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Anton M. Holter (1831-1921) was a pioneer Helena, Montana, lumberman and founder of the A.M. Holter Hardware Company. Papers (1831-1921) include correspondence, and organizational and financial records relating to mining, agriculture, lumber, real estate, and oil interests of three generations of the family, headed successively by Anton M. Holter, Norman B. Holter, and Norman J. "Jeff" Holter. Many of the enterprises were in partnership with Samuel T. Hauser. Interests include the A.M. Holter Hardware Company; Holter Realty; Holter Research Foundation; Judith Farms; Montana Flour Mills; and the Helena and Frisco, Helena and Victor, and Maginnis mining companies, This collection is arranged into several major subgroups. The first group is for the Holter Family and allied families. The second major group is for the Holter Family Enterprises. The remainder of the collection consists of records of numerous companies grouped together in categories, including Mining subgroups, Lumber and Timber subgroups, Agriculture subgroups, Real Estate and Investment subgroups, Mercantile subgroups, Oil subgroups, Utility and Transportation subgroups, and Miscellaneous subgroups. Within each subgroup the basic arrangement is alphabetical by the name of the company., The Holter Family Subgroup of the collection contains correspondence and other materials relating to individual family members. Within this subgroup is a series of family correspondence, which contains letters written between various Holters. The correspondence between Anton M. Holter and his sons, primarily Norman, Edwin, and Aubrey, and the correspondence between the three brothers, provides invaluable information concerning the many facets of the family's business activities and investments. Therefore, researchers are encouraged to read this family correspondence regardless of the topic of interest., The greatest value of the collection is its completeness and its century-long time span coverage. The materials serve to provide invaluable information on the Holter family; the family companies, particularly the A.M. Holter Hardware Company; the growth and development of Helena and vicinity; and the lumber, ranching, and mining industries in the Northwest. The only weakness in the collection is the lack of any meaningful materials documenting the political activities of the period. The name index accompanying this inventory is not meant to be a complete listing of all materials in the collection, but attempts to provide some guidance in relating companies and individuals. No effort was made to include the three main Holters, Anton, Norman, or Jeff, in the index. (Manuscript Collection 80).

Colorimetric gas detectors have been widely applied in many fields such as environmental sciences, industrial hygiene, process control, forensic science and indoor air quality monitoring. They have a history of about 100 years and include devices such as gas detector tubes and paper-based gas detectors. The sensitivity and selectivity of the colorimetric gas detector are relatively high compared to other types of gas detectors such as semiconductor, catalytic combustion and electrochemical gas detectors. Detection of gas concentration can be performed by the naked eye in some colorimetric gas detectors. These methods do not require an electrical power source and are simple, so they are suitable for field operations. This review introduces the history and provides a general overview of the development in the research of colorimetric gas detectors. Recently, the sensitivity and selectivity of colorimetric gas detectors have improved. New materials such as enzymes or particles with a large surface area have been utilized to improve selectivity and sensitivity. Moreover, new gas detectors without toxic materials have been developed to reduce the environmental load. At present, there is a rapid development of IoT sensors in many industrial fields, which might extend the applications of colorimetric gas detectors in the near future.

The power transformer is one of the most important equipments that has a critical role in good electrical power delivery. Ageing of paper insulation inside the transformer is irreversible and hugely related to the operation of power transformer. This study involved inspection data from in-service and out-of-service 150 kV power transformers provided by the Indonesian electric company. The degree of polymerization (DP) of the cellulose paper insulation and furanic compound in the insulating oil can be used to estimate the transformer's lifetime. In this study, the correlation between HI decreasing rate (HI dec_rate ) and the loading factor of 115 transformers historical data was observed. The DP of the transformer paper was predicted (DP pred ) using the ANFIS model using the dielectric characteristics and dissolved gases as input. The results show that the correlation between the DP pred decreasing rate (DP dec_rate ) and the loading factor is more significant than that between the HI dec_rate and the loading factor

In remote areas, such as India, Africa and Southeast Asia, typically not connected to the natural gas distribution network, tissue paper production is currently carried out using a Yankee cylinder and two hot air hoods heated with saturated steam produced in conventional boilers. In this way the drying air is heated at medium temperature, around 160-180 °C, with consequent low levels of dried paper production. In this context, the present study intends to evaluate the technical and economic feasibility of using a wood biomass fixed bed downdraft gasification plant for the production of syngas to be used as fuel in gas hoods, in order to reach high drying temperatures (around 500 °C), comparable with those of the current modern hoods powered with natural gas. Using previously developed calculation codes, an evaluation of energy performance of the paper drying system and of the gasification plant has been performed. The present study also evaluates the possibility of applying a CHP plant, powered by biomass, for the production of steam and electric, this last obtained adopting a steam turbine, thus covering all the electrical and thermal needs of the paper mill. Results show that, for a paper mill with a production of about 80 t/day of paper, two gasification reactors with a thermal output of about 1.95 MWt, and a consumption of dry biomass of 0.86 t/h, are required. For the steam system, the net electric power needed to meet the needs of the paper mill is about 3100 kW with a consumption of 4.72 t/h of moist biomass and a net efficiency of 23.9 %.

The use of vegetable oil (natural ester) in electrical devices like power transformers is increasing due to their high biodegradability and better safety. The lifespan of power trans- formers is mainly defined by cellulose insulation condition, which usually works together with dielectric oil as electrical insulation and also as mechanical winding protector and compactor. That is why the aim and results of this research shows us not only the dielectric parameters evolution, but also the relationship between the mechanical factors and the moisture content of thermal accelerated ageing processes, with commercial vegetable oil, of Kraft paper and Diamond Dotted Paper (DDP). These are two of the most common insulating materials in electric power transformers. In addition, the new tests have been done by a different method of paper ageing analysis. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement Nº 823969 - BIOTRAFO.

The subsector of pulp and paper presented in 2013 an electric power consumption of 9.3% of electricity consumption in the industrial sector in Brazil. It experienced a significant growth of production in the last 20 years, exceeding 160%, and their consumption of electricity increased by 130%, reaching the level of 19,594GWh. Due to its characteristics, with a known structure and production processes, and its importance in the country's industrial sector, this subsector was selected for study in this paper, to evaluate the behavior of its long-term annual electricity demand, at the horizon of 20 years ahead, in energy efficiency scenarios through bottom-up approach. This approach is data intensive and requires data with good quality; it consists of a hierarchical structure that enables to check how specific actions can affect the results at each level and its effect on higher levels.

This work presents the development and optimization of a very low cost, miniaturized and lightweight aluminum/silver oxide (Al/AgO) primary battery. The system is implemented on painted paper supported electrodes and it is activated using a small amount of water. The anode contains an improved composite based on aluminum powder. The cathode is made using an electrical conductive silver epoxy ink. The device displays a paper-based core comprising the electrodes and the paper matrix separator, modified with a highly concentrated dry potassium hydroxide salt, inside a flexible laminated plastic structure that provides sturdiness to the system making it safe and portable for the user. The battery turns on by applying 80 μl of water and as a result the system produces a maximum capacity of 0.5 mAh when 1.6 mA cm−2 are applied. The generated electrical power of two batteries in series is then used to power a LED during approximately one hour. Although there is room for improvement, these results allow envisaging the battery as a real commercial portable power source and allow planning potential uses of this energy to power microelectronics demanding low power consumption, such as sensors or wearable electronics.

An original partial discharge generated in oil insulation identification methodology based on simultaneously conducted measurements using electrical method, ultra high frequency method and acoustic emission method is presented in the paper. Three different partial discharge model sources as well as measuring instruments commonly applied for partial discharge detection in electrical power transformers are yielded within a laboratory research. Total of 45 scenarios, including proposed spark gap configurations, selected supply voltage levels and UHF frequencies are analyzed during measurements series. Furthermore, form among total of 93 descriptors assigned for every applied partial discharge model source configuration there are 24 proposed as potentially useful for partial discharge identification applications with their 95% confidence bounds. Attempt of discriminative descriptors selection for partial discharge source analysis in on-site transformer applications as well as a proposal of unique descriptors according to every selected spark gap configuration that could be potentially useful for partial discharge identification purposes are the main purpose of the presented paper. The proposed methodology verification on a real life transformer with particular consideration of the selected descriptors potential utility in the fields of partial discharge detection and identification in electrical power industry applications confirmed a proposed methodology usefulness.

Strongly electric fish use gradients of ions within their bodies to generate stunning external electrical discharges; the most powerful of these organisms, the Atlantic torpedo ray, can produce pulses of over 1 kW from its electric organs. Despite extensive study of this phenomenon in nature, the development of artificial power generation schemes based on ion gradients for portable, wearable, or implantable human use has remained out of reach. Previously, an artificial electric organ inspired by the electric eel demonstrated that electricity generated from ion gradients within stacked hydrogels can exceed 100 V. The current of this power source, however, was too low to power standard electronics. Here, an artificial electric organ inspired by the unique morphologies of torpedo rays for maximal current output is introduced. This power source uses a hybrid material of hydrogel-infused paper to create, organize, and reconfigure stacks of thin, arbitrarily large gel films in series and in parallel. The resulting increase in electrical power by almost two orders of magnitude compared to the original eel-inspired design makes it possible to power electronic devices and establishes that biology's mechanism of generating significant electrical power can now be realized from benign and soft materials in a portable size.

This work demonstrates a stand-alone power source that integrates a paper-based hydrogen fuel cell with a customized chemical heater that produces hydrogen in-situ upon the addition of a liquid. The presented approach operates by capillary action and takes advantage of the hydrogen released as a by-product of an exothermic reaction used in point-of-care diagnostics. The paper-based fuel cell produces a maximum power of 25.8 mW (103.2 mW cm−2), which is suitable for powering a diversity of electrical devices such as commercially available digital pregnancy tests and glucometers. While device shape and dimensions can be customized, here it is shown that the fuel cell can be designed in a compact form factor and footprint comparable to a lateral flow test while providing a remarkable power output. This approach holds great promise for powering portable diagnostics, as the generated electric power could enable device functionalities required for advanced assays, such as device timing, actuation, and signal quantification. Part of the same liquid sample that is to be analyzed (urine, saliva, water, etc) could be used to trigger the hydrogen generation and start the fuel cell operation., J.P. Esquivel acknowledges support from Marie Curie International Outgoing Fellowship (APPOCS - GA.328144) within the 7th European Community Framework Programme. J. Buser and P. Yager were supported by a grant from DARPA DSO/BTO--HR0011-11-2-0007, awarded to Yager at the University of Washington. P. Yager was supported in part by funds from the Department of Bioengineering at the University of Washington. S. Rojas acknowledges financial support from project ENE2013-42322R. N. Sabaté would like to thank financial support received from ERC Consolidator Grant (SUPERCELL - GA.648518).

Electric power equipment has complex construction. Therefore, it is very important to have enough information about the state of equipment. High voltage transformers play a very important role in the electric power system. One of the most important parts of electric power equipment is the insulation system. Insulation system must be in a good condition for reliable and safe operation of electrical devices. Insulation system of electrical equipment is exposed to various factors which could have negative influence on its condition. Oil impregnated insulation paper is one of the oldest insulation systems used in electrical power equipment. Mineral oils have been used for decades as transformer fluids because of their excellent dielectric properties and availability. However, performance of mineral oil starts to be limited due to environmental consideration. The aim of this paper is to simulate a real insulation system of transformer and to show the influence of accelerated thermal ageing on the insulation system. Properties such as relative permittivity, dissipation factor and the breakdown voltage will be described and analysed.

Using mathematical programming with activity-based costing (ABC) and based on the theory of constraints (TOC), this study proposed a green production model for the traditional paper industry to achieve the purpose of energy saving and carbon emission reduction. The mathematical programming model presented in this paper considers (1) revenue of main products and byproducts, (2) unit-level, batch-level, and product-level activity costs in ABC, (3) labor cost with overtime available, (4) machine cost with capacity expansion, (5) saved electric power and steam costs by using the coal as the main fuel in conjunction with Refuse Derived Fuel (RDF). This model also considers the constraint of the quantity of carbon equivalent of various gases that are allowed to be emitted from the mill paper-making process to conform to the environmental protection policy. A numerical example is used to demonstrate how to apply the model presented in this paper. In addition, sensitivity analysis on the key parameters of the model are used to provide further insights for this research.

Moisture has a significant effect on the dielectric strength of paper insulation used in the transformer. Variation of moisture in paper insulation accelerates the ageing process of cellulose, degrading the insulating properties of the paper. As a result, the failure of the transformer occurs to leading catastrophic losses in the whole electrical power system. This paper describes a method to determine the moisture content of insulation paper at laboratory environment based on the change of the refractive index of insulation paper due to the variation of moisture in it. Influence of temperature on the cellulose paper material has been considered in the experiment for the proper estimation of moisture in the paper insulation.

Transformer is a vital equipment in electrical power system that can degrade faster or slower than its designated life. In order to recognize the vulnerability of a transformer in a fleet, Health Index is commonly used. Conventional Health Index approach require all the data to be available in order to obtain accurate condition of a transformer. However, frequently incomplete data such as furfural is often faced by asset manager. This paper demonstrated the use of seven models to substitute unavailable furfural. Health Indices of 200 transformers with complete data were calculated, and compared to the alternative models. Multiple imputation approaches to predict paper condition of transformer using Multiple Linear Regression (MLR) and ANFIS (Adaptive Neuro-Fuzzy Inference System) had better agreement than other approaches shown by higher coefficient correlation with complete Health Index, as much as 0.959 and 0.960 respectively.

Harvesting energy from environmental moisture is a promising technique for sustainable electric power resource. Herein, a new scalable fabrication method for flexible moisture-electric energy transformation device by dispersing or direct printing carbon dots (CDs) on paper is reported. A facile strategy for self-establishing ionic gradient on both sides of the device by constructing an asymmetric structure (the side of device is encapsulated) is proposed, which avoids prior processing of the materials for building asymmetric functional groups. The carboxyl groups on CDs near the open side of the device ionize more protons than that near the closed side, resulting in a potential drop across the device due to the concentration difference of the released protons on the two sides. The device can produce a sustainable voltage of −40 mV for over 100 min at a fixed humidity value. In addition, the device responds to direct touching of a finger or human exhalation, thus indicating its great potential for applications in electronic skins and humidity sensors.

Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary.

Variable-speed operation of wind turbines (WTs) achieved through electronic converters can decouple wind generator dynamics from power systems. Besides, the wide rotor operation range makes it possible for the WT to tap the potential of kinetic energy (KE) in the rotating mass. This study provides an overview of utilising KE from WTs for grid connections. The availability of KE in WTs is acquired by the rotor speed alternation, both in static and dynamic processes. For the static state, the rotors of WTs operate at a pre-defined power curve which leaves the generation margin for KE release; while for the dynamic process, the KE is passively changed by the imbalance between mechanical and electrical power. Some emerging technologies in frequency regulation and low-voltage ride through capability with the participation of KE stored in WTs are investigated. The applications of KE in terms of wind smoothing are summarised as well. Finally, this literature review also discusses some potential future applications of KE management.

This paper discusses the progress made on Côte d'Ivoire’s National Development Plan (PND) 2012–15. In the area of planning, the 2012–13 PND served to move planning to the forefront of public action. In addition, the National Bureau of Population has been set up to better address the problems of population and development. In the area of justice and human rights, the policy guidance paper has been prepared and is now being implemented. In the area of civil protection, the actions carried out have centered on strengthening the institutional and legal framework for preventing and managing risks and disasters and building up the operational capabilities of bodies in charge of civil protection.

Power transformers play vital role in electrical power system, that makes it crucial to monitor its current condition. Measurements of oil-paper insulation health index through parameters like Furfural (2FAL) and Degree of Polymerization are keys to assess life of power transformer, despite the fact that those measurements are not included in routine test. This paper presents the use of Artificial Intelligence to do condition assessment of oil-paper insulation of power transformer through its dissolved gases and dielectric characteristics. As much as 182 in-service transformers are observed and were used as training set of the ANFIS and FIS-ID3 model, while 69 other transformers were used as testing dataset. Acidity, Interfacial tension, CO, and CO 2 are potential to become input parameters of the health index. The result shows that FIS-ID3 have some advantages over ANFIS that is worthily noted for the next development.

Second only to safety, the most critical aspect related to electrical power on an offshore platform is reliability. Reliability can be broken down into three subcategories; availability, stability, and quality. Availability mainly pertains to the status of the primary equipment. Stability is achieved by having an effective Power Management System (PMS) to regulate voltage and frequency even during abnormal conditions (e.g. the sudden trip of a generator). Quality is a diverse topic, but the fundamental point is that the power delivered must be suitable for the loads and continuously monitored. By optimizing each of these subcategories, the reliability of the electrical power is maximized. This paper will cover technical details related to design and testing of an offshore platform PMS which uses many of the benefits of the IEC 61850 Standard, including Generic Object Oriented Substation Event (GOOSE) messaging between Intelligent Electronic Devices (IEDs) and controllers to achieve fast power-based load shedding and load inhibition in a real application.

The paper presents new diagnostic method applied to assess aging degree for paper-oil insulation used in professional electrical power device, primarily including medium and high power transformers. The described method is based on modified diagnostics using the recovery voltage effect occurring in dielectrics (RVM – Recovery Voltage Methods). Modification of the RVM method applied so far, which is now used only to assess moistening degree for paper-oil insulation in power transformers, consists in a new parametric analysis of recovery voltage time characteristics. Simulation and experimental tests carried out in laboratory conditions for adequately prepared insulation samples have proven that the time-constant of recovery voltage decay (τR_MIN) is the most susceptible parameter as regards quantitative change in the function of aging of the examined insulation. This conclusion is also confirmed by statistical studies, in which a multi-parameter variance analysis method has been applied. An original equivalent circuit diagram of the insulation has been used to simulate aging degree of paper-oil insulation samples in numerical tests. The diagram is based on the Cole-Cole type dielectric response model.

At the present time, reliability and stability of electric power have been very important when it comes to electrical systems in any plants, especially in terms of distribution. Phoenix Pulp & Paper PCL (PPPC) in Khon Kaen, Thailand, is currently generating electric power about 90% of its current needed by themselves and buys the rest from Provincial Electricity Authority (PEA). Nonetheless, the protection system should be installed to protect the electrical bus when electrical generating process trips or breakdown. Otherwise, it would cause the shutdown of electrical system and lose all manufacturing. To protect electrical system, PPPC therefore has to use load shedding system for cutting the connection of the machines from the system within few minutes. Power flow of electric power from 115 kV PEA to 11 kV via 2 transformers of 115 kV/11 kV and PPPC's 3 generators are studied in this research by setting the real electric power (P), reactive electric power (Q), current (I) and voltage (V) in the protection relay of load shedding system of 11 kV switchboards. In addition, motor control panel, simulated by SKM Power Tools program, is investigated in this research work. The simulation results: P, Q, I and V will be divided into 4 cases: the trips from TG-PUC, TG2, TG3 (in-house generation) and the one from PEA. In the case that there is a trip from PEA electrical distribution, P, only generated from the first three generators in house, will be insufficient to cover the plant's electric need and require around 6,512 kW more. As a result, the machines would have to be stopped running. However, if there is a trip from its in-house generation (TG-PUC, TG2 and TG3) instead, some P can be directly received from PEA. Thus, the load shedding scheme is important to protect the blackout system from electrical system's trip in distribution.

Transformer is a crucial component of the electrical power system. Usually, using differential protection Transformers are being protected. But whenever a transformer is energized, sometime malfunctioning may take place in the differential protection due to inrush current. Some methods are used to minimize the fault. Those methods are like per-phase method, cross-blocking method, Percent average blocking method and harmonic sharing method. Then fuzzy logic scheme has been used to separate the internal fault from magnetizing inrush current. After that, a differential protection has been used which was based on wavelet packet transform. Then Mathematical morphology based inrush blocking scheme has been used. In this paper comparison are made between per-phase method, cross-blocking method, percentage average blocking method, harmonic sharing method, fuzzy logic, wavelet packet transform based technique and Then Mathematical morphology based inrush blocking scheme.

The article concerns the presence of water in insulating systems consisting of cellulose materials impregnated with different electro-insulting liquids. This is a particularly important issue regarding power transformers with their strategic importance for an electrical power system. Water is a serious threat and can be the reason of a dangerous breakdown. Thus there is a need to have insulating system diagnostics in terms of water content. The article discusses the issue of water solubility in different electro-insulating liquids. The author determined the water saturation limits for these liquids. Moreover, the author determined water sorption isotherms for cellulose materials of different aging degree. On the basis of the obtained results, equilibrium curves were constructed for some selected kinds of insulation. The research results presented here allow to improve the reliability of determining moisture in cellulose insulation of various polymerization degree on the basis of water content measurement in an electro-insulating liquid.

As measured standardly by levelized cost of energy (LCOE), onshore wind and utility scale solar PV (photovoltaic) have been rapidly declining in cost and are now reported to be the cheapest ways of generating electric power. While this is indisputably a welcome development, the fact that renewables in general --- wind and solar in particular --- are variable and available only intermittently makes LCOE a quite incomplete, perhaps even misleading, measure of value because it neglects the system cost of accommodating renewables for the sake of meeting demand and keeping the grid in balance. The additional cost of building and employing peaker plants (mainly fueled by natural gas), which serve as backup and reserve and hence are often idle, has led many observers to pessimistic conclusions about the economic viability of very high levels of penetration by renewable sources of energy. This paper fully acknowledges the problem. We present an ensemble of several ideas that plausibly may be useful for mitigating the intermittency problem accompanying high levels of penetration of renewable power generation, particularly solar PV (photovoltaic). The ensemble, presented as a proposed setup or institution, includes provision for dispatchable solar PV (and by extension wind power) as well as provision for a market for what we call variable supply electric power. This is described in the paper and contrasted with existing services, which may be described as guaranteed supply. Further, we confront our proposed setup with three years of insolation data for Philadelphia, PA. This leads to a number of quantified measures of variability that should be useful for system design and management. This is an exploratory paper, aiming at an initial vetting of these ideas. Very much remains to be done to investigate them fully.

Failure of high voltage bushing leading to partial or complete destruction of power transformer has been considered as severe event in the electrical power system. Apart from power distribution it has led to human tragedy in a number of sites. Transformer industry is concerned with such problems and hence several committees have discussed the phenomena. Amongst other reasons attributed to it, the failure of draw lead causing complete failure of bushing and insulation breakdown in paper insulation between aluminum foil and the core has been major cause at power plant. The present paper aims at formulating an electrical equivalent network comprising inductances, capacitances and resistances representing the bushing and draw lead. The voltage distribution in the annular region of draw lead and aluminum pipe supporting core of HV bushing is calculated using Electro Magnetic Transient Programme [EMTP] programmed for standard and fast impulse voltage surge. The analysis shows that higher stress leads to the failure of draw lead and paper insulation of the core. Photographs of failed bushing along with initiating spots are given in the paper.

This IET Special Issue, features papers presented at VPPC 2014 and focuses on state-of-the-art research and development, as well as identifying future trends in the modelling, design, control, and optimisation of energy storage components and electric power sub-systems for advanced vehicles. These include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs), as well as electrified and advanced tractions and propulsions for trains, subways, ships, and aeroplanes. After a new independent peer review process, five top level extended papers were selected for this Special Issue.

Continuity of an electrical power supply to continuous processes is vital for overall success in an industrial setting. It is, therefore, critically important to accurately evaluate the degree to which the transformer insulation has been exposed to high temperatures and the degree of service aging which has occurred, even at normal temperatures. Concentration of carbon oxides dissolved in the oil is one marker commonly used, and concentration of furans dissolved in the oil is another. Sometimes, an apparent anomaly may develop in which the concentration of carbon oxides indicates a substantial long-term overheating, while at the same time the concentration of furans indicates that there has been a little aging of the solid insulation. Actual instances are analyzed and a logical explanation is developed. Guidelines are presented which address the development of this confusing situation and allow for logical conclusions as to the actual condition of the insulation system.