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The insulation paper is a crucial factor for evaluating the insulation status of transformers. The traditional evaluation methods for insulation paper are dissolved gas component content analysis (CO and CO2) and furfural (2‐FAL) content analysis in oil. The detection principle of the former leads to its low accuracy, while the field application effect of the latter is not ideal due to the easy oxidation of furfural and low content. Methanol, result of its good stability and high production compared with other marker products (CO, CO2, 2‐FAL) has been investigated as a novel marker for aging evaluation of transformer insulating paper in recent years. The results of the investigation indicated that there is a good correlation between the content of methanol in oil and the degree of polymerization under laboratory conditions, which reflected the insulation aging state of the transformer insulating paper more accurately. This paper summarizes the current research status of methanol formation mechanism, detection methods and aging evaluation in insulating oil, and points out the key problems to be solved and development prospects, hoping to provide relevant reference for aging evaluation of oil immersed power transformer. [ABSTRACT FROM AUTHOR]

The existing research on furfural analysis mainly focuses on the relationship between the furfural content in oil and the degree of polymerization (DP) of the paper, which are always obtained by accelerated thermal aging at high temperatures. However, the operating temperature of a winding is relatively low, approximately 60°C to 90°C. Thus, the relationship established at high temperature may be not suitable for the operating temperatures. In this research, aging tests of oil‐paper systems at different temperatures (from 100°C to 130°C) were carried out, with the DP, furfural content in oil and furfural content in paper being measured regularly to analyze the effect of temperature variation on the production and diffusion behavior of furfural in oil–paper insulation. The results show that temperature influences the production of furfural, i.e., there is no obvious difference in the amount of furfural produced by paper in the initial aging periods; however, a higher temperature results in more furfural being produced when the DP decreases to values below 600. An obvious diffusion process occurs after furfural is produced in paper in accelerated aging experiments, resulting in most of the furfural content remaining in the cellulose paper in the initial aging period. [ABSTRACT FROM AUTHOR]

The AC breakdown properties of Kraft paper, pressboard and the enamel insulation layer in riceoil, peanut oil and corn oil were investigated under both new and agedconditions. The ageing of paper insulators and the enamel insulation layer inoils with the open cup method was carried out at 130 oC for 500 h in an aircirculation oven. The puncture breakdown strength was determined by varying thenumber of layers and thickness of Kraft paper, while various electrode gapdistances were used to measure the surface breakdown strength. Experimentalresults show that the breakdown strength and the tensile strength of paperinsulators impregnated with these vegetable oils are comparable to that inmineral oil, and the surface breakdown strength of paper insulators is slightlyaffected by types of impregnating oils. The ageing significantly reduces boththe breakdown strength and the tensile strength of paper insulators ininvestigated oils. In addition, it was also found that the enamel layer invegetable oils withstood higher puncture breakdown strength than in mineral oil,and the ageing process significantly reduced the puncture breakdown strength ofthe enamel layer. This enamel layer was observed to markedly enhance the surfacebreakdown strength of pressboard. [ABSTRACT FROM AUTHOR]

The condition assessment of oil–paper insulation is a vital issue in transformer management. To investigate the effect of moisture content on the accuracy of the prediction model, accelerated ageing experiments were performed with different initial moisture content (IMC) in laboratory condition. Two types of multi-parameter lifetime prediction models, e.g. with and without consideration of IMC, were presented for comparison purpose. The authors found that a better accuracy for its prediction results could be achieved by establishing the prediction models with the consideration of IMC. Besides, models considering IMC have better economic feasibility than that without considering IMC(non-IMC) as its total cost is cheaper according to life cycle cost (LCC) calculations. In addition, failure probability based on the proposed prediction models was also calculated as a direct indicator for evaluating the oil–paper insulation status. [ABSTRACT FROM AUTHOR]

Near Infrared Spectroscopy (NIRS), as one of analysis technologies, has shown promisingly industrial applications for significant properties for recent decades such as fast response, preciseness, non-intrusion etc. Here, the authors employed NIRS coupled with a series of physical and chemical tests to assess the ageing condition of oil-paper insulation, which is responsible for the main insulation type of high-voltage power transformer. Among these procedures, the data analytic algorithms are of utmost importance to determine the evaluation precision. After plenty of trial-and-error, Savitzky-Golay (S-G) convolution was finally utilised to de-noise samples and improve the spectral data quality. The competitive adaptive reweighted sampling (CARS) was used to select the optimal wavelength combination of NIRS, which is found able to fully extract the effectively spectral information and reduce dimensions of spectral data. Based on the above-mentioned techniques, the quantitative analysis model of NIRS was established by partial least squares (PLS), which could synthetically process the spectral data and the degree of polymerisation (DP) of paper samples. The results indicated that compared with the traditional detection methods, the NIRS analysis is a powerful and informative tool to characterise the condition of oil-paper insulation without intrusion or damage to transformers. [ABSTRACT FROM AUTHOR]

Nomex insulation paper has been widely used in mining dry type transformer insulation because of its excellent performance. However, the injection of space charge can affect the electrical properties of the Nomex paper and accelerate the ageing process of the insulation system, which causes the insulation system failure or even breakdown. Therefore, it is of great practical value to study the space charge characteristics of Nomex insulation paper in different hygrothermal ageing conditions. The accelerated hygrothermal ageing tests of Nomex insulation specimens with different initial moisture contents were conducted. The space charge distribution of specimens impregnated by varnish were measured by the pulsed electro‐acoustic method at different ageing stages. Simultaneously, the space charge characteristics during polarising and depolarising phases were deeply analysed. Experimental results show that negative charges accumulate between the varnish‐paper interface in specimens near the anode. The number of negative charges gradually decreases with the increase of ageing degree. Under the influence of humidity, Nomex paper can be hydrolysed, which increases the trap density and trap level. Finally, a large amount of positive and negative charges in aged specimens would result in the distortion of the local electric field, which could decrease the breakdown strength of Nomex insulation specimens and be a threat to transformer insulation. [ABSTRACT FROM AUTHOR]

The service life of a transformer depends on the ageing degree of the internal oil–paper insulation. In order to reliably predict the remaining service life of oil–paper insulation for a single transformer, this study proposes a method based on monitoring the performance degradation data of oil–paper insulation. In this study, the remaining life prediction model of oil–paper insulation is established according to the Wiener stochastic process. The parameters of the model are iteratively updated by using the Bayesian rule and maximum expectation algorithm. The objective of remaining service life prediction of transformer oil–paper insulation is achieved. In the laboratory, multiple groups of oil–paper insulation samples undergo an ageing test at 130°C. Certain amount of performance degradation data is obtained by continuously monitoring the oil–paper insulation. Along with the prediction method of remaining life, the accuracy of the remaining life prediction of transformer oil–impregnated paper is verified when the model parameters are updated. This is a significant guiding factor for predicting the remaining life through the performance degradation data of the continuously operating transformer. [ABSTRACT FROM AUTHOR]

Study of alternate fluids for transformer and their combination with traditional ones is an interesting area of research. The intent of this work is to investigate the thermal ageing performance of ester oils (synthetic and natural), and mixed oil vis‐à‐vis mineral oil. All the samples were thermally stressed at 110, 140, 160, and 185°C for 2 weeks each. Dissolved decay contents in oil and linear thermal expansion coefficients of solid insulation have been studied using ultraviolet visible infrared spectroscopy and dilatometry analysis, respectively, as per ASTM standards. Change in functional groups of the insulation oils with ageing have been understood by Fourier transform infrared spectroscopy analysis. Additionally, diffusion of oil–moisture mixture into paper with ageing and the corresponding effect on dielectric strength of paper has been also examined using ASTM standards. It is observed that the use of synthetic ester (SE) and addition of SE to mineral insulating oil lead to improved performance of oil–paper insulation system with retarding the rate of degradation of the insulation system. [ABSTRACT FROM AUTHOR]

The oil‐impregnated transformer is an important part of the power system. The ageing degree of the internal oil‐paper insulation determines the service life of the transformer. The low frequency of the frequency domain dielectric spectroscopy can effectively characterise the ageing degree of transformer oil‐paper insulation. For accurately and quantitatively evaluate the aging state of oil‐paper insulation of transformer, the physical process of low‐frequency electrode polarisation is theoretically analysed in this work. Considering the polarisation of the low‐frequency electrode, the theoretical expression of the dielectric response of the equivalent XY model of the transformer is obtained. Meanwhile, to verify the rationality of the theoretical expression, the accelerated thermal ageing test of the oil‐paper insulation samples were carried out under laboratory conditions. The DC conductivity, ion mobility and FDS tests of oil‐paper insulation samples were tested on ageing 5, 10 and 15 days, respectively. The test results were combined with the theoretical expression of the low‐frequency dielectric response. It is found that the difference between the calculated result and the measured result is small. Therefore, the theoretical expression of the transformer equivalent XY model can be applied to calculate the dielectric parameters of the oil‐paper insulation at low‐frequency. [ABSTRACT FROM AUTHOR]

Induction period evaluated from time domain dielectric response of oil‐paper insulation (OPI) contains information related to heat dissipating property of oil. In the present paper, effect of aging sensitive oil properties on the value of induction period is investigated. Three types of dielectric liquids (pure mineral oil, synthetic ester, mixture of synthetic ester, and mineral oil) are considered for the present work. A neural network (NN) is used for modelling the non‐linear relationship between induction period and various oil properties. The trained network is subsequently used to study the influence of various oil properties on induction period. [ABSTRACT FROM AUTHOR]

To investigate the effect of aging on surface discharge of the pressboard on the shielding electrode at the end of bushing, a thermal aging preparation methods of different aging degrees of pressboard samples, surface defect model, and the associated hemisphere are designed and the step‐up method is used for subsequent experimental work. Finally, the partial discharges (PDs) under different degrees of aging are compared and combined with Fourier Transform Infrared spectra and electric field simulation. Results show that the pre‐discharge occurs mainly in the oil gap between the hemispherical electrode edge and the pressboard. The aging of the pressboard exerts no obvious effect on the discharge characteristics in the initial stage of PD; with the development of the discharge, the development of aging of pressboard leads to a higher electric field intensity acting over a greater area, the more intense the discharge, the faster the relative discharge increases and the larger its amplitude. This discharge will cause decomposition of the oil in the pores of the aging pressboard thus generating gas bubbles which will move as discharge develops. When the bubbles reach the surface of the pressboard, the local electric field intensity will increase and the discharge will become more intense. [ABSTRACT FROM AUTHOR]

This study investigated the inhibitory effects of adsorption treatment on the degradation of oil–paper insulation and corrosive sulphur in oil. A thermal ageing experiment at 130°C was conducted using five different adsorbents to adsorb some impurities in oil on the 15th day of a 30 day ageing test, the related characteristics of oil–paper insulation before and after the adsorption treatment were measured and analysed. Meanwhile, a thermal ageing experiment at 150°C was also conducted before using five different adsorbents to adsorb dibenzyl disulphide (DBDS) in oil, energy dispersive X‐ray was used to evaluate the degree of the corrosion of windings. The result indicates that adsorption treatment is an effective method to inhibit the degradation of oil–paper insulation. A molecular sieve, silica gel and activated alumina can effectively improve the performance of oil–paper insulation. By contrast, the antioxidant (2, 6‐di‐tert‐butyl‐p‐cresol) can be also adsorbed by adsorbents, which accelerate the ageing degradation of the insulating oil. On the other hand, the adsorbents can adsorb DBDS in oil, but cannot remove all DBDS. The effect achieved from silica gel is especially significant, which not only effectively improves the performance of oil–paper insulation but also adsorbs DBDS in oil. [ABSTRACT FROM AUTHOR]

This paper investigated the influence of 2, 6‐di‐tert‐butyl‐p‐cresol (DBPC) on the long‐term ageing characteristics of oil–paper insulation and the deposition and migration of copper sulphide induced by the reaction of copper and dibenzyl disulphide (DBDS) in oil‐immersed transformers. A thermal ageing experiment at 130°C were designed and conducted by adding different concentrations of DBPC to the naphthenic mineral oil and after the experiments a set of characteristic parameters were tested. The result indicates that the excessive concentration (≥0.6%) of DBPC will slightly increase the ageing of insulating oil and increase the carboxyl group in the mineral oil, affecting the reaction of DBDS and copper, and the insulating paper wrapped on the copper strip was also aged seriously accordingly. Meanwhile, the deposition of copper sulphide on the insulating paper is found to be slightly increased with the increase of the concentration of DBPC. When insulating oil contains DBPC and DBDS, due to migration of DBDS–Cu and DBPC–Cu in oil, the copper ions in the oil would be fluctuating at a certain period of time. Although the addition of a small concentration of DBPC can improve the antioxygenic property of the insulting oil to some extent, the transformers that contain excessive concentration of DBPC may be more harmful than beneficial. [ABSTRACT FROM AUTHOR]

Frequency domain spectroscopy (FDS) is being used to assess the insulation condition of oil–paper power transformers. However, it has to date only been implemented on de‐energised transformers, which requires the transformers to be shut down for an extended period and may cause significant costs. To solve this issue, a newly improved monitoring method based on the FDS principle is proposed to implement the dielectric measurement on energised transformers. Moreover, a chirp waveform excitation and its novel processing method are introduced. Compared with the conventional FDS results, dielectric results from the energised insulation system have higher tanδ values because of the increased losses. To further understand the insulation ageing process, the effects of the geometric capacitance are removed from the measured imaginary admittance of the insulation system to enhance the ageing signature. The resulting imaginary admittance is then shown to correlate well with the central time constant in return voltage measurements results. The proposed methods address the issues on techniques used on energised transformers and provide a clue for on‐line FDS diagnostic application. [ABSTRACT FROM AUTHOR]

Despite being a well‐known problem, bearing faults are still one of the major challenges that the industry face. The growing use of voltage source inverters imposed the alertness of possible bearing damage due to their high‐frequency signals. The aim of this paper is to investigate the effect of capacitive discharges on a rolling element bearing to obtain a series of faulty bearings with different deterioration levels. An ageing test bench is built to generate bearing roughness using Electric Discharge Machining. The purpose is to study the effect of operation conditions, such as frequency of drive, amplitude of shaft voltage, radial load level as well as rotational speed, on the capacitive discharge occurrence within the bearing. Having the desire to further understand this phenomenon, the influence of each parameter on the discharge activity and the discharge waveform is analysed. A worst‐case scenario is conducted and applied to a series of bearings. Finally, the bearing damage is examined, and a quantitative fault detection method is presented based on a microscopic inspection of the bearing's surface. [ABSTRACT FROM AUTHOR]

Power transformers are vital to delivering energy in power grids and they bear considerable maintenance costs annually. One of the major issues for power transformers is the ageing of the insulation paper used in windings that affects the life of transformers significantly. Utilising an appropriate procedure for loading of transformers can reduce the ageing rate of insulation and can improve the life expectancy. Therefore, it is crucial to obtain the values for the ageing rate which are optimum and to prevent transformer fleet from accelerated ageing. Although techniques are available to calculate the ageing rate and loss of life of a single transformer, utilities looking into the transformer fleet ageing need a better tool to improve the ageing rate of all transformers together. The main contribution of this study is to provide a method for the transformer fleet ageing optimisation rather than single unit ageing approach. This study proposes a novel approach utilising different optimisation techniques that are capable of representing different factors in order to obtain an optimum ageing rate for a fleet of transformers. The optimum ageing rate can provide a technical tool for asset managers, utility engineers and owners for better power transformer fleet management. [ABSTRACT FROM AUTHOR]

In this study, different types of antioxidants (AO) such as natural and synthetic AOs are mixed with mineral oil (MO) at various individual and grouping concentrations to enhance the life of transformers. Water content in oil, water content in paper, breakdown voltage, acidity, 2‐furaldehyde concentration, degree of polymerisation and tensile strength are the laboratory‐based ageing‐related performance characteristics considered in the proposed work to evaluate the degradation rate of MO samples. Multi‐criteria decision‐making methods such as analytic hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) are used to identify the sample concentration which gives maximum performance while considering all the characteristic performance of the MO samples precisely. Two different methods are employed to assess the performance characteristics of the MO samples. In first method, AHP is employed for both priority weight calculation and ranking of MO samples. In second method, AHP is used for weight calculation and TOPSIS is used for ranking. From the experimental results, it is found that, the MO sample S5 yields better performance when compared with other samples. Hence, it is suggested that MO sample S5 can be the best alternative for transformer oil. [ABSTRACT FROM AUTHOR]

Current research on human aging has largely been guided by the milestone paper "hallmarks of aging," which were first proposed in the seminal 2013 paper by Lopez‐Otin et al. Most studies have focused on one aging hallmark at a time, asking whether the underlying molecular perturbations are sufficient to drive the aging process and its associated phenotypes. More recently, researchers have begun to investigate whether aging phenotypes are driven by concurrent perturbations in molecular pathways linked to not one but to multiple hallmarks of aging and whether they present different patterns in organs and systems over time. Indeed, preliminary results suggest that more complex interactions between aging hallmarks must be considered and addressed, if we are to develop interventions that successfully promote healthy aging and/or delay aging‐associated dysfunction and diseases. Here, we summarize some of the latest work and views on the interplay between hallmarks of aging, with a specific focus on mitochondrial dysfunction. Indeed, this represents a significant example of the complex crosstalk between hallmarks of aging and of the effects that an intervention targeted to a specific hallmark may have on the others. A better knowledge of these interconnections, of their cause‐effect relationships, of their spatial and temporal sequence, will be very beneficial for the whole aging research field and for the identification of effective interventions in promoting healthy old age. [ABSTRACT FROM AUTHOR]

The leakage current characteristic monitoring of transmission line insulators is considered a worthy technique for insulator state prediction. In this paper, the harmonic analysis of leakage current signals has been performed to analyze the composite insulator condition. Experimental studies of asymmetrically aged, fully aged, and virgin insulators have been conducted. The effects of different aging types, pollution, and humidity on leakage current components, such as harmonics and the phase differences with the applied voltage, have been investigated. The analysis of the results shows that the effect of asymmetric aging on leakage current components is non‐linear, and this non‐linearity increases with the degree of pollution. Also, the type of insulator aging can be determined by the ratio of the third‐ and fifth‐order leakage current harmonics. For instance, the classification of insulators into virgin, asymmetrically aged, and fully aged can be determined by examining the corresponding value ranges of 0–0.5, 0.5–0.9, and > 0.9, respectively. Similarly, the phase difference values of < 15% and those > 15% indicate the clean and polluted operating conditions individually. [ABSTRACT FROM AUTHOR]

Background: The global population is ageing rapidly and there is a need for strategies to promote health and wellbeing among older adults. Nutrition knowledge is a key predictor of dietary intake; therefore, effective educational programmes are urgently required to rectify poor dietary patterns. Digital health technologies provide a viable option for delivering nutrition education that is cost‐effective and widely accessible. However, few technologies have been developed to meet the unique needs and preferences of older adults. Objective: The aim of this study was to explore technology use among older adults and qualitatively determine the content needs and design preferences for an online nutrition education resource tailored to older adult consumers in Australia. Methods: Twenty adult participants aged 55 years and older (95% female) participated in one of four 2‐h participatory design workshops. In each workshop, prompted discussion questions were used to explore participants' technology use and preferences and to explore content needs and design preferences for an online nutrition education resource specific to older adults. Results: All participants were regularly using a range of different devices (e.g., smartphones, tablets and computers) and reported being comfortable doing so. Participants wanted a website that provided general nutrition information, practical advice and recipes. To enhance engagement, they sought a personalised resource that could be adjusted to suit their needs, included up‐to‐date information and allowed for easy sharing with others by exporting information as a PDF. Conclusions: Participatory design methods generate new knowledge for designing and tailoring digital health technologies to be appropriate and useful for the target audience. Specifically, older adults seek an online resource that has large and simple fonts with clear categories, providing them with practical advice and general nutrition information that can be personalised to suit their own needs and health concerns, with the option to export and print information into a paper‐based format. Patient or Public Contribution: Older adults actively participated in the development and evaluation process to generate ideas about potential features, functionalities, uses and practicalities of an online nutrition education resource. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geographer is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The frequency domain dielectric response method has been one of the most effective approaches for condition assessment of an electrical insulation system. The low‐frequency part is more effective for diagnosing the moisture content and aging status of oil‐paper insulation. To facilitate the study of the low‐frequency dielectric spectrum of oil‐paper insulation, a model applicable to the low‐frequency dielectric response of insulation oil is proposed in this study, which is based on the ionic motion of insulation oil. The creation of charge carriers under field test conditions mainly derives from the dissociation of ionic pairs. During testing, ionic motion of insulation oil is jointly affected by thermal diffusion and the electric field; moreover, dissociation and recombination of negative and positive ions also occur. Therefore, the above factors were all considered in the modelling process. The applicability of the model is verified against measured results. For further interpreting the proposed model, the characteristics of the ionic concentration distribution, the relation between ionic distribution and dielectric properties, and the application of the proposed model are analysed. [ABSTRACT FROM AUTHOR]

In order to seek the optimal mass fraction for the modified pressboards to improve electric ageing resistance ability, the samples modified by nano-TiO2 with 1, 3, 5 and 7% mass fractions were made in the lab. The electrical ageing experiments were carried on these samples. The dielectric properties tests, partial discharge (PD) and DC breakdown were executed on the samples to analyse the electrical ageing performance of the cellulose pressboards modified by nano-TiO2. The interface charge accumulation and decay characteristics of the samples were also tested. The nano-TiO2 distributions and the surface morphology for the cellulose pressboards aged 0 and 40 h were observed by scanning electron microscope (SEM) to verify the modification effect, and the trap density characteristics of unmodified and modified samples were also described. The permittivity and the conductivity properties of the modified samples are more advantageous than the unmodified ones after electrical ageing. The electrical characteristics of the modified samples are better than the unmodified ones for different electrical ageing stages. The analysis of SEM images and trap distribution give a good verification to the improvement of the modified samples for different ageing stages. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geographer is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent progress in geroscience holds the promise of significantly slowing down or even reversing ageing and age‐related diseases, and thus increasing our healthspans. In this paper, I offer a novel argument in favour of developing such technology and making it unconditionally available to everyone. In particular, I argue that justice requires that each person be provided with sufficient opportunities to have a 'complete life', that many people currently lack such opportunities, and that we would substantially improve the status quo by giving them access to anti‐ageing technology. [ABSTRACT FROM AUTHOR]

Sarcopenia is a progressive and widespread skeletal muscle disease that is related to an increased possibility of adverse consequences such as falls, fractures, physical disabilities and death, and its risk increases with age. With the deepening of the understanding of sarcopenia, the disease has become a major clinical disease of the elderly and a key challenge of healthy ageing. However, the exact molecular mechanism of this disease is still unclear, and the selection of treatment strategies and the evaluation of its effect are not the same. Most importantly, the early symptoms of this disease are not obvious and are easy to ignore. In addition, the clinical manifestations of each patient are not exactly the same, which makes it difficult to effectively study the progression of sarcopenia. Therefore, it is necessary to develop and use animal models to understand the pathophysiology of sarcopenia and develop therapeutic strategies. This paper reviews the mouse models that can be used in the study of sarcopenia, including ageing models, genetically engineered models, hindlimb suspension models, chemical induction models, denervation models, and immobilization models; analyses their advantages and disadvantages and application scope; and finally summarizes the evaluation of sarcopenia in mouse models. [ABSTRACT FROM AUTHOR]

During normal operation, power transformer insulation always experiences a temperature gradient along radial direction with respect to core axis. Over time, this gradient creates non‐uniform ageing within cellulosic insulation. Recent development such as Modified Debye Model (MDM) is found to be capable of modelling such non‐uniformity. Owing to non‐uniform ageing, measured tan δ value only provides the average of dielectric loss associated with various regions within the insulation. Researchers have observed tan δ value to be quite high (due to conductive ageing by‐products) in heavily degraded areas such as regions closer to winding. Also, the rate of deterioration of various regions within the insulation cannot be assumed to be constant. In fact, rate of degradation for regions with comparatively high tan δ values are expected to be much higher. tan δ measurement fails to assess the individual condition of different regions. A technique, based on MDM, is introduced in the present work that can identify the change in ageing severity of various regions within a non‐uniformly aged insulation between two consecutive testing. The proposed method is first successfully tested on multiple series connected laboratory samples. Thereafter, the methodology is applied to data recorded from real life power transformer. [ABSTRACT FROM AUTHOR]

Background: Trans‐identifying individuals experience unique barriers and challenges in negotiating health‐care systems due to the cisnormative attitudes and practices which obstruct the receipt of trans‐inclusive care. To date, there has been little exploration of older trans consumers' experiences of contemporary health‐care services when seeking to transition medically in later life. Objectives: Qualitative findings are presented from a study of trans ageing and trans‐related health and social care needs in Wales, UK (2016‐18). The objectives are to (1) examine supportive and obstructive points of interaction with health‐care professionals, and (2) identify key learning messages for improving trans‐related health care from the perspectives of trans‐identifying adults in later life. Design: Trans‐identifying participants self‐selected to take part in two interviews—a life‐history interview and a semi‐structured interview. Interview data were analysed thematically using the framework method approach. Setting and participants: This paper focuses on the accounts of 19 participants (50‐74 years of age) who identified as trans and were seeking to transition medically in mid‐ to later life. Results: Findings indicate how older trans patients are positioned as reluctant educators for GPs in primary care settings and illustrate the transphobic practices and cisnormative assumptions encountered across health‐care interactions and systems that impede their journey of transitioning in later life. Discussion and conclusions: Messages from this study speak to the importance of improving professionals' knowledge of gender identity diversity across the life course and making changes at a systemic level in redressing cisnormative assumptions and systems that reinforce inequities on the basis of gender identity. [ABSTRACT FROM AUTHOR]

Rooftop photovoltaics (RPVs) have an impact on the ageing failure rate and reliability of transformers. The advantages and disadvantages of different penetrations of rooftop photovoltaic on the reliability of the transformers are studied. For the first time, the adverse effects of high penetration of RPVs on the transformer failure and power system reliability are examined. Regarding the growing interest in the widespread use of renewable energies on account of global warming, studying the negative effects of DG units presence is so important to predict the future of power system conditions. Monte Carlo simulation is used for the probabilistic nature of clearness index and reliability evaluation. Well‐being criteria that show the different operation modes of the power system is used to identify the at‐risk, marginal and healthy mode of the power system in the presence of different penetrations of rooftop photovoltaic. The results show that the maximum penetration of rooftop photovoltaic for improving the reliability of the power system is 5 kW per house in the feeder of Isin in Bandar Abbas, in Iran. [ABSTRACT FROM AUTHOR]

Due to the limitations imposed by urban power grid outages for maintenance, on‐line harmonic current detection technology for distribution network cables is expected to become an effective supplement to traditional offline diagnostic methods, enhancing the real‐time diagnosis of distribution network cable insulation conditions. This study established a 10 kV distribution network cable test platform and prepared typical defective cables subjected to moisture and long‐term thermal aging. Using COMSOL finite element electromagnetic simulation, the magnetic flux evolution laws of the cable insulation under typical defects were obtained. Experimental tests provided the harmonic current characteristics and statistical features of cables with typical defects. Based on these data, a method for analysing the degradation degree of distribution network cables was constructed using least absolute shrinkage and selection operator (LASSO) regression analysis. Furthermore, a defect‐type identification method based on cluster analysis was proposed. Results indicate that the odd harmonics and the 4th harmonic of the distribution network cable's harmonic current are closely related to the cable's degradation state. A model integrating principal component analysis (PCA) data dimensionality reduction and expectation‐maximization clustering analysis achieved a recognition accuracy of up to 75.64% in distinguishing between moisture‐affected and normal cable states. The proposed on‐line detection and evaluation methods can effectively identify high‐risk cables with latent defects. [ABSTRACT FROM AUTHOR]

Skeletal muscle (SM) acts as a secretory organ, capable of releasing myokines and extracellular vesicles (SM‐EVs) that impact myogenesis and homeostasis. While age‐related changes have been previously reported in murine SM‐EVs, no study has comprehensively profiled SM‐EV in human models. To this end, we provide the first comprehensive comparison of SM‐EVs from young and old human primary skeletal muscle cells (HPMCs) to map changes associated with SM ageing. HPMCs, isolated from young (24 ± 1.7 years old) and older (69 ± 2.6 years old) participants, were immunomagnetically sorted based on the presence of the myogenic marker CD56 (N‐CAM) and cultured as pure (100% CD56+) or mixed populations (MP: 90% CD56+). SM‐EVs were isolated using an optimised protocol combining ultrafiltration and size exclusion chromatography (UF + SEC) and their biological content was extensively characterised using Raman spectroscopy (RS) and liquid chromatography mass spectrometry (LC‐MS). Minimal variations in basic EV parameters (particle number, size, protein markers) were observed between young and old populations. However, biochemical fingerprinting by RS highlighted increased protein (amide I), lipid (phospholipids and phosphatidylcholine) and hypoxanthine signatures for older SM‐EVs. Through LC‐MS, we identified 84 shared proteins with functions principally related to cell homeostasis, muscle maintenance and transcriptional regulation. Significantly, SM‐EVs from older participants were comparatively enriched in proteins involved in oxidative stress and DNA/RNA mutagenesis, such as E3 ubiquitin‐protein ligase TTC3 (TTC3), little elongation complex subunit 1 (ICE1) and Acetyl‐CoA carboxylase 1 (ACACA). These data suggest SM‐EVs could provide an alternative pathway for homeostasis and detoxification during SM ageing. [ABSTRACT FROM AUTHOR]

Brain atrophy and cortical thinning are typically observed in people with Alzheimer's disease (AD) and, to a lesser extent, in those with mild cognitive impairment. In asymptomatic middle‐aged apolipoprotein ε4 (ΑPOE4) carriers, who are at higher risk of future AD, study reports are discordant with limited evidence of brain structural differences between carriers and non‐carriers of the ε4 allele. Alternative imaging markers with higher sensitivity at the presymptomatic stage, ideally quantified using typically acquired structural MRI scans, would thus be of great benefit for the detection of early disease, disease monitoring and subject stratification. In the present cross‐sectional study, we investigated textural properties of T1‐weighted 3T MRI scans in relation to APOE4 genotype, age and sex. We pooled together data from the PREVENT‐Dementia and ALFA studies focused on midlife healthy populations with dementia risk factors (analysable cohort: 1585 participants; mean age 56.2 ± 7.4 years). Voxel‐based and texture (examined features: contrast, entropy, energy, homogeneity) based morphometry was used to identify areas of volumetric and textural differences between APOE4 carriers and non‐carriers. Textural maps were generated and were subsequently harmonised using voxel‐wise COMBAT. For all analyses, APOE4, sex, age and years of education were used as model predictors. Interactions between APOE4 and age were further examined. There were no group differences in regional brain volume or texture based on APOE4 carriership or when age × APOE4 interactions were examined. Older people tended to have a less homogeneous textural profile in grey and white matter and a more homogeneous profile in the ventricles. A more heterogeneous textural profile was observed for females in areas such as the ventricles, frontal and parietal lobes and for males in the brainstem, cerebellum, precuneus and cingulate. Overall, we have shown the absence of volumetric and textural differences between APOE4 carriers and non‐carriers at midlife and have established associations of textural features with ageing and sex. [ABSTRACT FROM AUTHOR]

This research explores the role of microRNA in senescence of human endothelial progenitor cells (EPCs) induced by replication. Hsa‐miR‐134‐5p was found up‐regulated in senescent EPCs where overexpression improved angiogenic activity. Hsa‐miR‐134‐5p, which targeted transforming growth factor β‐activated kinase 1‐binding protein 1 (TAB1) gene, down‐regulated TAB1 protein, and inhibited phosphorylation of p38 mitogen‐activated protein kinase (p38) in hsa‐miR‐134‐5p‐overexpressed senescent EPCs. Treatment with siRNA specific to TAB1 (TAB1si) down‐regulated TAB1 protein and subsequently inhibited p38 activation in senescent EPCs. Treatment with TAB1si and p38 inhibitor, respectively, showed angiogenic improvement. In parallel, transforming growth factor Beta 1 (TGF‐β1) was down‐regulated in hsa‐miR‐134‐5p‐overexpressed senescent EPCs and addition of TGF‐β1 suppressed the angiogenic improvement. Analysis of peripheral blood mononuclear cells (PBMCs) disclosed expression levels of hsa‐miR‐134‐5p altered in adult life, reaching a peak before 65 years, and then falling in advanced age. Calculation of the Framingham risk score showed the score inversely correlates with the hsa‐miR‐134‐5p expression level. In summary, hsa‐miR‐134‐5p is involved in the regulation of senescence‐related change of angiogenic activity via TAB1‐p38 signalling and via TGF‐β1 reduction. Hsa‐miR‐134‐5p has a potential cellular rejuvenation effect in human senescent EPCs. Detection of human PBMC‐derived hsa‐miR‐134‐5p predicts cardiovascular risk. [ABSTRACT FROM AUTHOR]

Background: The Concord Health and Ageing in Men Project (CHAMP) is a cohort study of the health of a representative sample of older Australian men. The aim of this paper is to describe the oral health behaviours and dental service use of CHAMP participants and explore associations between oral health behaviours with and general health status.Method: Information collected related to socio-demographics, general health, oral health service-use and oral health behaviours. Key general health conditions were ascertained from the health questionnaire and included physical capacity and cognitive status.Results: Fifty-seven percent of the men reported visiting a dental provider at least once or more a year and 56.7% did so for a "dental check-up". Of those with some natural teeth, 59.3% claimed to brush their teeth at least twice or more a day. Most men (96%) used a standard fluoride toothpaste. Few participants used dental floss, tooth picks or mouth-rinses to supplement oral hygiene. Cognitive status and self-rated general health were associated with dental visiting patterns and toothbrushing behaviour.Conclusions: Most older men in CHAMP perform favourable oral health behaviours. Smoking behaviour is associated with less favourable dental visiting patterns, and cognitive status with toothbrushing behaviour. [ABSTRACT FROM AUTHOR]

The mechanisms that underpin the evolution of ageing and life histories remain elusive. Oxidative stress, which results in accumulated cellular damages, is one of the mechanisms suggested to play a role.In this paper, we set out to test the "oxidative stress theory of ageing" and the "oxidative stress hypothesis of life histories" using a comprehensive phylogenetic comparison based on an unprecedented dataset of oxidative physiology in 88 free‐living bird species.We show for the first time that bird species with longer lifespan have higher non‐enzymatic antioxidant capacity and suffer less oxidative damage to their lipids. We also found that bird species featuring a faster pace‐of‐life either have lower non‐enzymatic antioxidant capacity or are exposed to higher levels of oxidative damage, while adult annual mortality does not relate to oxidative state.These results reinforce the role of oxidative stress in the evolution of lifespan and also corroborate the role of oxidative state in the evolution of life histories among free‐living birds. A plain language summary is available for this article. Plain Language Summary [ABSTRACT FROM AUTHOR]

Power device reliability is a multidisciplinary domain. It requires design and integration of sensors, implementation of signal processing algorithms that allow processing the different data provided by the different sensors in order to predict by statistical means the device failure occurrence and consequently anticipate the power device replacement. Currently, for device ageing studies in a laboratory, electrical measurements of device parameters are often used as an indicator of device ageing. Furthermore, smart metal‐oxide semi‐conductor technology integrates more and more sensors that permit to measure quantities such as on‐state resistance or junction temperature of the device. In power vertical diffused metal oxide semiconductor (VDMOS) assemblies, it would be interesting to make use of the VDMOS electrical parameters deviations in order to monitor the ageing state of the power assembly. To that end, we carry‐out in this paper a study mainly based upon electro‐thermo‐mechanical simulations in order to identify the power VDMOS electrical parameters that could be monitored in order to access to the mechanical state of the power assembly and therefore anticipate the assembly failure. The power VDMOS Ron as well as zero temperature coefficient (ZTC) point are of interest because they are sensitive to mechanical stress. Consequently, in this paper, a procedure to minimise temperature impact on the Ron of the VDMOS transistor such that one could use the Ron as mechanical state indicator is shown. Another solution that makes use of a specific operating point of VDMOS (ZTC) which is temperature independent is also studied by simulations and experiment. [ABSTRACT FROM AUTHOR]

In recent years, abnormal heating of composite insulators has become a serious problem, especially in the coastal areas of southern China. In this paper, an improved multi‐stress aging test for composite insulators was proposed based on the environment of the coastal areas in southern China, and 5000 h aging test was carried out. The test results showed that the wet flash‐over voltage decreased linearly, while the hydrophobicity of the shed showed a nonlinear aging characteristics, whose change rate increased gradually. The multi‐stress aging condition had little influence on shed hardness for the change of the shed hardness remained within 1%. The aged composite insulator showed significant temperature rise and the temperature rise concentrated on the high voltage end at high humidity, while it showed little temperature rise at low humidity. The dielectric loss of silicone rubber after moisture absorption was tested. It could effectively reflect the moisture absorption characteristics and the dielectric properties of silicone rubber after moisture absorption, and was closely related to the wet flash‐over voltage and temperature rise of the composite insulator. The dielectric loss of silicone rubber after moisture absorption could be used as a new method to evaluate the operating state of composite insulators. [ABSTRACT FROM AUTHOR]

Abstract: The elderly are often considered a vulnerable group in public and academic bioethical debates and regulations. In this paper, we examine and challenge this assumption and its ethical implications. We begin by systematically delineating the different concepts of vulnerability commonly used in bioethics, before then examining whether these concepts can be applied to old age. We argue that old age should not, in and of itself, be used as a marker of vulnerability, since ageing is a process that can develop in a variety of different ways and is not always associated with particular experiences of vulnerability. We, therefore, turn to more fundamental phenomenological considerations in order to reconstruct from a first person perspective the intricate interconnections between the experiences of ageing and vulnerability. According to this account, ageing and old age are phenomena in which the basic anthropological vulnerability of human beings can manifest itself in an increased likelihood of harm and exploitation. Thus, we plead for a combined model of vulnerability that helps to avoid problems related to the current concepts of vulnerability. We conclude first that old age as such is not a sufficient criterion for being categorized as vulnerable in applied ethics, and second that reflections on ageing can help to develop a better understanding of the central role of vulnerability in human existence and in applied ethics. [ABSTRACT FROM AUTHOR]

During the ageing process, TNF‐α can promote the expansion of myeloid‐derived suppressor cells (MDSCs). However, it remains unclear which receptor(s) of TNF‐α are involved in and how they modulate this process. Here, we report that TNFR2 hyperexpression induced by either TNF‐α or IL‐6, two proinflammatory factors of senescence‐associated secretory phenotype (SASP), causes cellular apolarity and differentiation inhibition in aged MDSCs. Ex vivo overexpression of TNFR2 in young MDSCs inhibited their polarity and differentiation, whereas in vivo depletion of Tnfr2 in aged MDSCs promotes their differentiation. Consequently, the age‐dependent increase of TNFR2 versus unaltered TNFR1 expression in aged MDSCs significantly shifts the balance of TNF‐α signaling toward the TNFR2–JNK axis, which accounts for JNK‐induced impairment of cell polarity and differentiation failure of aged MDSCs. Consistently, inhibiting JNK attenuates apolarity and partially restores the differentiation capacity of aged MDSCs, suggesting that upregulated TNFR2/JNK signaling is a key factor limiting MDSC differentiation during organismal ageing. Therefore, abnormal hyperexpression of TNFR2 represents a general mechanism by which extrinsic SASP signals disrupt intrinsic cell polarity behavior, thereby arresting mature differentiation of MDSCs with ageing, suggesting that TNFR2 could be a potential therapeutic target for intervention of ageing through rejuvenation of aged MDSCs. [ABSTRACT FROM AUTHOR]

In our previous study, intranuclear cardiac troponin I (cTnI) may function as a co‐factor of Yin Yang 1(YY1). Here, we aimed to explore the role of intranuclear cTnI in ageing hearts. Nuclear translocation of cTnI was demonstrated using Western blot and immunofluorescence. The potential nuclear localization sequences (NLSs) of cTnI were predicted by a web server and then verified in 293T cells by putative NLS‐eGFP‐GST and NLS‐mutant transfection. The ratio of Nuclear cTnI/ Total cTnI (Nu/T) decreased significantly in ageing hearts, accompanied with ATG5‐decline‐related impaired cardiac autophagy. RNA sequencing was performed in cTnI knockout hearts. The differential expressed genes (DEGs) were analysed by overlapping with YY1 ChIP‐sequencing data. cTnI gain and loss experiments in vitro determined those filtered DEGs' expression levels. A strong correlation was found between expression patterns cTnI and FOS. Using ChIP‐q‐PCR, we demonstrated that specific binding DNA sequences of cTnI were enriched in the FOS promoter −299 to −157 region. It was further verified that pcDNA3.1 (−)‐cTnI could increase the promoter activity of FOS by using luciferase report assay. At last, we found that FOS can regulate the ATG5 (autophagy‐related gene 5) gene by using a luciferase report assay. Taken together, our results indicate that decreased intranuclear cTnI in ageing hearts may cause impaired cardiac autophagy through the FOS/ATG5 pathway. [ABSTRACT FROM AUTHOR]

Background: Photo‐ageing is a form of skin ageing which affects the entire face. A photo‐aged skin has a diverse variety of wrinkles and dyspigmentation all over the face. Here, we discuss photo‐ageing on the Chinese skin evaluated using a photo‐numeric scale developed and validated on Caucasian skin (i.e., Caucasian scale) and evaluated using a photo‐numeric scale developed and validated on Korean skin (i.e., Korean scale). The Korean scale can be subdivided into two scales that separately address the wrinkling and dyspigmentation constituents of photo‐ageing. Aim: As there are currently no photo‐ageing scales for Chinese skin, the main objective of this study is to adapt existing photo‐ageing photo‐numeric scales for use on ethnic Chinese skin. Method: Three trained assessors studied facial photo‐ageing on 1,081 ethnic Chinese young adults from the Singapore/Malaysia Cross‐sectional Genetics Epidemiology Study (SMCGES) cohort. Results: All assessors are highly internally consistent (Weighted Kappa (κw) values≥0.952). We found that the Caucasian scale and Korean scale give nearly synonymous results for the wrinkling constituent of photo‐ageing (R2 = 0.9386). The two scales are strongly concordant (Spearman's Rank Correlation (ρ) value: 0.62 ± 0.06, p = 1.31×10−84). A weak‐to‐moderate inter‐scalar level of agreement (Cohen's Kappa (κ) values: 0.38 ± 0.05, p = 8.87×10−53) persists and is statistically significant after accounting for agreements due to chance. When tested on ethnic Chinese skin, both scales detect photo‐ageing consistently (Area under curve [AUC] values: 0.76‐0.84). Additionally, the Korean scale for the dyspigmentation constituent of photo‐ageing is concordant with both the Caucasian scale (R2 = 0.7888) and the Korean scale for the wrinkling constituent of photo‐ageing (R2 = 0.7734). Conclusion: Our results show that the Caucasian scale is suitable for capturing photo‐ageing on Chinese skin, especially wrinkle variations. The Korean dyspigmentation scale supplements the Caucasian scale to capture dyspigmentation patterns on Chinese skin that may be absent on Caucasian skin. Currently, photo‐ageing scales for Chinese skin are absent. When developed, these photo‐ageing scales must be properly validated for their ability to capture photo‐ageing of the entire face. [ABSTRACT FROM AUTHOR]

Background: Older people with intellectual disabilities and their families report a lack of support for planning for parental death and transitions in care. This article aims to demonstrate the process of co‐designing resources to support older people with intellectual disabilities and their families to plan for the future. Methods: Following interviews and focus groups with older people with intellectual disabilities and their families, we used an adapted experience‐based co‐design process to develop planning ahead resources. This included a 'trigger film' summarising findings from the earlier interview study, 12 co‐design workshops and a user feedback phase. Results: The co‐design group developed a set of 102 'Planning Ahead Cards' to help families to talk about the future and prepare for meetings with social care professionals. The group made decisions about the content, format and design of resources, and how co‐design workshops would run. The user feedback phase led to changes to the cards, and families and stakeholder groups suggested that they would be useful for planning ahead. Conclusion: The Planning Ahead Cards may facilitate planning for parental death and transitions in care for older people with intellectual disabilities and their families. The co‐design approach was key to ensuring that the resources were useful and accessible for families. Patient or Public Contribution: People with intellectual disabilities and their families contributed to the design of the resources through the co‐design workshops and feedback phase. The research team includes a research assistant with intellectual disabilities who co‐facilitated co‐design workshops and co‐authored this article. [ABSTRACT FROM AUTHOR]

Lightning striking on power system may lead to severe accident and huge losses, which is the reason why line arresters are needed. During operation, the electrical field concentration in line arrester may lead to ablation and accelerated aging of insulation materials, and furthermore, cause mal-operation. A type of line arresters with internal series air gap (IGLA) is chosen by this study, which is distinguished from the previously used metallic oxide arrester, with better characteristic on anti-flashover when icing, but with worse characteristic on anti-flashover when polluted. This paper aims at studying the probable variation of power-frequency electric field of this new kind of IGLA under polluted and icing situation, and making further analysis on the reason why the electric field strength change like this. [ABSTRACT FROM AUTHOR]

Ageing results in lower exercise tolerance, manifested as decreased critical power (CP). We examined whether the age‐related decrease in CP occurs independently of changes in muscle mass and whether it is related to impaired vascular function. Ten older (63.1 ± 2.5 years) and 10 younger (24.4 ± 4.0 years) physically active volunteers participated. Physical activity was measured with accelerometry. Leg muscle mass was quantified with dual X‐ray absorptiometry. The CP and maximum power during a graded exercise test (PGXT) of single‐leg knee‐extension exercise were determined over the course of four visits. During a fifth visit, vascular function of the leg was assessed with passive leg movement (PLM) hyperaemia and leg blood flow and vascular conductance during knee‐extension exercise at 10 W, 20 W, slightly below CP (90% CP) and PGXT. Despite not differing in leg lean mass (P = 0.901) and physical activity (e.g., steps per day, P = 0.735), older subjects had ∼30% lower mass‐specific CP (old = 3.20 ± 0.94 W kg−1 vs. young = 4.60 ± 0.87 W kg−1; P < 0.001). The PLM‐induced hyperaemia and leg blood flow and/or conductance were blunted in the old at 20 W, 90% CP and PGXT (P < 0.05). When normalized for leg muscle mass, CP was strongly correlated with PLM‐induced hyperaemia (R2 = 0.52; P < 0.001) and vascular conductance during knee‐extension exercise at 20 W (R2 = 0.34; P = 0.014) and 90% CP (R2 = 0.39; P = 0.004). In conclusion, the age‐related decline in CP is not only an issue of muscle quantity, but also of impaired muscle quality that corresponds to impaired vascular function. What is the central question of this study?Does the age‐related decrease in critical power occur independently of changes in muscle mass and is it related to impaired vascular function?What is the main finding and its importance?The age‐related reduction in exercise tolerance, assessed by critical power, occurs independently of loss of muscle mass and is related to vascular function and exercise blood flow. Blood flow during exercise slightly below critical power reaches very high steady‐state levels that do not differ significantly from the maximum blood flow achieved during exercise above critical power. [ABSTRACT FROM AUTHOR]

Falls have a global impact, affecting people worldwide, with a notably high occurrence among the elderly. This study employs machine learning techniques to analyze falls and simulate Activities of Daily Living (ADL). The objective is to predict human falls by leveraging signals from accelerometers and gyroscopes as wearable sensors. By deriving statistical features such as mean, standard deviation, and range the authors successfully trained and assessed six machine learning models allowing them to compare solutions based on both wrist and waist data. The combination of these characteristics and sensors resulted in the Random Forest waist model achieving the most favorable metrics, with an accuracy rate of 97.22% in a 5‐s window. [ABSTRACT FROM AUTHOR]

Allergic diseases often occur early in life and persist throughout life. This life‐course perspective should be considered in allergen immunotherapy. In particular it is essential to understand whether this al treatment may be used in old age adults. The current paper was developed by a working group of AIRWAYS integrated care pathways for airways diseases, the model of chronic respiratory diseases of the European Innovation Partnership on active and healthy ageing (DG CONNECT and DG Santé). It considered (1) the political background, (2) the rationale for allergen immunotherapy across the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing. [ABSTRACT FROM AUTHOR]

It is known that marine cable is responsible for the transmission of electric energy and electrical signals of the ship. In order to predict the residual life of cable under discontinuous operation, a non-destructive online life prediction model is established based on retention rate of hardness (RRH). This study takes the marine ethylene propylene rubber (EPR) cable as the research object. Using time temperature superposition principle, the optimal time temperature shift factor is calculated using particle swarm optimisation and steepest descent method. After that the main curve was fitted exponentially to acquire the relationship between RRH and ageing time. Compared with the existing model, the results indicate that the proposed model has higher prediction accuracy. On this basis, the residual life prediction model based on RRH of marine EPR under discontinuous operation is presented by adding time parameters. The effectiveness of the method is verified by simulation. Thus, it provides theoretical guidance for solving the problem of marine cable replacement time. [ABSTRACT FROM AUTHOR]

The proposed study compares the electrical, thermal and mechanical performances of thermally aged cellulose pressboard material impregnated in mineral oil, synthetic ester fluid and mixed oil. The electrical insulation characteristics of oil‐impregnated pressboard (OIP) are studied by means of surface discharge inception voltage (SDIV) using an ultra‐high frequency technique and surface potential measurement analysis. It indicates that OIP aged in mineral oil has higher surface potential due to higher charge trap density compared to that of the mixed oil and synthetic ester fluid. Mechanical and thermal characteristics of the aged OIP are studied by means of tensile strength measurement and thermo‐gravimetric analysis, respectively. The change in the chemical composition of OIP is studied by means of laser‐induced breakdown spectroscopy, which indicates lower plasma temperature with mineral oil‐based OIP indicating higher degradation state. To further understand the microscopic structure of the thermally aged OIP in different oils, scanning electron microscopy and X‐ray diffraction studies have been performed. The pressboard thermally aged in synthetic ester fluid and the mixed oil has better electrical, thermal and mechanical properties as compared with the pressboard aged in mineral oil. [ABSTRACT FROM AUTHOR]

The life loss of batteries caused by the daily operation implies a reduction in capital value, which is essential for the economic performance of storage‐containing systems. Most of current studies rarely considered it or simplified it to be proportional of throughput electricity, due to its multi‐factor dependence and complexity to be incorporated into dispatch models. This study presents a dynamic loss evaluation model for batteries that considers the cumulative effect of state of charge (SOC) changes. First, based on the results of battery aging test, the loss coefficient subject to SOC is derived. The general formulation of analytical battery life loss is further presented by integrating the damage effect during the change in SOC. Finally, by means of self‐optimal piecewise linearisation, the resultant life loss term is embedded in the online wind‐storage integrated scheduling. Case studies demonstrate the desirable computational complexity of the proposed evaluation method and the adaptability in general economic dispatch. [ABSTRACT FROM AUTHOR]

Carrying out the insulation condition measurement and analysis is important for the safe operation of the submarine cable. In this study, the high‐voltage frequency dielectric response is used to identify the ageing state of the AC 500 kV cross‐linked polyethylene (XLPE) submarine cable. The complex capacitance and tanδ in the low‐frequency area for the new, thermal ageing, electro‐thermal ageing cable all increase with the testing voltage increased from 200 to 2000 V. It is founded that the dielectric response at high voltage is more likely to detect the ageing differences. Based on the carbonyl index and the dielectric loss of the XLPE specimens at different position of the insulation layer, the non‐uniform ageing phenomenon of the cable insulation is presented for the thermal ageing and electro‐thermal ageing cable. The loss quantity parameter and its changing behaviour with testing voltage based on the frequency dielectric response could be used to identify the ageing state. The comparison of the modified Cole–Cole model parameter under 200 and 2000 V also indicates that the higher voltage dielectric response is helpful to identify the ageing differences. [ABSTRACT FROM AUTHOR]