Transformer mineral oil has been replaced by alternative oils such as synthetic and natural esters due to their biodegradability environmentally friendly nature. This paper presents performance of coconut an alternative. Generally, the other oils, high conductivity presence free fatty acids. In this study, three different types samples consisting virgin, copra RBD (refined, bleached deodorized) were initially tested frequency dielectric spectroscopy (FDS) measurements see how was improved...

Aging of transformer paper insulation is commonly investigated through indirect measurements conducted in the oil, e.g. furanic compounds. In addition to conventional indicators, recent investigations showed that alcohols like methanol and ethanol oil could be used as aging indicators. This focuses on applicability these new indicators a novel, gas-to-liquid (GTL) technology based an accelerated laboratory experiment. The experiment was at 120 °C for up 280 days. A mineral also tested...

The applicability of using 2-furfural (2-FAL) and methanol as aging markers for synthetic ester impregnated paper insulation was investigated through laboratory experiments at temperatures 80, 100 120 °C. Methanol in the increased linearly with until degree polymerisation (DP) reached 400. During this period concentration oil higher than that 2-FAL, which proved concept to indicate early ester. However, rate increase against reduction DP about three times seen mineral oil. This is due a...

Synthetic ester has emerged as an alternative in applications where mineral oil traditionally been used. Furthermore, their new areas such converter transformers and battery energy storage systems are currently being investigated. Conductivity of insulating materials is a crucial parameter for applications. This paper investigates the impact electrical field on conductivity synthetic through combination experimental simulation studies. The results indicated short-term increases while...

Abstract Applying environmentally friendly ester liquids in high‐voltage direct current (HVDC) converter transformers is a technological ambition that requires research on their performance under DC voltages. This paper researched liquid‐impregnated Kraft through experimentally investigating space charges and dielectric properties HVDC fields. The study focused mainly the influence of cellulose degradation. Hence, papers different degree polymerisation impregnated with fresh liquid mineral...

Paper ageing is an irreversible process, which has made paper insulation a lifetime determining factor for transformers. Chemical indicators in oil such as carbon oxide gases and 2-FAL, are used to indicate the state of it difficult obtain samples measure DP or tensile strength. Methanol amount was recently found be early-ageing indicator paper. In this study, headspace gas chromatography mass spectrometry setup developed methanol transformer oil. This consists auto sampler with tight...

Managing a large fleet of ageing assets has become technical challenge faced by many electricity utilities in developed countries. Asset managers are increasingly interested techniques that can help extend the useful lifetime transformer. Oil regeneration is one such techniques. In this paper, oil experiments were performed on 6.4/0.4 kV retired distribution transformer to investigate effect improving paper conditions. was conducted two stages, with first stage aimed at ‘cleaning oil’ and...

• MD simulation is used to study impact of graphene on arc erosion resistence Cu. Arc circuit breaker contacts was simplified as ion bombardment. Graphene can dissipate the energy transferred from incident ions by a shock wave. prevent sputter recoiled Cu atoms. Gr-Cu has less sputtered atoms and shallower pits surface than pure Molecular dynamics been applied mechanisms through which protects in Cu-W arcing contacts. The positive bombardments cathode surface. Sulphur were while number ions,...

Ageing assessment of transformer paper insulation is important due to its irreversible ageing nature. Due the poor accessibility samples in field transformers, large efforts were made seek for chemical parameters oil indicate ageing, e.g. furanic compounds and dissolved carbon oxides. In recent years, alternative including methanol ethanol proposed be related with ageing. this study, a laboratory experiment was conducted at 120 °C an inhibited mineral ordinary kraft paper. Methanol measured...

Electric field distortion caused by space charge accumulation is one of the challenges in development insulating liquid immersed converter transformers and battery energy storage. This paper studies impact temperature moisture content on synthetic ester through an improved computational model incorporating time-development permittivity liquid, test results indicated highly accurate simulation electric distribution can be produced compared with previous model. Charge mobility density were...

The present study aimed to investigate the effects of graphene/metal interface on elastic properties Cu and W matrices over a wide range temperatures through molecular dynamics (MD) simulations. Results showed that addition graphene can improve their Young's moduli, with higher enhancements observed at fractions. load transfer mechanism was employed analyse reinforcing effect in metal matrices, rates were subsequently calculated. strengthening matrix increase significantly rising...

This paper presents performance comparison of coconut oil as an alternative liquid insulation for transformer mineral during ageing and under simulated electrical thermal fault conditions. In the study, 6 wet oil, dry samples were aged (each half sealed unsealed with inclusions Cu, Al, Fe Zn metal substances) inside oven at 120°C. Six sample sets taken out three different intervals i.e. 2, 5 7 weeks tested by visual inspection (color), chemical tests (interfacial tension, acidity, DGA)...

Coconut oil has been considered as an alternative choice for power transformer liquid insulation. This paper presents ageing aspects of coconut in comparison to that oil. Wet and wet dry was aged sealed unsealed conditions at 120°C. Variation color, interfacial tension, acidity, breakdown voltage frequency dielectric spectroscopy observed during different aging period 2, 4, 7 weeks. In the process, acidity conductivity levels increased. However, its strength considerably high compared...

Moisture in transformer insulation is a topic of major interest to power system equipment operators. plays large role the degradation within transformer, impacting on longevity and failure rate this crucial asset. Therefore, understanding how moisture behaves has been focus many studies. One particular matter that can occur during high-temperature events formation bubbles water vapor which are released from cellulosic paper wrapped windings. During such events, presence these could lead an...

Low molecular-weight acids (LMA) are by-products of and catalysts to transformer paper ageing. Their concentration can be well below 0.1 mg KOH/g. There has been no standard procedure measure control these at low acidity levels. In the present work, a technique using water separate an LMA from two types liquids, mineral oil synthetic ester, was proposed its effectiveness studied. Two vessel configurations, Erlenmeyer flask (EF) gas-tight syringe (GTS), were tested for important step...

The liquid-solid insulation system of converter transformers used in line commutated based HVDC systems is subjected to combined AC and DC stresses. In addition, the voltage polarity reversal when direction power flow reversed. Under voltage, space charges are injected generated insulating materials then accumulate at interfaces. Thus, during reversal, liquid a high electric field that may result electrical breakdown. This paper studies charge behaviors ester liquids as potential alternative...

Ageing assessment of transformer paper insulation is commonly conducted through measurement different chemical indicators in oil such as carbon oxide gases and furanic compounds [1]. Apart from these conventional ageing indicators, recent research success has shown that methanol ethanol transformers can also be used to indicate the degradation [2].

For nearly four decades 2-furfural (2-FAL) in transformer oil has been used as a chemical marker to indicate the ageing state of paper insulation. Nevertheless, it always challenge define an acceptable limit for 2-FAL due issues related non-uniform temperature distribution transformers, stability and its partitioning between liquid solid Therefore, users try combine laboratory findings, operational experience post-mortem analyses together predicting insulation through content oil. Due...

Bubble formation in transformers could result severe consequences leading to power outages and huge financial losses. There is an increased risk of bubble the future due increasing load demand much higher loading fluctuations. The process transformer insulation has been studied for decades water content paper addressed as most influential impact parameter. However, results from common insulating material combination Kraft mineral oil vary widely a meaningful comparison other parameters or...

Ageing assessment of cellulose insulation in a transformer is normally conducted through indirect measurements chemical markers oil. In addition to the conventional paper ageing indicator 2-FAL, methanol oil was proposed as an additional provide early information. Relationships between and concentration indicators could be affected by type due stability partitioning issues. Therefore it important investigate suitability for alternative insulating oils. This shows results laboratory...

Acidity has been recognised to be an excellent marker of the transformer insulation system. In recent decade, a sub-group acids, known as low molecular weight acids (LMA), have identified cause acid catalysed degradation paper insulation. Due unavailability standard method, LMA in oil is commonly measured through water-extraction process where extracted into water prior titration. This contribution investigates effects some key parameters extraction including stirring speed, duration and...