It is generally accepted that the presence of bubbles severely degrades electric strength liquid dielectrics, but influencing factors and mechanisms have yet to be elucidated. Dynamic behavior, partial discharges (PDs) inside bubbles, their effects on breakdown transformer oil are investigated experimentally theoretically in this study. The results show that, under a nonuniform field, does not significantly affect PD inception voltage (PDIV) (BV) liquid, as migrate region with lower field...

Waste engine oil (WEO) and waste polyethylene (WPE) are two common wastes, which easy to pollute the environment. As primary material in road construction, natural asphalt is a non-renewable energy source vulnerable ultraviolet (UV) radiation during service life. It results degradation of pavement performance. In this paper, 22 wt % 82 WEO WPE were used modify asphalts UV aging simulation experiment was carried out. The physical parameters before show that containing 42 62 mixture (42 + WEO)...

Snow and ice accumulation on asphalt pavement can increase the risk of traffic issues. The traditional method removing snow manually or mechanically from road surface is time-consuming labor-intensive. Another common spraying salt pollutes surrounding environment. To overcome these issues, objective this study to a polyurethane superhydrophobic coating characterize its anti-icing properties. A (PSC) using carbon nanotube particles (CNTPs) was developed in lab. contact angle roll tests,...

Under temperature and moisture combined, bubbles will be formed in oil-impregnated paper/pressboard (OIP/OIPB). Although many studies have been done to understand the thermo-induced bubble phenomenon OIPB, formation mechanism is not, let alone its effect on discharge characteristics insulation performance of OIPB. In this article, phenomena mechanisms thermally induced bubbles, their effects partial (PD), breakdown OIPB are investigated. The results show that inception (BIT) decreases...

Abstract Although many studies have been done and advanced progress has made in understanding partial discharge (PD) behavior the void, this is not case firinception of PD, especially its stochastic nature. The statistical behaviors PD inception voltage (PDIV) time delay (PDTD) inside void were investigated study through repeated tests to observe nature inception. results show that PDIV PDTD are highly dispersed obey Weibull exponential distributions, respectively. significant dispersion can...

Reactive dyes containing cationic groups have great potentiality as novel dyes, which can be applicable to one-bath dyeing of wool/acrylic blended fabrics. In this work, four heterocyclic reactive were designed by using m-aminophenyltrimethylammonium salt or N-(2-aminoethyl) pyridinium chloride groups, N, N-diethyl-1,3-benzenediamine a coupling component, 2-amino-6-methoxybenzothiazole, 2-aminobenzothiazole 3-amino-5-nitrobenzoisothiazole diazo components. These based on benzothiazole...

Bubbles in oil-paper insulation migrate and may finally accumulate, posing enormous risks. Accurate simulation of bubble migration accumulation is vital importance. The cross-scale nature micrometer-millimeter movement meter-scale structures makes macroscopic methods often ignore the microscopic details bubbles, which calculation accuracy hard to guarantee. In this study, dynamics were analyzed by Euler-Lagrange approach, distributed interaction on interface was simplified lumped interfacial...

Abstract Power systems grapple with the challenges of high load rates and intermittent new energy sources integration. Transformers, as vital equipment, employ oil/pressboard (oil/PB) insulation. Uneven moisture distribution in this insulation can jeopardise safety thresholds, necessitating precise assessment for grid stability. A novel mathematical model, adsorption–desorption porous media transfer (ADP‐MoT), is presented. This model incorporates adsorption desorption processes within...

In order to improve the EV (Electric Vehicle) energy efficiency and explore heating performances of automotive heat pump under low ambient temperatures, an integrated AC/HP (Air Conditioning/Heat Pump) system was established applied in a compact EV. Environmental chamber employed produce target conditions scroll compressor used raise operating speed. Refrigerant R134a then R407C were tentatively served as working fluids. temperature range -15∼0°C, near on-field behaviors experimentally...

Abstract Operating experience has shown that characteristic gases can be found in oil‐immersed power transformers and high‐voltage reactors under strong vibration without discharge or thermal faults occurring. This will cause misdiagnosis of Dissolved Gases Analysis (DGA). In this study, generation characteristics mechanism transformer oil dependent on are investigated. The results show there is a pressure threshold makes such as hydrogen (H 2 ), methane (CH 4 ethylene (C H ethane 6...

An AC-DC combined voltage is applied to the oil-pressboard insulation near valve side during operation of a converter transformer. To study breakdown characteristics an under such voltages, typical plate electrode structure was employed in laboratory conduct test on insulation. The electrical field distribution and DC contents transformer oil pressboard composite were simulated by their dielectric parameters. strength decreases with increase content voltage, whereas that increases. For...

The strong dependence of electrical explosion wires (EEW) on wire dimensions is demonstrated experimentally from three perspectives: characteristics, spatial structures, and nanopowder properties. Electrical characteristics EEW were explored by measuring current voltage waveforms exploding 20–100 μm-diameter 2–10 cm-long in argon gas. discharge mode, energy deposition, breakdown analyzed based the calculation several parameters. Laser-based diagnostics multi-frame photographs used to obtain...

The measurement of ac/dc hybrid electric fields in converter transformers is important for the verification field calculation model and insulation optimization. Electro-optical (EO) sensors have obvious advantages measuring strong fields, but their response characteristics mechanisms under action are not fully understood by researchers, which restricts a wide application sensors. In this article, we first describe an improved dual-beam structure, enables us to measure both ac dc oil...

Moisture in oil–paper insulation has a great influence on performance, and moisture distribution is always uneven. In this study, the of surface flashover channel position time under dc voltage different distributions were examined by statistical methods. The experimental results positions fit normal, lognormal, gamma, Weibull distributions, goodness was evaluated correlation coefficient Kolmogorov–Smirnov (K–S) testing. showed that best Normal distribution. A hypothesis test double sample...

The breakdown and streamer behavior in double-layer oil-paper insulation under impulses of varying front time were investigated this study to determine the prebreakdown process insulation. relationships between times characteristics impulse-polarity-dependent variations observed. complete impulse precise role assessed as per initiation propagation based on emitted light signals shadow images. re-initiation streamers non-first oil gaps was determined be key factor as-dominated by applied...

Abstract In order to solve the problem between low power of Internet Things devices and high cost cryptography, lightweight cryptography is required. The improvement scalar multiplication can effectively reduce complexity elliptic curve (ECC). this paper, we propose a fast formula for point septupling on curves over binary fields using division polynomial multiplexing intermediate values accelerate computation by more than 14%. We also algorithm based step multi-base representation halving...

High entrance capacitances of ultrahigh-voltage (UHV) transformers make it difficult to generate impulses with standard front time during the lightning impulse tests. In this paper, we discuss feasibility examining longitudinal insulation design a transformer via longer than value. We consider following features: transient voltage distributions and characteristics insulation. The voltages two UHV windings are measured capacitive sensor under different times. results demonstrate that applied...

When an external short-circuit fault occurs, the transformer windings will be subjected to electromagnetic force, and accidents such as winding tiltiing buckling occur, which seriously endangers operating safety of power system. At present, a in multiple continuous transposed conductors (CTCs) wound parallel is widely used transformers. In order suppress circulating current, transposition structure generally adopted, changed. This affect leakage magnetic field distribution, then change...

An inductive wireless telemetry circuit for implantable cardiac pacemakers is presented in this paper. internal coil the titanium case transmits detected data into of outside programmer. The configuration and commands from programmer are sent to pacemaker through same pair coils save volume system. In order realize reliable low-power communication housing, OOK modulation with a carrier frequency 128 KHz adopted demodulator realized simply diode-based rectifier, while external demodulation...