By Roman Targosz / Published on Thu, 2006-11-09 23:37
Application notes, reports, webcasts, presentations and minute lectures on high efficiency distribution transformers.
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By Bruno De Wachter / Published on Sat, 2009-11-07 06:05
What are the decision factors in replacing an operating distribution transformer with a new one
Usually, distribution transformers are only replaced after failing.
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By Isabelle Heriakian / Published on Thu, 2009-10-29 16:09
This guide presents a methodology based on standard PN-IEC 60354 to check overloading capacity of transformers. Main changes versus standard PN-71/E-81000 are discussed and step by step examples are given. An essential advantage of the recommended methods of verification of overloading capacity of transformers is that the size and cooling modes of transformers are considered.
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By Stefan Fassbinder / Published on Mon, 2009-08-31 08:33
Why do we need transformers? The answer is simple: impedance. If power losses in electricity distribution networks are to be kept within reasonable limits, then large amounts of electric power have to be transmitted across long distances at the highest feasible voltage. In absolute terms, the higher the trans-mission voltage, the smaller the current and hence the smaller the (resistive) power losses in the transmission cables. But increasing the transmission voltage also reduces a given power loss in relative terms.
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By HDK / Published on Wed, 2009-05-27 08:03
Ferroresonance is a phenomenon usually initiated by transients in power networks resulting from, for example, switching operations or ground faults. Non linear behavior of the core of an inductive voltage transformer results in magnetic saturation. Long-lasting ferroresonant states are dangerous to equipment due to prolonged overvoltage and large overcurrents in HV windings. In the present article, numerical simulations of the ferroresonance phenomenon in a HV inductive VT are presented.
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By Steve Aubertin / Published on Mon, 2009-04-27 08:25
Traditionally published reports have provided sales value data (historic and forecast) for various types of transformers, international trade values and regional market share data of the major suppliers. For most of the four decades transformer prices have been depressed and the relationship between sales value and sales volume has remained fairly constant and market value information was sufficient for most international marketing purposes.
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High Efficiency Distribution Transformers
By Hans De Keulenaer / Published on Wed, 2009-04-01 15:07
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By Walter Hulshorst / Published on Sun, 2009-02-01 10:39
Often windturbines in the range between 300 kVA up to 3000 kVA are connected to the MV grid by a distribution transformer. Very often it is easy to measure the electricity on the LV side of the transformer, which is connected to the windturbine. Since this is not the actual point of connection with the grid, it is needed to make an estimation of the energy losses due to the transformer.
As can seen from the figure above the measured electricity at the location of the meter equals to Ewind, while the actual delivered energy to the grid equals Edelivered. The difference between them are the losses caused by the transformer (strictly the cables should also be included). To calculate the electricity delivered it is necessary to make an estimation of the losses of the transformer.
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By jan.desmet@howest.be / Published on Wed, 2008-12-03 14:14
This Application Note discusses the effects of harmonic currents on power transformers. The main consequence is an increase in losses, mainly in the windings. Higher losses mean that more heat is generated in the transformer so that the operating temperature increases, leading to deterioration of the insulation and a potential reduction in lifetime. As a result, it is necessary to reduce the maximum power load on the transformer, a practice referred to as de-rating, or to take extra care in the design of the transformer to reduce these losses.
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By Hans De Keulenaer / Published on Thu, 2008-11-27 20:28
Michal Kaczmarek, Artur Szczêsny
Conductive disturbances in the power network may affect in abnormal operation of the electric energy loads and contemporary protection circuits connected to the voltage transformer. In certain condition voltage transformers may also become a source of the conductive disturbances which may affect the power quality.
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By Hans De Keulenaer / Published on Wed, 2008-11-26 20:25
Ali Kazemi, Schweitzer Engineering Laboratories, Inc.
Casper Labuschagne, Schweitzer Engineering Laboratories, Inc.
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By Angelo Baggini / Published on Wed, 2008-10-22 09:00
Year: 2006
Policy Status: In force
The Office of Energy Efficiency of Natural Resources Canada (NRCan) is proposed in October 2005 to amend Canada's Energy Efficiency Regulations to improve the energy efficiency of dry type transformers.
Dry-type transformers were added to Canada's Energy Efficiency Regulations on 23 April 2003 with an effective date of 1 January 2005. As a result of commentary received from transformer manufacturers, and analysis conducted by the department, NRCan is proposing to revise the definition of dry-type transformers as per the following:
- The tap range exemption will be eliminated. Elimination of the tap range exemption is based on the possibility of lower-cost exempt designs competing unfairly with efficient designs
- Drive (isolation) transformers with a single output winding will be included in the regulations, provided the low-voltage line current is 1500 A or less. This closes a loophole whereby a drive transformer could be bought by a distributor and sold as a regular transformer
- Non-ventilated transformers will be exempt from the regulations. This clarifies that non-ventilated transformers are not the same as sealed transformers, and should also be exempt
- Furnace transformers will be exempt from the regulations. Previously, furnace transformers were exempt by implication, but it was not explicitly stated in the regulations
- Previously, only transformers with a secondary voltage of 600 V or less were included in the regulations. Now, transformers will be included regardless of their secondary voltage. This eliminates a loophole that inadvertently exempted 3750-7500 kVA transformers
- Transformers having a low-voltage line current larger that 4000 A will be exempt from the regulations.
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By Hans De Keulenaer / Published on Thu, 2008-06-05 13:26
The SEEDT project, a cooperation between energy agencies, institutes, electrical utilities, transformer manufacturers and academic institutes, presents its new selection guide for energy efficient distribution transformers (EEDT).
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By Stefan Fassbinder / Published on Wed, 2008-06-04 17:52
Transformer tower in a rural area with only MV still overhead - LV (3-phase TN-C) has been undergrounded as a refurbishment as becomes evident from the remnants of the connections and fixtures
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By Stefan Fassbinder / Published on Wed, 2008-06-04 17:51
Transformer station (tower) in an older suburbian environment - MV underground - LV still partially overhead
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By Fernando Nuno / Published on Tue, 2008-06-03 15:29
By Miguel Oliva
This presentation provides a global view of recent applications in transformers, such as flow management in phase shifting transformers, the use of vegetable oil in high voltage applications, the implementation of ultra-low noise transformers and the intelligent monitoring of transformers.
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By Angelo Baggini / Published on Wed, 2008-03-26 17:08
The new EN 50464-1 Standard on three-phase oil-immersed distribution transformers 50 Hz, covering transformers up to 36 kV with power from 50 kVA to 2 500 kVA intended for indoor or outdoor continuous service introduced some remarkable new prescriptions on losses and efficiency according to a specific request by the European Commission.
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By Angelo Baggini / Published on Tue, 2008-03-25 13:28
A publication by IEC, summarising the international standards work carried out by IEC technical committees and emphasising future directions in the field of efficiency in energy distribution and transmission, contains a reference to the Leonardo ENERGY community on page 14:
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