal source, constructs recognition criterion which is closely related to the voltage and current, and diagnose transformer winding insulation defects. Whether the insulation damage exists in the transformer winding which has passed the lightning impulse test can also be diagnosed by the method.

On Site Oscillating Lightning Impulse Test and Insulation Diagnose for Power Transformers

2020 ◽  
Vol 35 (5) ◽  
pp. 2548-2550 ◽  
Author(s):  
Xuanrui Zhang ◽  
Minxia Shi ◽  
Cong He ◽  
Junhao Li
Keyword(s):  
Power Transformers ◽  
Lightning Impulse

scholarly journals Using the Analysis of the Gases Dissolved in Oil in Diagnosis of Transformer Bushings with Paper-Oil Insulation—A Case Study

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6713
Author(s):  
Tomasz Piotrowski ◽  
Pawel Rozga ◽  
Ryszard Kozak ◽  
Zbigniew Szymanski
Keyword(s):  
Positive Result ◽  
Gas Analysis ◽  
Power Transformers ◽  
Ratio Method ◽  
Dissolved Gas ◽  
Step Process ◽  
Lightning Impulse ◽  
Triangle Method ◽  
Inside Part

The article describes a case study when the voltage collapse during lightning impulse tests of new power transformers was noticed and when the repeated tests finished with a positive result. The step-by-step process of reaching the conclusion on the basis of dissolved gas analysis (DGA) as a key method of the investigations was presented. The considerations on the possible source of the analysis showed that the Duval triangle method, used in the analysis of the concentration of gases dissolved in oil samples taken from bushings, more reliably and unambiguously than the ratio method recommended in the IEC 60599 Standard, indicated a phenomenon which was identified in the insulation structure of bushings analyzed. Additionally, the results from DGA were found to be consistent with an internal inspection of bushings, which showed a visible trace of discharge on the inside part of the epoxy housing, as a result of the lightning induced breakdown.

Investigation of the Noise and Vibration of Planetary Gear Drives

2003 ◽  
Author(s):  
Yong Chen ◽  
Akira Ishibashi
Keyword(s):  
Phase Difference ◽  
Planetary Gear ◽  
Experimental Results ◽  
The Sun ◽  
Noise And Vibration ◽  
Helical Gears ◽  
Automatic Transmissions ◽  
Gear Drives

With the aim of reducing the operating noise and vibration of the planetary gearsets used in automotive automatic transmissions, a meshing phase difference was applied to the planet gears that mesh with the sun and ring gears. Shaved and hardened helical gears with and without grinding were used as the component gears that were tested under varying rotational speeds and tooth loads. The experimental results clearly showed that planetary gearset noise and vibration were reduced when a meshing phase difference was applied.

scholarly journals Systematic Design and Circuit Analysis of Lightning Impulse Voltage Generation on Low-Inductance Loads

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8010
Author(s):  
Peerawut Yutthagowith ◽  
Phattarin Kitcharoen ◽  
Anantawat Kunakorn
Keyword(s):  
Circuit Analysis ◽  
Experimental Results ◽  
Systematic Design ◽  
Load Range ◽  
Standard Requirement ◽  
Circuit Simulator ◽  
Component Selection ◽  
Impulse Voltage ◽  
Lightning Impulse ◽  
Series Resistor

The well-known circuit for the generation of lightning impulse voltage (LIV) on low-inductance loads was introduced by Glaninger in 1975, and the circuit component selection was proposed by Feser. However, the circuit and the approach for the component selection have some difficulties for which further adjustment is required for obtaining the waveform parameters according to the standard requirement. In this paper, an extended Glaninger’s circuit with an additional series resistor is proposed. Furthermore, a systematic design and circuit analysis of LIV generation for low-inductance loads are developed. With the help of a circuit simulator, the circuit analysis for the component selection is described. The validity of the proposed circuit was confirmed by some experimental results in comparison with the simulated ones. The proposed circuit and component selection provide not only the generation waveform according to the standard requirement but also other promising performances in terms of the wide inductance load range from 400 μH to 4 mH, a voltage efficiency of over 80%, an overshoot voltage of below 5%, an undershoot voltage of below 40%, and a maximum charging capacitance of 10 μF. From the simulated and experimental results, the proposed circuit and component selection approach is very useful for the LIV tests on low-inductance loads instead of using the conventional approach based on trial and error.

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