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Transformers Magazine Vol. 4 Issue 4
Dear Readers, A big part of the materials that we publish in the magazine is aimed at shedding light on the evolution of the transformer technology and market from different points of view. However, this evolution might be much more drastic than what we imagine if we don’t look at the complete environment for transformers. According to a new report Energy Transition Outlook 2017 by… 
Tap-changer DGA: Uncovering an enigma Part 2: Basic procedures In Part 1 of this article, the general field of tap-changer DGA has been outlined. In Part 2, I will dig somewhat deeper and show some basic procedures which enable the user to define limit values for gas concentrations and gas increasing rates, or which allow a distinction between “good” and “bad”, based on the qualitative… 
Changes bring opportunity Fast-paced changes in requirements for transformers are fuelling a comprehensive evolution affecting the standards, technology, business, market, and in the end, the people. This was stated in the article Support in technology and market development published in Transformers Magazine, Volume 4, Issue 3, which looked more closely at the evolution of the environment around transformers – the technology and the market. In… 
Market evolution I have been working in the power product industry for the last 21 years. I started with high-voltage breakers in 1996, where I spent twelve years, and the last nine years I have been working with transformers in different positions, first as a manager for tap-changers and then for components, covering both tap-changers and bushings. These positions included a lot of worldwide travel… 
Towards condition-based maintenance Power transformers are becoming older and older and it is not uncommon to see a service life of more than 50 years. Operators also have new challenges to face, such as higher and fluctuating transformer loads from renewable energies, higher probabilities of equipment failure and a lack of information about the condition of transformers. While transformer assessments used to be based primarily… 
Generator step-up transformers Background The development of global power generating capacity since the first "oil shock" in the early 1970s has evolved dramatically and has had a fundamental impact on the production of generator step-up (GSU) transformers. With relatively cheap oil prices in the order of $10 per barrel, this and coal was the fuel of choice for most developed country electricity utility companies. The… 
Huaming Vacuum Tap-Changer CV2 Introduction With thousands of installed base products and more than 10 years of field experience, CV2 vacuum tap-changer is claimed to be the most reliable and economic solution for intended voltage regulation up to 132 kV for transmission and distribution transformers. Product for heaviest application Compared to diverter switch, selector switch design features compact size and has a more economical cost.… 
The home of core cutting and stacking technology L.A.E. – Lughese Attrezzature per l’Elettromeccanica S.r.l. has been recognized for intensive research and development in the fields of core cutting and stacking technology. The company continues in the same direction, with most recent milestones including the extensions of the portfolio of core cutting lines with a new machine TO 45, and the portfolio of stacking robots… 
Improved transformer temperature monitoring Abstract This article discusses transformer temperature monitoring where a strategy of reduction in maintenance costs and outages, by replacing older ancillary technology with modern IEDs, can offer a reduction in maintenance costs, while providing an increase in availability and reliability. Winding temperature indicators are critical devices on a transformer as they not only control the cooling system, but also provide the… 
Power transformers are among the most expensive equipment in any energy supply network. Given the high investment costs, it pays to calculate precisely before making a purchase decision. The largest German distribution network operator performed a comparison between two different options: a transformer with conventional outdoor connections, or with pluggable Connex connection technology by Pfisterer. The calculation reveals that while price is an important factor,… 
Abstract Power transformers are vital pieces of equipment in the power grid. However, the measures taken to safeguard these critical transmission nodes from high-powered ballistics are often insufficient. This article presents the threat that ballistics attacks pose to transformers and the consequences such attacks may have on the broader power grid. Physical protection measures available to transmission system operators are then discussed, including a tank-mounted… 
Introduction The Isolated Phase Bus Duct (IPBD) is the main conduit for power distribution in a power generation facility. With current carried between the generator and a step-up transformer solely via the IPBD system, it is the undisputable critical core of any power generation operation. The need for proactive maintenance cannot be overstated in order to mitigate the risk of repairs, downtime, or catastrophic equipment… 
Transformer energisation after network blackout Abstract According to ENTSO-E Network policy 5, responsibility for system restoration after a blackout is on the shoulders of Transmission System Operators (TSOs). They are advised to have a firm plan in place for regular testing of system restoration functionality. Part of the network restoration includes energising transformers to supply various underlying grids. However, transformer energisation after a blackout is… 
A dry-type transformer (DDT) is a safe, low maintenance and environmental-friendly solution suitable for indoor and outdoor applications where not only safe and dependable power are important. It is also compacter in size than a liquid-filled transformer, making it especially suited for hard-to-access areas or those with limited space, such as wind turbines, off-shore platforms, indoor und underground substations, industrial plants and even high-rise buildings.… 
Abstract Due to constraints in the Irish transmission system, the Irish Transmission System Operator called for increased capacity in the network to cater for increased renewable generation by adding a 500 MVA, 400 kV transformer and a new 400 kV GIS substation on the Atlantic west coast. Due to the network configuration, the insulation level of Ireland’s 400 kV system is rated at 550 kV,… 
Winding resistance testing is a very revealing electrical diagnostic test for the routine screening of power transformers to determine their “state of health”. In fact, it’s an essential test when dissolved gas analysis indicates overheating in the oil or of the paper, and no condition assessment is complete without it. Moreover, if you were to ask experienced substation maintenance engineers for their thoughts about which… 
Introduction Finnish nuclear power company Teollisuuden Voima Oyj (TVO) implemented Vaisala’s online hydrogen, moisture and temperature monitor to constantly follow the condition of their transformers. The continuous monitoring gives information on the transformer oil 24/7, helping to plan maintenance actions. Reliability for credibility TVO has almost 40 years of experience in the safe and reliable production of reasonably priced electricity. The net output of its… 
Abstract This article explores the critical importance of the proper selection of copper, one of the key raw materials used in the making of continuously transposed conductors for extra high voltage power transformer windings. Windings are one of the most vulnerable components of a power transformer in terms of withstanding various types of electrical disturbances that lead to transformer failure. They have to satisfy complex… 
Introduction Using the Oweld oxy-hydrogen gas generators, designed and manufactured by Oxyweld, transforms your brazing line into a modern and cutting-edge place that increases the prestige of your company. The technology that is already approved by the main transformer manufacturers enhances efficiency and productivity of the process. Company overwiev Oxyweld is a leading Italian manufacturer of oxyhydrogen gas generators for brazing. With its Oweld brand… 
AbstractThis article demonstrates how the inclusion of partial discharge as a measurement parameter ensures a more reliable diagnosis of insulation condition in transformer bushings. Comparative diagnostic tests showed that the partial discharge measurements best enabled the detection of bushing defects, which the other methods were not able to detect alone. The tests were performed in the lab on oil-impregnated paper (110 kV – with induced defects)… 
UK steelworks have gone through a turbulent time in recent years, but there is now some stability as the UK and global marketplaces once again appears more attractive. Although investment is being made, money has to be spent wisely, and transformer refurbishment, with a focus on the health of the insulation system (oil and paper), has become a priority for Tata Steel Port Talbot’s engineers… 
