In this article, electrical tree morphological features in epoxy resin under tensile and compressive stress are investigated. The applied varies from 0 to 30 MPa, whose direction is perpendicular the needle electrode. obtained results show that accelerates growth, especially parallel stress. With increasing stress, both length corresponding accumulated damage decrease first subsequently increase. By comparing distribution vertical directions, it found mainly propagates ground electrode A...

Interface charges are easy to accumulate between two different dielectrics with various characteristics, which may cause accelerated degradation of insulation systems. Ethylene-propylene-diene terpolymer (EPDM) is used mainly for HVDC cable joint, the most vulnerable part system because interface. Particles nonlinear conductivity can be doped into polymer matrix modify interface charge behaviors through altering under combined stresses. In this paper, silicon carbide (SiC) particles were...

The dielectric properties of epoxy resin mainly depend on its microstructures, especially the curing degree. In this article, reaction process diglycidyl ether bisphenol A (DGEBA)/methyl hexahydrophthalic anhydride (MHHPA) system is studied by differential scanning calorimetry, and samples with different degrees are prepared regulating temperature time. evolution microstructure during crosslinking simulated molecular dynamics simulation. It found that effect degree can be attributed to...

Polyethylene is widely used as insulation in power cables with its excellent electrical properties except low thermal conductivity. However, insulation-related problems pose a limitation on the ampacity of HVDC cables. Improving conductivity may contribute to heat dissipation cable system and enhance ampacity. In this work, order investigate effects improved temperature field single buried cable, numerical simulation model established by finite element method (FEM) calculated modified...

In this paper, space charge behavior over a large range of electric field and temperature, two kinds epoxy resins are investigated using an improved pulsed electro-acoustic method. Significant influence high temperature on the accumulation in found. Hetero starts to build up at 80 °C under 120 kV/mm for amine-type hardener cured (EP-AM), while 140 60 anhydride-type (EP-AH). The accumulated increases with increasing temperature. maximum enhancement local is 135 123 % EP-AM EP-AH,...

The electric field distribution is determined for the design and long-term performance of bushing yet gets complicated when coupled with temperature due to highly temperature-dependent conductivity insulation. An electrothermal coupling model established based on a ±800 kV converter transformer valve-side bushing. measured insulation adopted fitted. inside condenser core under influence was investigated, related mechanism analysed, considering different voltage forms, loading currents,...

A multi-physics simulation model of the tri-post insulator in ±800 kV GIL laid horizontally is established to study effects gas convection on surface charges and electric field distribution. Results show that density together with dielectric strength around upper post reduced over 11% under generated by load current. The larger temperature gradient (29 K) along lower accelerates more charge injection through buck conduction distorts bottom post, which 19.4% higher than post. insulation...

The galloping of iced transmission line under extreme weather conditions, will lead to significant electrical faults and structural damage, is becoming a serious issue that threatens the safe stable operation power grid. In this paper, simulation model 10 kV insulated overhead established based on finite element method, effects various influencing factors behavior aerodynamic characteristics are investigated analyzed. results show stability lines poorest, when wind speed between 7 15 m/s...

Discharge failure mechanism of the cable buffer layer is investigated in this paper by analysis causes and characteristics partial discharge (PD) behaviours case failure. The obtained results show that both volume resistivity surface resistance increase as relative humidity elevated. It found electric field distribution inside distorted when there poor contact condition aggravated with finite element analysis. PD shows intensity closely related to state layer, hence latter can be reflected...

The addition of accelerator reduces the curing reaction temperature, changes process, and affects morphology crosslinking structure, which would lead to difference in dielectric properties epoxy resin. In this study, behaviors diglycidyl ether bisphenol A (DGEBA)/methyl hexahydrophthalic anhydride (MHHPA) were investigated with respect contents accelerator, Tris-(dimethylaminomethyl) phenol (DMP-30). behavior resin was studied by differential scanning calorimetry (DSC), it found that system...

In this article, aramid fiber surface is treated by dielectric barrier discharge (DBD) plasma, and various reinforced epoxy composites (AFRCs) are prepared to investigate the effects of plasma modification on mechanical properties. It found that treatment could change roughness active chemical groups content surface, which beneficial improvement interfacial bonding strength between resin. After appropriate time with 2 min Argon flow rate L/min, conductivity, loss, integration charge...

Abstract In this paper, three epoxy resin systems commonly used in power equipment are prepared to obtain cross‐linked networks with structural differences. The relationship between microscopic structures and dielectric properties of resins is investigated discussed. Experimental results show that the polarization conductance losses inhibited anhydride‐cured methyl groups. molecular dynamics (MD) simulation shows rigid anhydride (such as groups) play a major role reducing local segment...

To investigate the effect of thermal aging on liquid silicone rubber (LSR) used for dry-type transformers, various LSR samples are aged at different temperature 225, 250, 275 and 300 °C, with time 24, 48, 96, 336 504 h. The experimental results show that process can be roughly divided into two stages depending result competition between crosslinking reaction fracture reaction, as evidenced by FTIR. In early stage, DC conductivity integral charge Q (t) decrease, while breakdown strength...

Abstract High thermal conductivity filler is an important solution to improve the heat dissipation of insulating materials. However, poor interfacial compatibility inevitable factor that inhibits improvement and has a negative effect on dielectricproperties composites.Plasma can generateabundant active radicals graft surface fillers, which great potential filler-matrix interface. In this work, plasma bubble treatment method based discharge in bubbles proposed efficiently strip multilayer...

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...

Gas-insulated switchgear (GIS) cable terminations have higher failure rates at low temperatures. In this study, a 110-kV full-size GIS termination model is developed to investigate mechanism. The coupling characteristics of the thermal and mechanical stress distributions in are analyzed. A pressure-controlled interfacial discharge experimental setup established, partial damage features tracking investigated for different interface pressures. At temperatures as −40 °C, pressure distortion...

The poor interfacial adhesion between aramid fiber and epoxy resin is the main issue affecting dielectric properties of fiber-reinforced composite (AFRC). In this paper, bioinspired polydopamine (PDA) coating method used to modify surface, which already activated by plasma treatment. Various fiber/epoxy samples are prepared, effects PDA concentration on studied. It indicated that bonding strength could be improved, thus contributing higher mechanical enhanced properties. Results show DC...

Epoxy resin has been widely used as dielectric material in irradiation environment, such nuclear power plants, aerospace equipment and superconducting apparatus. This paper investigated the effects of different electron beam doses on trap distribution epoxy under repetitive pulse voltage. Samples were irradiated at room temperature (20 °C) air by high energy 7.5 MeV with density ranging from 0.35 to 0.45 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

In this paper, a high-field magnet experimental system is setup to investigate the dielectric properties of epoxy resin in presence high magnetic field. An asymmetric ferromagnetic electrode used build gradient field and its effect on tree characteristics resin. Influence mechanisms are discussed through combining results simulation calculation. Experimental show that electrical trees more easily be initiated spread rapidly The conductivity increases with increase strength due energy level...

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 (EP)/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> spacers with EP/SiC composites 30-, 60-, 90-phr doping contents. Based on a downsized direct current...