Ten “Factor Ten” solutions [E-BOOK]

Amorphous distribution transformers

Technology

The reduction in Joule losses during the transport of electricity from power station production to users necessitates the use of high voltage and low amperage. Distribution electricity for domestic users, on the other hand, requires low voltage. Distribution transformers (DT) reduce the voltage of the electricity between the transport and the distribution. Two losses occur in DT: no-load losses, simply due to the fact that the DT is on the electric grid, and load losses, a function of the electric load.

Enhancements

Amorphous transformers use amorphous steel, instead of grain oriented steel. This change allows a significant decrease of losses in DT, resulting in energy savings. They are currently used in the USA and in India but not in the European Union. This situation exists because amorphous transformers are produced for voltages other than that used in Europe. Transformers are a local market, and amorphous DTs are therefore not produced in the EU. Furthermore, electric utilities prefer technologies they have already tested to those, which however promising they may be, are unfamiliar.

Future

The future of efficient and very efficient DT lies partly in a three step change: firstly, choosing the most efficient transformers from existing models (22 TWh savings have been estimated for the European Union), secondly, opting for amorphous transformers, and thirdly, switching to new technologies not yet industrially developed (as supra-conductive transformers).

Distribution transformers, new and old (Photo AERE)

Comments

Jan Leander's picture

There are a few factors regarding Amorphous transformers that always seems to be overlooked. Yes the technology is there however let's look at some other issues.

Today the annual consumption of electrical steel is in the range of 1.8-2 million ton of grain oriented steel while the production capacity of amorphous metal is roughly 60 000 ton. An amorphous transformer has approximately 50% larger core due to saturation limitations and larger stacking factor. So let's make it easy for us and say the annual production capacity of amorphous steel is equivalent to 40 000 ton of grain oriented steel. Then the maximum width of amorphous metal is 250 mm so it can not be used for power transformers. Let us say that the usage is 1/3 for power and 2/3 for distribution transformer. This would give a usage of 1.2 million ton of grain oriented steel for distribution transformer against a capacity today of 40 000 ton grain oriented steel equivalent. Roughly 3%!

Bigger core also result in more copper being used and more insulation materials like paper and oil. I understand why copper producers support amorphous steel as they then will sell more copper.

Todays manufacturing technologies in Europe is based on stacked core designs. Amorphous steel is 1/10 of the thickness of grain oriented steel and hard as tool steel. This makes it near to impossible to use in stacked designs. The reason it is used in US and Japan is that the technologies used there are wound core designs. The cores are not manufactured inhouse but at the steel suppliers facilities. These two basic designs are so far apart that European manufacturing equipment could not be used.
The day amorphous transformers could replace todays technologies on a larger scale we will already have super conducting technology. Then we will also not need transformers.

Keith Jenkins's picture

Stefan,Roman,
I work for a GO producer , so I can't pretend to be totally objective but I have to say I agree with Jan ( who I see actually works for a Transformer manufactuer ! ) From a "green" perspective it would be great if the world could have all new transformers with significantly reduced losses , but where will all this amorphous material come from? if you're right and that the market will make it happen Hitachi would be planning to increase it's production capacity ten- twenty fold not less than twice.(or we'd see a hugh rush of new manufacturers ) But in fact what we're seeing at the moment is a rise in demand for GO.
Have you guys any knowledge of flat stacked amorphous transformers ( power core came and went) ? again unless things change radically and transformer manufacturers move entirely to wound cores there will always be a practical limit to the size of transformers that can be built with amorphous material.
It would be good for you guys to get the views of Transformer manufacturers to add some balance to your comments/reports at the moment I feel you're not quite reflecting the realities of what's practical.

How did the workshop on Transformers go , will you be making the presentations available ?

Anonymous's picture

www.zhixindianqi.com.cn/en/ci3.aspx

www.metglas.jp/eng/f-amorphous.html

I hope this amorphous production chart will help

chanchal Jindal's picture

I an associated with a company manufacturing GO transformers. personally I have tried to be neutral in my openion.

In Indian distribution transformer market, amorphous metal Transformers(AMT) is hotly debated issue.

Of cousre no one can deny the fact the AMT are energy efficient in no load losses even as compared to best CRGO grades available in the market even the likes of ZDKH grade. But it is alway found that the copper losses component never gets due importance in this comparison usually the price differentail if used to reduce load losses can give far better results as one watt saved has same relevance irrespective from iron losses or copper losses.

To cite an example for 25KVA 11/0.433 KV transformer, Under BEE 4 star norms in India, the recommended total losses are 190 W at 50% loading and 635 W at 100% loading.
Now from designer's perspective, at 50% load both AMT and GO will have same efficiency however at 100% loading the losses of GO transformer will be approximately 520W and of that of AMT will be close to 635W.

The issue intended to be highlighted is that the ultimate objective should be the most efficient transformer for a given price. Other factors worth consideration are ease of availability, ease of repair, another important factor particularly relevant in case of develpoing countries is extant of overloading the transformers can be subjected to during its operational life.

Subject to above AMT could be used efficiently where there is skewed power demand with long idle periods. However where the transformer is the be subjected to loading conditions close to 100%, despite all developmets it's still no match to its conventional counterpart.

MOreover it is to been seen that apart from honeywell Hitachi, how many major producers start producing amorphous ribbons.

Stefan Fassbinder's picture

Dear Jan,

the lack of production capacity is a very poor argument to bring forward against any new technology. It could always be applied against everything. We might just as well turn the tables and say that superconductors have no chance at all because the worldwide production capacity is way too small compared to the world's conductor market. The capacity will grow as demand grows – no sooner than that.

The interest of the copper industry is evident and no secret, although the amorphous metal producers say that recent progress has brought the saturation up to 1.5T or even more, so the difference is dwindling away. But still, the copper people support this technology because they feel obliged to global energy efficiency improvements in general.

The unavailability of big cores is also a very poor argument against building the small ones. Most of the losses occur in small transformers. A bulk supply point or generator transformer has only some 0.02% of core losses, a distribution transformer has 10 times as much. But on the other hand the distribution transformer is too small and the absolute loss is too low to undergo the effort of cooling.

The superconducting transformer is a fairy tale. It will never come, unless someone invents a superconductor that works at room temperature. With an efficiency of 99.75% at full load and 99.80% at half load, there is too little left to save up because the cooling still needs to be fully sustained, be it at full load, part load, no load or during a shorter interruption of the transformer’s operation. Distribution transformers, on the other hand, are too small and the absolute loss is too low to undergo the effort of cooling.

Also note that superconductors can save the copper losses only, not the core losses. Rather, when you use common magnetic steel, its specific resistance will drop and yield a substantial increase in eddy current losses at lower temperatures. So you should cool the winding only and leave the core warm, but still the core will inevitably heat up the adjacent windings and add to the need of cooling.

Although it could have been calculated in advance, Siemens tried it out and built a prototype, but alas, there was no saving at all.

And now please tell me why we don’t need transformers any more when we use superconductors. The latest news is that a 50kV superconducting transmission cable has been devised. I don’t have any appliances for 50kV in my home, and I also don’t want any.

You had better forwarded the argument that a superconducting transformer does not burn so very well as the one filled with tons of oil which went on fire at Krümmel nuclear power plant. This at least would have been true (also see www.ivsupra.de), whenever leaving the question open how relevant this feature is.

Roman Targosz's picture

Amorphous cores which are 150% of typical GOS cores is another myth. New HB1 material has the similar saturation as typical grain oriented steel, what more noise level is at level of M2. The mass of three phase 400 kVA transformer amorphous core is no more than 10% bigger than the mass of the low losses traditional core.

Vishnu Dutta's picture

Having gone through the valuable comments of Mr Leander and Mr Jenkins, I have certain points to highlight.
Firstly I am in complete agreement with Mr Stefan Roman to the point that the lack of production capacity of amorphous alloys is a poor argument against a better technology.

I have worked in one of the largest establishments of amorphous core transformers plant and I agree that amorphous cores are no doubt more in size.

This does not mean that the copper windings used in the cores are more. The increase in size is due to

1) Flux Density limitation in the Commercial SA1 grade. But be rest assured that this is not as high as 50% more than the GOs even with the existing grade.  HB 1 will solve this problem once for all since even with the GOs and the existing latest CENELEC Specification a designer does not exceed the 1.55 Tesla levels. Isn’t it? Even with a laser scribed core.
2) Wound Core Construction for even the larger transformer which makes the length of the transformer slightly more than the conventional trafos since the cores are rectangular in size.

Flat stack core was a technology which was not attempted for amorphous cores. This was tried by Cooper Power. This is however not a constraint since we also have 10/12 MVA Transformers also with Amorphous Cores. It just matter of time which is required to establish a norm for these transformers to be manufactured. The entire process is demand driven. Necessity has changed everything and history is a witness to the same.
Mentioning materials either for core or windings have always been an impediment for achieving energy efficiencies. Using Aluminium instead of copper to meet the same losses as specified in the technical specifications does not have any disadvantage…aren’t they? Looking at the volatile copper prices, the potential ranges of these transformers in Europe (such as 100 to 400 kVA) are in fact economically feasible with Aluminium windings rather than that of copper windings. These windings are of foil type which is conventionally produced in Europe. Needless to mention that I have not come across a single copper promoter during my promotion tours to Europe for Amorphous Metal Transformers.

As far as the production capacity is concerned, there is not a single technology that does not go through this infant period (though it has been more than 25 years since amorphous metal was invented). It was only in the past 1 or 2 years that Amorphous Transformers has found inroads in Europe thanks to the climate change concern across the continent.

Hitachi’s production capacity is in line with the demand for these metals. In case there is an upsurge in this demand, I am sure that they would not hesitate to raise the production capacity. This upsurge will also not be all of a sudden as it is a time taking process. Hitachi has already added a capacity of 20000 MT this year in Conway, USA to meet the extra surge in Demand. Need arising am sure that this capacity will also see a jump in the production.

The rise in the demand of GO’s is due to the fact that the specifications across the world are changing for better efficiencies. CENELEC in Europe, DOE in the USA, BEE in India, TOP RUNNER in Japan are few to quote for. GO manufacturers may soon very well stop the production of lower grades of Core Steel such as M5 and M6 since the demand may and very well will drip to rock bottom levels. In countries such as China, they have gone ahead to procure only amorphous cores in certain public tenders in the Northern part. It is just a matter of time for the entire scene to change. The GO makers may very well have to invent something equivalent to amorphous or something better.

Now as far as Mr Leander views over the time of acceptance for AMDTs are concerned, please be informed that ENEL and ENDESA has already found these transformers feasible and they have huge projects lined up based on these transformers. Brazil which is one of the fastest growing countries have also accepted amorphous cores as one of the important part in their Luz Para Todos program. Sir, what I would like to mention is that the commercial viability of Super conducting transformers would take another 10 years and this time is more than enough for the AMDTs to find a place in the European and as well as major installations across the globe. In case European manufacturers are not adapted to this model, I am afraid that they would have to find a suitable way to adapt their technique for making these transformers. After all I guess this is what is called building the business model in synchronous to the climate change need of this globe. One very significant illustration would be that of the hybrid vehicles wiping out the ones which run on fossil fuels.

Major Economies probably need to work on certain definitive and time bound incentive packages for the manufacturers to promote energy efficiency. Green Tax proposal could be one such initiative which can prove encouraging for a manufacturer in this aspect.

Vishnu Dutta's picture

Loading of Distribution Transformers in India has remain a topic which is under debate.A neutral report on the loading pattern of Distribution Trafos would perhaps throw some light.

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