Transformer oil-based nanofluids with TiO2 semiconductive nanoparticles exhibit substantially higher AC and positive impulse breakdown voltage levels than that of pure transformer oils. Thermally stimulated current method (TSC) pulse electroacoustic technique (PEA) have been used to measure charge trap transportation characteristics oils nanofluids. It is found electron shallow density decay rate are greatly increased in nanofluids, i.e., fast electrons may be converted slow by trapping...

Surface creeping discharge at solid-liquid interface is regarded as one of the reasons for oil-immersed transformers failure. In order to restrain surface discharge, we investigated effects TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanoparticles on and flashover characteristics oil/pressboard under AC impulse voltages. Partial tests (OPs) nanofluid/- pressboard (NPs) were carried out. The results show that can improve both...

Recent experiments have shown that some nanoparticles can influence the breakdown strength of transformer oil under lightning impulse voltage. To reveal working mechanism, this paper presents an experimental study on effect TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and prebreakdown streamer propagation process in oil-based nanofluid both positive negative The test results verify modification has a distinct polar effect: voltage...

Graphite-phase carbon nitride is regarded as a highly promising piezoelectric catalyst, yet its interlayer and in-plane charge transfer capabilities pose significant limitations to application. In this study, Cl, K co-modulated was synthesized via the molten salt method. The introduction of which exhibits an electron-withdrawing effect, breaks symmetry crystals enhances structural polarity. Meanwhile, intercalation reduces localized states electrons, expands π-conjugated system, serving new...

Considering the complexity of physical model wildfire occurrence, this paper develops a method to evaluate risk transmission-line corridors based on Naïve Bayes Network (NBN). First, data 14 wildfire-related factors including anthropogenic, physiographic, and meteorologic factors, were collected analyzed. Then, relief algorithm is used rank importance according their impacts occurrence. After eliminating least important in turn, an optimal assessment for was constructed NBN. Finally, carried...

With the intensification of global climate change, frequency wildfires has markedly increased, presenting an urgent challenge in assessing tripping failures for power systems. This paper proposes innovative method to evaluate spatial wildfire-induced risk transmission lines based on a flame combustion model. Firstly, Bayes theory is employed assess probability wildfire occurrence. Subsequently, Wang Zhengfei’s model utilized estimate potential height along corridor. Thirdly, insulation...

Nanotechnology provides a new way to improve the insulating properties of traditional dielectric materials. In this study, three types mineral oil based nanofluids were prepared by suspending Fe3O4, TiO2 and Al2O3 nanoparticles all which surface modified oleic acid. The inception voltage, stopping length propagating velocity streamers in under positive lightning impulse voltage experimentally studied. It is found that can restrain initiation propagation processes transformer depending on...

The insulation of mineral oil-based nanofluids was found to vary with different concentration level nanoparticles. However, the mechanisms behind this research finding are not well studied. In paper, were prepared by suspending TiO2 nanoparticles weight percentages ranging from 0.0057% 0.0681%. breakdown voltage and chop time observed under standard lightning impulse waveform. experimental results show that presence increases oil positive polarity. enhancement strength tends saturate when...

Transformer pressboard impregnated in mineral oil modified by nanoparticles (nanofluid) exhibits substantially higher AC and DC breakdown voltage than that of the pure oil-impregnated (OP). Charge transport decay characteristics both pressboards were measured pulse electroacoustic technique. It reveals nanofluid-impregnated (NP) has a more uniform internal electric field charge rate compared to OP, which is caused an increase shallow trap density NP related difference structures, based on...

In order to improve the electrical characteristics of transformer oil-impregnated pressboard, oil-based nanofluids were used impregnate pressboards. It is found that nanofluid-impregnated pressboard (NP) exhibits substantially higher AC and DC breakdown voltage than pure (OP). Pulse electroacoustic measurement (PEA) was carried out study difference space charge distribution decay characteristic in OP NP. has demonstrated NP a more uniform internal electric field, which caused by transport...

This paper presents experimental research on creeping discharge characteristics of TiO2 nanofluid-impregnated pressboards (NPs) under sustained ac voltage. It was found that NPs possess higher resistance to than pure oil-impregnated pressboard. The results permittivity and surface charge accumulation decay reveal the modification nanoparticles can not only make electric field more uniformly distributed at interface nanofluid/pressboard due a better matching in but also significantly increase...

Limited by the time intervals of passing territory polar-orbiting satellites, it is impossible to uninterruptedly monitor wildfire occurrences in power transmission line corridors using satellites. In this paper, a monitoring technique based on Himawari-8 geostationary meteorological satellite was proposed. Considering influences solar elevation angle, non-vegetation pixel and cloud identification precision, an adaptive dynamic method proposed identify fire-points. This has been applied...

Once a wildfire occurs near the transmission line, continuous burning of would trip line with low success rate reclosing. In this paper, data mining tools including Support Vector Machine(SVM), Back Propagation Neural Network(BPNN) and Random Forest(RF) were used to predict events wildfire-induced trips. As number trips are much less than that wildfires, SMOTE, undersampling EasyEnsemble balance data. The results showed performs best among three data-balance approaches model established by...

Abstract In this paper, a two-dimensional axisymmetric numerical model of streamer discharge in alternative natural ester liquid and conventional naphthenic oil under positive sub-microsecond impulse voltage is proposed. The based on the charge drift-diffusion approximation divergent electric field. Simulation shows that propagation divided into two stages: stage I with small velocity 0–0.91 km s −1 II rapidly rising up to 213 . ester, gradually slows down from 4.84 2.11 field at head ranges...

Facing towards the Carbon Neutrality goal by 2060, renewable energy sources are boosted in China past decade. Either these renewables or power systems sensitive and vulnerable to natural disasters, such as wildfire typhoon. In this paper, a fire spot identification algorithm is proposed for disaster occurred transmission line corridors based on Fengyun-3E (FY-3E). It mitigates effect of large observation solar zenith angle, well changes satellite views, infrared channel detection. And cloud...

In order to improve the wildfire prevention capacity of transmission lines, a risk assessment method for transmission-line corridors based on Weighted Naïve Bayes (WNB) is proposed in this paper. Firstly, importance 14 collected types wildfire-related factors analyzed information gain ratio. Then, optimal set and most accurate sampling table are constructed by deleting lowest one one. Finally, performance WNB model compared that NB BNW models according ROC curve visualization. A total 76.36%...

With the rapid development of real estate market, more and explorers prefer to choose market outsourcing speed up marketing realize return capital. Risk will happen inevitably in process outsourcing. This paper summarizes analyzes risk produced by using qualitative research method induction deduction based on life-cycle theory, constructs assessment model matrix Voting Theory. Taking a typical project for example, it applies assess key risk. The result is conformed realistic situation, which...

Wildfires, occurred in transmission line corridors, seriously affect the security and stability of power grids. In order to reduce effects wildfire on grids, a logistic regression (LR) model was employed assess risk distribution occurrences corridors. Guizhou Province which locates at south-west China taken as study region. An inventory dataset including 14 wildfire-related variables historical were assembled. After multicollinearity analysis variables, occurrence probability wildfires...

Ice accretion on high voltage power lines is a severe problem for network and it can cause insulator flashover, wire breakage tower falling down. In the present work, hydrophobic aluminum cable steel reinforced was prepared with simple chemical etching modified fluoroalkylsilane (FAS) coating. Only partial area of sample covered by some isolated ice crystal form long icicle gradually when sprayed supercooled water droplet under low temperature condition. As common reinforced, an intact layer...

An application research work had improved a Bayesian network rule function of Pro/3 (a production system type expert shell).This improvement makes it possible for the same rules to ask evidence such as evaluated probability or certainty factor only once, which can avoid repetitive ask, adding simplicity and improving performance system.By using it, this also created transformer component fault diagnosis knowledge base model based on so that implemented an prototype system.The basic shows...