Durable and Selective Electrochemical H2O2 Synthesis under a Large Current Enabled by the Cathode with Highly Hydrophobic Three-Phase Architecture

Research on Mechanical Defect Detection and Diagnosis Method for GIS Equipment Based on Vibration Signal

Energies ◽

10.3390/en14175507 ◽

2021 ◽

Vol 14 (17) ◽

pp. 5507

Author(s):

Liang He ◽

Jie Yang ◽

Ziwei Zhang ◽

Zongwu Li ◽

Dengwei Ding ◽

...

Keyword(s):

Experimental Research ◽

Detection System ◽

Engineering Application ◽

Vibration Signal ◽

Signal Amplitude ◽

Field Application ◽

Large Current ◽

Three Phase ◽

Diagnosis Method ◽

Detection And Diagnosis

Gas insulated switchgear equipment (GIS) is widely used in power system, and more attention has been paid to discharge defects than mechanical defects. However, since mechanical defects are a major cause of the failure in GIS, it is of great significance to carry out relevant research on mechanical defects. Detection and diagnosis methods of mechanical defects based on vibration signal are studied in this paper. Firstly, vibration mechanisms of GIS are analyzed. Due to structural differences between single phase insulated type GIS and three phase insulated type GIS, there are big differences in vibration mechanisms between the two types of GISs. Secondly, experimental research on mechanical defects is carried out based on a 110 kV GIS equipment and a self-developed vibration detection system; results show that mechanical defects can be diagnosed by analyzing signal amplitude, frequency spectrum and waveform distortion rate, and a large current is more beneficial for diagnosing mechanical defects. Lastly, field application has been carried out on 220 kV GIS equipment, and a poor contact defect is found, demonstrating that abnormal diagnosis can be realized by method proposed in this paper. Experimental research and field application demonstrate the feasibility and effectiveness of detection and diagnosis method for mechanical defects based on vibration signal and provide experience for subsequent engineering application.

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Transient Phenomena during the Three-Phase 300MVA Transformer Energization on the Transmission Network

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v6i6.11406 ◽

2016 ◽

Vol 6 (6) ◽

pp. 2499

Author(s):

Emir Alibašić ◽

Predrag Marić ◽

Srete N Nikolovski

Keyword(s):

Negative Impact ◽

Time Moment ◽

Inrush Current ◽

Transient Phenomena ◽

Transformer Protection ◽

Voltage Drops ◽

Large Current ◽

Saturation Region ◽

Three Phase ◽

Transformer Core

Connecting the transformer to the network may incur inrush current, which is significantly higher than the rated current of the transformer. The main cause of this phenomenon lies in the nonlinearity of the magnetic circuit. The value of the inrush current depends of the time moment of the energization and the residual magnetism in the transformer core. While connecting, the operating point of the magnetization characteristic can be found deep in the saturation region resulting in occurrence of large transformer currents that can trigger the transformer protection. Tripping of protection immediately after the transformer energization raises doubts about the transformer health. Inrush current can cause a number of other disadvantages such as the negative impact on other transformers connected on the same busbar; the increase of the transformer noise due to the large current value, the increase of the voltage drops in the network. The paper presents a simulation of the 300 MVA transformer energization using the MATLAB/Simulink software.

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Three-Phase Contact Formation and Flotation of Highly Hydrophobic Polytetrafluoroethylene in the Presence of Increased Dose of Frothers

Industrial & Engineering Chemistry Research ◽

10.1021/acs.iecr.5b04293 ◽

2016 ◽

Vol 55 (3) ◽

pp. 839-843 ◽

Cited By ~ 13

Author(s):

Przemyslaw B. Kowalczuk ◽

Jan Zawala ◽

Dominik Kosior ◽

Jan Drzymala ◽

Kazimierz Malysa

Keyword(s):

Phase Contact ◽

Contact Formation ◽

Three Phase ◽

Highly Hydrophobic

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Transient Phenomena during the Three-Phase 300MVA Transformer Energization on the Transmission Network

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v6i6.pp2499-2505 ◽

2016 ◽

Vol 6 (6) ◽

pp. 2499

Author(s):

Emir Alibašić ◽

Predrag Marić ◽

Srete N Nikolovski

Keyword(s):

Negative Impact ◽

Time Moment ◽

Inrush Current ◽

Transient Phenomena ◽

Transformer Protection ◽

Voltage Drops ◽

Large Current ◽

Saturation Region ◽

Three Phase ◽

Transformer Core

Connecting the transformer to the network may incur inrush current, which is significantly higher than the rated current of the transformer. The main cause of this phenomenon lies in the nonlinearity of the magnetic circuit. The value of the inrush current depends of the time moment of the energization and the residual magnetism in the transformer core. While connecting, the operating point of the magnetization characteristic can be found deep in the saturation region resulting in occurrence of large transformer currents that can trigger the transformer protection. Tripping of protection immediately after the transformer energization raises doubts about the transformer health. Inrush current can cause a number of other disadvantages such as the negative impact on other transformers connected on the same busbar; the increase of the transformer noise due to the large current value, the increase of the voltage drops in the network. The paper presents a simulation of the 300 MVA transformer energization using the MATLAB/Simulink software.

Download Full-text