A5064033567- High voltage insulation and dielectric phenomena
- Dielectric materials and actuators
- Lightning and Electromagnetic Phenomena
- Power Transformer Diagnostics and Insulation
- Advanced Sensor and Energy Harvesting Materials
- Electrical Fault Detection and Protection
- Aerosol Filtration and Electrostatic Precipitation
- Electrostatic Discharge in Electronics
- Plasma Diagnostics and Applications
- Conducting polymers and applications
- Thermal Analysis in Power Transmission
- Fuel Cells and Related Materials
- Power Line Communications and Noise
- Innovative Energy Harvesting Technologies
- High-Voltage Power Transmission Systems
- Superconducting Materials and Applications
- Semiconductor materials and devices
- Advanced Battery Technologies Research
- Particle accelerators and beam dynamics
- Ferroelectric and Piezoelectric Materials
- Power Systems Fault Detection
- Tree Root and Stability Studies
- Electromagnetic wave absorption materials
- Plant Water Relations and Carbon Dynamics
- Advanced Battery Materials and Technologies
University of Connecticut
2019-2024
UL Solutions (United States)
2023
University of Tehran
2019
A paradigm-shifting design strategy is demonstrated that unifies the treatment of electronic and conformational properties polymer dielectrics for concurrent high electric field elevated temperature harsh conditions.
Polymer-based dielectrics are essential components in electrical and power electronic systems for high density storage conversion. A mounting challenge polymer is how to maintain their insulation at not only electric fields but also elevated temperatures, order meet the growing needs renewable energies grand electrifications. Here, a sandwiched barium titanate/polyamideimide nanocomposite with reinforced interfaces via two-dimensional nanocoatings presented. It demonstrated that boron...
Charging of insulators modifies local electric field distribution and increases potential threat to the safety gas insulated equipment. In this paper, surface charge tailoring techniques are classified reviewed by introducing a Dam-flood model. Technical solutions different methods compared discussed. The outlook suppress accumulation is recommended discussed based on industrial consideration. This paper serves as guide handbook for engineers researchers into study methods. Meanwhile, we...
Fundamental studies of potential candidates for DC electric power transmission in high temperature environment, including ETFE, FEP, PTFE, PI and PEEK, are carried out presented form the series papers containing space charge conduction as part I, partial discharge II, degradation surface breakdown III. In this part, at 20kV/mm was measured 25 °C with a thermal gradient 50 °C. The electrical conductivity fields ranging from 10kV/mm to 30kV/mm temperatures 200 experimental results showed that...
The first two parts in this series gave full analysis and discussion of five high temperature insulation materials, i.e. PTFE, FEP, ETFE, PEEK, PI over aspects space charge behavior, conduction property as well partial discharge, respectively. In part, the degradation surface breakdown properties are investigated related mechanism is discussed. results showed that due to stable formation C-F structures, PTFE FEP melted locally during arc erosion test, with no carbon element being...
Abstract Multi-layer ferroelectrets consisting of fluoroethylenepropylene (FEP) copolymer and open-porous expanded polytetrafluoroethylene (ePTFE) films exhibit stable internal electret charges, high piezoelectric coefficients heat resistance, making them promising candidates for wearable sensors or nanogenerators in body-area networks. Here, three- five-layer (FEP/ePTFE/FEP FEP/ePTFE/FEP/ePTFE/FEP) ferroelectret stacks were laminated poled a corona discharge. The resulting charge...
Utilizing hybrid electric propulsion systems in the next generation of aircrafts with elevated DC voltage level has raised concern about degradation insulation subjected to partial discharge at high altitude and harsh environment. In this work, surface behavior commonly used high-temperature materials aviation (FEP, ETFE, PEEK) under positive negative ramp was studied, including pulse waveform, frequency spectrum, PD count magnitude. Pressure changes as a significant factor influencing...
It is an urgent requirement to suppress surface partial discharge (PD) activities of dielectrics for modern electrical and electronic devices. Here, we introduce a method mitigate the PD in manner tailoring insulation conductivity. A coating with conductivity ranging from 10−13 10−10 S developed regulate charge migration vicinity triple junction effectively activity. The excellent performance this provides approach suppression at DC voltage, which has great application potential design...
Flexible polymer dielectrics which can function well at elevated temperatures continue to be significant in harsh condition energy storage. However, state-of-the-art high-temperature polymers traditionally designed with conjugated structures for better thermal stability have compromised bandgaps and charge injection barriers. Here, we demonstrate a self-assembled polyvinyl alcohol (PVA)/montmorillonite (MMT) coating impede carriers injecting into the polyimide (PI) film. The anisotropic...
In this study, electric field distribution of cable joints under steady state voltage and transient conditions, i.e. lightning impulse polarity reversal, was investigated using electrothermal simulation. Field grading techniques including geometric with materials were considered as the methods to tailor local based on an electro-thermal model 80kV joint in COMSOL Multiphysics. The results show 6.5 kV/mm 6.9 decrease amplitude at critical point interface presence FGM reversal condition, respectively.
Flexible ferroelectret-polymer films are piezoelectric due to macro-dipoles that consist of charge layers with opposite polarity across deformable internal cavities and can thus be suitable for wearable energy-harvesting devices. 3D printing ferroelectrets could increase the design variability cavity structures, enhance performance extend application possibilities. In this work, three polypropylene (PP) ellipsoidal cavities, but different in porosity sample thickness were printed by means...
PCB layouts with different polygon shapes and insulation distances were prepared their surface flashover voltage subjected to ramping rates measured at temperatures low gas pressures for emulated high-altitude conditions. The dependence of the on effects pressure, distance, temperature, shape was studied. Modulation efforts which include tailoring local conductivity topography modification performed increase PCB, related mechanism results showed that rate plays an important role in...
The complicated electrical installation system in airspace environment is exposed to harsh operation condition such as high conductive and low pressure atmosphere which deteriorate the insulation between different parts. elevated DC voltage level power distribution of hybrid propulsion systems has raised concern about risk degradation due partial discharge insulated wiring cabling system. Since widely accepted systematic procedure for PD studies including test method analysis strategy at not...
The innovation of materials with disruptive properties can be efficiently guided by improved physical understanding material design principles. a polymeric insulation depends on the desired requirements specific application, which, in case DC cable insulation, stated terms following properties: controlled electrical conductivity, low space charge accumulation and high breakdown strength. Full characterization detailed these as well their correlation balance may bring ability to engineer...
Fault current limiter (FCL) is a kind of device with current‐dependent impedance that has low in normal state power system, and high during fault condition. Among all classes FCLs, the saturated iron‐core FCL (SICFCL) practically most favourable one nowadays. In this study, numerical method for design cost optimisation SICFCLs presented. It uses set constraints to ensure desirable operation SICFCL based on its electrical magnetic characteristics. For calculations optimisations, GAMS software...
The role of space charge under DC electric field on aging cable insulation has been proven. In providing the and temperature are two effective factors. This paper investigates influence making in a special group materials used high (HT) application. These insulations usually normal field, but effect their can be vital. For this, list commercial HT were selected results three different thermal conditions from room (RT) to 200°C compared. To analyze some electrical indexes like amplitude...
For the reliable utilization of HVDC interconnections, joint/termination, as keystone elements have to be engineered with superior performance and reliability. The use insulating material in cable interconnections different from that insulation results dielectric/dielectric interface joint. Under DC stress, field distribution multi-dielectrics depends on differences constitutive parameters, conductivity permittivity, profile is complex difficult predict under thermal gradient. In this paper,...
High-temperature insulation materials have been used extensively in power systems from generation and conversion components like high-temperature steam turbines to transportation space, marine rail industries due their excellent thermal, mechanical dielectric properties as well light weight. However, electrical characteristics of these for abovementioned applications not fully understood. In addition, needs hybrid compulsion system is pushing rapidly the voltage ratings cabling a level that...
Solid-state high-voltage direct current (HVDC) circuit breaker safeguards the power system of more-electric aircraft against fault transients, within which components are soldered in print boards (PCB) for operation at low air pressure and limited space. The electric field near can be influenced by insulation polarization, flashover could induced ramp voltage. It is great significance to study characteristics PCBs DC In this paper, PCB layouts with different polygon shapes distances were...
A model DC material based on ethylene propylene rubber (EPR) including the pure EPR and EPR-based nanodielectrics incorporated with two different nanoclays, Kaoline Talc, under operational conditions was investigated. The include a 20 kV/mm electric field at 25 °C, 50 °C thermal gradient, 40 gradient polarity reversal. Space charge distribution, surface potential, electrical conductivity were measured to characterize interpret discrete dynamics in bulk interface of three samples....