A5020243749- High voltage insulation and dielectric phenomena
- Aerosol Filtration and Electrostatic Precipitation
- Thermal Analysis in Power Transmission
- Dielectric materials and actuators
- Lightning and Electromagnetic Phenomena
- Advanced Sensor and Energy Harvesting Materials
- Power Transformer Diagnostics and Insulation
- Electrostatic Discharge in Electronics
- Advanced Image and Video Retrieval Techniques
- Plasma Diagnostics and Applications
- Electromagnetic wave absorption materials
- Visual Attention and Saliency Detection
- High-Voltage Power Transmission Systems
- Magnetic and transport properties of perovskites and related materials
- 2D Materials and Applications
- Face Recognition and Perception
- Geophysical Methods and Applications
- Elevator Systems and Control
- Quantum Dots Synthesis And Properties
- Vibration and Dynamic Analysis
Tianjin University
2022-2025
Surface charge and electric field distributions of a tri-post insulator in ±800-kV gas-insulated transmission line (GIL) are calculated under the superimposed dc-impulse voltage polarity reversal voltage. The theoretical discharge inception abovementioned conditions is estimated by volume-time theory. accumulated homocharges on surface significantly relax at dc steady state, thus improving homopolar impulse but reducing that heteropolar When reversed two minutes, intensified shifts from...
This study discusses the application of surface conductivity gradient materials ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> -SFGMs) for relaxing electric field concentration around epoxy-based spacer in high-voltage direct current gas-insulated transmission lines (HVDC GIL). Based on ±500-kV HVDC GIL model, iterative method is applied to optimize thickness...
This study discusses the application of multidimensional functionally graded materials ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -/ notation="LaTeX">$\sigma -MFGM) for epoxy spacers in offshore bipolar high-voltage direct current (HVDC) gas-insulated switchgears (GIS), which may be exposed to dc–ac mixed voltage. Based on a cone-type spacer model,...
Gas insulated switchgear (GIS) can encounter the voltage that combines both AC and DC components in a bipolar HVDC. systems. To enhance insulation performance of epoxy insulator, researchers developed new type material called multi-dimensional functionally graded materials (MFGM). This integrates two types materials, namely surface nonlinear conductivity (SNCM) bulk permittivity ($\varepsilon-\mathbf{F G M}$). The MFGM insulator consists SNCM layer $\varepsilon-\mathbf{F M}$ bulk, which were...
To optimize the electric field distribution of HVDC GIL spacer under working conditions, variable temperature surface functionally graded materials (VT-SFGM) with consideration room and gradient are designed. After iterative optimization, convex coating thickness VT-SFGM presents a U-shaped distribution. Under constant condition, strength at same position is reduced by 49.5%. As rises, high area uniform gradually transfers form HV conductor to GND shell. 60°C, maximum VTSFGM decreases 64%....
Surface charge and electric field distributions of a tri-post insulator in ±800 kV gas-insulated transmission line (GIL) are calculated under the transient voltages (superimposed DC-impulse voltage polarity reversal voltage). The theoretical discharge inception above conditions is estimated by volume-time theory. accumulated homo-charges on surface significantly relax at DC steady state, thus improving superimposed homopolar impulse but reducing that heteropolar voltage. When reversed 120 s,...
Metal particles seriously threaten the safe and stable operation of GIS/GIL, resulting in insulation failures frequently. This paper proposes a novel method to actively suppress metal particle contamination by using functionally graded materials ($\varepsilon$-FGM). Based on 220 kVGIS/GIL model, electric field distributions as well trajectories around spacer are studied simulation. Results show that $\varepsilon$-FGM can not only uniform distribution but also drive away surrounding...
The study discusses the application of multi-dimensional functionally graded materials ($\varepsilon$/$\sigma$-MFGM) for spacers in offshore bipolar HVDC GIS. conductivity surface material ($\sigma$-SFGM) and permittivity distribution bulk ($\varepsilon$-FGM) are designed to coordinately regulate DC AC electric filed distributions, respectively. maximum field strength $\varepsilon$/$\sigma$-MFGM spacer decreases by 83.4% 18.5% under voltages. Meanwhile, flashover voltages increase about 34% 15%,
In bipolar high voltage direct current (HVDC) systems, gas-insulated metal-enclosed switchgear (GIS) may experience a combination of AC and DC voltages. To enhance the flashover spacers, this study proposes synergistic optimization method for electric fields (EF) spacers based on multi-dimensional functional gradient materials (MFGM), which incorporates both dielectric constant <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varepsilon$</tex>...
This study discusses a multi-dimensional parameter design of functionally graded materials for spacers in high voltage direct current gas insulated transmission lines (HVDC GIL). Based on basin-type spacer, effects surface conductance ($\sigma$-SFGM) the electric field distributions are investigated under stationary and transient conditions. Results show that $\sigma$-SFGM spacer can effectively regulate steady-state field, but regulation effect is limited when its time constant longer than...
This paper offers a simulation study on the application of novel approach to control electric field around basin-type spacer by combining permittivity functionally graded materials ($\varepsilon$-FGM) and superficially nonlinear conductivity (SNCM), namely multi-dimensional functional (MDFM). The distribution $\varepsilon$-FGM is designed iteration optimization algorithm, epoxy/SiC composites with 30 60 phr (parts per hundred) doping contents are assigned as coating two SNCM spacers, SNCM30...
This study discusses the approach of adaptatively regulating surface charge and electric field distributions by nonlinear conductivity materials. Three groups (SNC) spacers, namely SNC30, SNC60 SNC90, were prepared coating epoxy/Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> spacers with epoxy/SiC composites 30, 60 90 phr doping contents. Experimental results show impressive...
In this study, a downsized DC-GIL model is applied to investigate the surface charging and discharging characteristics of basin-type spacer in 0.1 MPa SF <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> gas. Under low electric field, charge accumulation dominated by bulk conduction spacer. As voltage increases, gas ionization occurs localized strong field around high electrode, taking over dominant position. Flashovers typically develop...