scholarly journals Surface Discharge Mechanism on Epoxy Resin in Electronegative Gases and Its Application

2020 ◽  
Vol 10 (19) ◽  
pp. 6673
Author(s):  
Herie Park ◽  
Dong-Young Lim ◽  
Sungwoo Bae
Keyword(s):  
Sulfur Hexafluoride ◽  
Design Method ◽  
Surface Discharge ◽  
Uniform Field ◽  
Dielectric Characteristics ◽  
Discharge Mechanism ◽  
Dry Air ◽  
Surface Flashover ◽  
Flashover Voltage ◽  
Insulation Performance

This study presents the surface discharge characteristics of insulating gases, including sulfur hexafluoride (SF6), dry air, and N2, under a non-uniform field. Surface discharge experiments were conducted, with the gas pressure ranging from 0.1 to 0.6 MPa, on samples of epoxy dielectrics under an AC voltage. The experimental results showed that the surface insulation performance significantly improved in insulating gases possessing electronegative gases, such as SF6 and dry air. Surface flashover voltages of SF6 were saturated with an increasing pressure, compared to dry air and N2. The surface discharge mechanism is proposed to explain the improvement and saturation of dielectric characteristics of the electronegative gas in complex dielectric insulations, as well as its influence on the surface flashover voltage. As an application, an insulation design method is discussed with regards to replacing SF6 gas in high-voltage power equipment based on the knowledge of the physics behind gas discharge.

A Design Method of Rain Test Device Based on Water Drop Motion Simulation

2013 ◽  
Vol 871 ◽  
pp. 363-368
Author(s):  
Hong Tao Zeng ◽  
Lin Lin Lin ◽  
Cong Feng ◽  
Zhi Huai Xiao
Keyword(s):  
Design Method ◽  
Water Drop ◽  
Electrical Equipment ◽  
Simulation Software ◽  
Test Device ◽  
Rainy Weather ◽  
Drop Motion ◽  
Water Drops ◽  
Motion Characteristics ◽  
Insulation Performance

In order to measure the electric insulation performance of the electrical equipment in rainy weather, its essential to design a rain device to simulate different conditions of rainfall. In this paper, a motion model of raindrop sprayed by the rain device and differential equations describing its motion characteristics are built. Basing on the analysis of water drop motion, a set of simulation software is developed for the selection of rain test device and the analysis of test results. The software can simulate the water drops motion process from nozzle to test equipment, and the simulation results is almost the same with field test, so the simulation software provides the basis for the design of rain test device.

scholarly journals AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1710 ◽  
Author(s):  
Houssem Eddine Nechmi ◽  
Mohammed El Amine Slama ◽  
Abderrahmane (Manu) Haddad ◽  
Gordon Wilson
Keyword(s):  
Electrical Strength ◽  
Gas Mixture ◽  
Nonlinear Behaviour ◽  
Co2 Gas ◽  
Surface Flashover ◽  
Surface Finishes ◽  
Needle Position ◽  
Flashover Voltage ◽  
Solid Insulator ◽  
Solid Dielectrics

AC pre-discharge currents, breakdown, and flashover voltage measurements are reported in a 10 mm needle-plane arrangement in a 4% NovecTM 4710/96% CO2 gas mixture and compared with CO2 for pressures up to 8.8 bar abs. Flashover measurements were performed on different solid dielectrics (Al2O3_filled epoxy resins, PTFE (Polytetrafluoroethylene) and PE (polyethylene)) for different roughness surface finishes. The effect of fixed conducting needles at various positions on electrical strength is reported. A strong nonlinear behaviour as function of gas pressure was observed for all the studied parameters (gas, needle position, solid insulator, insulator roughness). The non-linear behaviour is attributed to the inception and quenching of glow corona, in the interval between inception and breakdown or flashover voltages. It is found that a 4% concentration of NovecTM 4710 in CO2 has a breakdown/flashover voltage ≈ 1.14 higher than CO2. The glow corona-induced stabilization effect is seen for pressures between 2 and 5 bar abs for all the studied parameters. The peak flashover voltage and its associated pressure of the different insulators are strongly dependent on surface roughness. At 8.8 bar abs, the flashover voltage level obtained with various materials was ordered as follows: PTFE > PE-UHMW > Epoxy > HDPE(High-density polyethylene).

Study on Discharge of Separated Water Droplets in DC Field

2011 ◽  
Vol 130-134 ◽  
pp. 3276-3279
Author(s):  
Zong Xi Zhang ◽  
Shan Feng Yin
Keyword(s):  
Electric Field ◽  
Hydrophobic Surface ◽  
Electrical Equipment ◽  
Water Droplets ◽  
Surface Flashover ◽  
Voltage Drops ◽  
Flashover Voltage ◽  
Dc Electric Field ◽  
Water Drops ◽  
And Migration

With the accelerating construction of strong smart grid, and the grid voltage level rising, performance requirements for the electrical insulation of electrical equipment also continue to increase. In terms of the advantages of RTV on antifouling, RTV-based paints coated insulator coating capacity of its flash tolerance can significantly increase, mainly due to RTV coating hydrophobic hydrophobicity and migration. But when the hydrophobic surface is in the fully wet, many small drops of water in the surface will be gathered into big drops of water, and these large droplets will distort the surface electric field of the medium. So the flashover voltage of the hydrophobic surface’s separated water droplets under DC electric field are analyzed comparatively in this paper, while some influencing factors such as different medias and volume of water drops, are introduced in specific experiments, and their effects on the flashover voltage are analyzed; under DC electric field experiment on the surface of hydrophobic and hydrophilic surface flashover voltage drops separation characteristics were studied.

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