Transformers

Based on a Discussion Webinar, Friday, April 11th 2008

Losses in transmission and distribution networks represent the single biggest use in any electricity system. In Europe, they consume between 4 and 10% of electricity generated. What can be done to optimise the electricity system and reduce these losses? Which countries are setting a good example? And what is the role of regulation and policies on this point? Current tariff systems in most European countries are not really favouring network efficiency, and what about the influence of increasingly distributed generation on future network losses?

These and other questions were addressed in a Discussion Webinar on April 11th 2008. The following are a few of the major points arising from that discussion.

7% of the energy is lost in the network

The world average loss in the electric network system is 8.8%. However, this figure includes countries like India and Brazil, where the losses are high due to so-called “non-technical losses” – electricity which could not be invoiced and is mainly lost via illegal network connections.

…while outside the station the value already drops to less than 1% of that value, so no excession of any environmental limits!

By Angelo Baggini, University of Bergamo
& Franco Bua, Engineering Consulting & Design

In industrial plants, power transformers are expensive components of high strategic importance. Unavailability due to faults generally results in high costs, both in relation to repair work and in terms of lost production.

Efficient diagnostic monitoring capable of highlighting incipient faults and therefore able to reduce the fault rate and downtime of the transformer within considered physiological limits are generally of extreme interest for maintenance departments.

This article introduces a number of general considerations on fault statistics, and explains the main on-line diagnostic monitoring approaches.

Who's afraid of magnetic fields? And if so, who are the culprits? Probably those whose basic principle of working is magnetic fields – or rather not that much? This transformer has a magnetic stray flux of 37.8µT when measured right on top of the cover, where people should not walk anyway for a number of reasons ...

The SEEDT project organises a workshop in Brussels on January 31 at 13.45

The event takes place in the Metals Conference Centre (Montgomery, two metro stops from Schuman),
1150 Brussels,
100 rue du Duc,
5th floor, Nickel room

The workshop program will be:

14.15: Introduction, distribution transformer situation in Europe; populations, age, losses, efficiency, loading, - Roman Targosz
14.35: Energy efficiency and technology: traditional design, amorphous transformers - Endesa case, superconducting transformers - Juan Frau & Roman Targosz
14.55: Transformer - capitalized losses - standard limits?

15.15: Coffee break

15.30: Regulation. Policy - energy efficiency framework & measures relevant for distribution transformers; proposal of labelling Wolfgang Irrek / Roman Targosz
15.50: Saving potential / analysis of economic impact - Wolfgang Irrek / Roman Targosz
16.00: Guests contributions and discussion

We still have some free seats in the meeting room, therefore I would like to ask you to invite your colleagues who may benefit from or contribute to this workshop.

Please ask them to confirm it directly to Roman Targosz

LE3D is Leonardo ENERGY's virtual world on sustainable energy. For a flavour of the 3D world, view the slideshow below.

Join LE3D

The fourth (weekly) session at the Leonardo ENERGY 3D Forum takes place this Friday October 19, from 14h00 - 15h00 Europe Daylight Time, where you can meet with the Leonardo ENERGY team and other users of the Leonardo initiative inside the 3D forum.

During the session, you can power-chat (chat in parallel with multiple visitors), talk by VoIP, exchange business cards or browse the pavillons of the 3D world, which is updated weekly. The pavillions comprise virtual stands where you have access to information and 3D models of a number of appliances.

You are also invited to listen to past recorded presentations in the archive room.

For this Friday, following side presentations are scheduled during the session:

The social session will be followed by a webinar in Conference Room A by Ivan Benes on Energy Security and Critical Infrastructure Resilience. It should start around 15h00, European Daylight Time.

If you have not already done so, download & install the 3D World and register for the 3D Forum.

We hope to see you there regularly as our virtual guest in our weekly sessions every Friday, but you are invited to visit and investigate the Leonardo ENERGY 3D Forum at any time.

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By E Amoiralis et al

The goal of this article is to encourage electric utilities and potential investors to purchase and install high-efficiency distribution transformers where they are cost-effective. This paper proposes a methodology that implements the complex economic analyses needed to accurately determine the emissionreduction potential of high-efficiency distribution transformers. This methodology properly introduces the environmental cost into the life cycle cost (total owning cost) calculations implemented by electric utilities, and its results are compared to the classical total owning cost (without environmental cost), indicating the importance of environmental aspects of transformer economy evaluation, which may affect significantly the currently-employed transformer purchasing policy in the near future. Moreover, a sensitivity analysis of the various factors involved in the transformer life cycle cost is implemented, factors such as the transformer loading profile, the specific characteristics of the network where the transformer is installed and the uncertainty of the environmental cost impact on the final energy.

View paper (pdf)

By Roman Targosz et al

Losses in distribution transformers account for almost one third of overall transmission and distribution losses. Previous European Copper Institute studies indicated that improving energy efficiency of existing European stock of transformers by 40% would result in about 22 TWh energy savings equivalent to about 9 million tonne of CO2eq. SEEDT is one of the projects developed under Intelligent Energy – Europe programme which converts EU energy policy for today’s energy challenges like energy efficiency. One the main goals is to update and scrutinize knowledge about energy efficiency in distribution transformers in Europe. This paper presents findings of analysis of existing situation.

View paper (pdf)

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The Leonardo ENERGY team is a group of individuals dedicated to sustainable energy.

The Leonardo ENERGY 3D Forum is a highly innovative virtual environment for meeting & interacting with peers.

From this Friday September 28 onwards, from 14h00 - 15h00 Europe Daylight Time, you can meet weekly with the Leonardo ENERGY team and other users of the Leonardo initiative inside the 3D forum. We will animate the forum with short presentations, you can power-chat (or talk by VoIP) with us or others, exchange business cards, or browse the pavillons of the 3D world.

We will repeat this event weekly, on Fridays, while adding more content. Mark some of the future dates on October 5, 12, 19 and 26.

On selected Fridays, the social session at 14h00 will be followed by a webinar at 15h00. We already have 2 speakers lined up:

• On October 5, Angelo Baggini will explain resilient wiring architectures
• On October 26, Stefan Fassbinder will give the latest insights into copper motor rotor technology

If you have not already done so, download the 3D World, install it on your PC and register for the 3D Forum. We hope to see you there regularly as our virtual guest.

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Many new publications have been added to the eLibrary since February, bringing the total number of application notes, briefing papers, reports and presentations to 195, or almost 3,000 pages. Run the autoupdater to synchronise your files.

If you are new to the Leonardo ENERGY eLibrary, click here to obtain the autoupdater.

New publications cover application notes on distribution generation, renewable energy and energy efficiency. Articles have been added on lighting, flow batteries, fire proof cable and amorphous transformers. Three new reports from the power quality regulation project have become available, and a new eco-sheet demonstrates the impact of energy efficiency in various electricity systems.

The population of distribution transformers in Europe is about 4,5 million units. The annual market; new investments and replacement, is estimated at about 3% of existing stock of units.

The overall population of EU-25 utility distribution transformers is estimated at 3,6 million units. Table and the figure below present the utility summary on EU-25 countries and Norway. Both the number of installed transformers and their average rating is given. Population of privately owned (usually referred to as industrial) oil filled distribution transformers installed in EU-25 is estimated at 800 thousand units with 400 kVA average transformer rating. The number of privately owned dry type transformers is estimated at less than 200 thousand units but the average rating is more than double of oil private fleet i.e. slightly more than 800 kVA.

Next figure presents the transformer size (ratings) in kVA relative distribution in population. All three sectors; utility, industry oil filled and industry dry type are covered. It is visible that utilities operate lower ratings especially in rural areas while industry and particularly dry type transformers have much higher ratings in average.

SEEDT - Strategies for development and diffusion of Energy Efficient Distribution Transformers

SEEDT is one of the projects developed under Intelligent Energy – Europe programme which converts EU energy policy for today’s energy challenges like energy efficiency. The aim of this project is to promote the use of energy efficient distribution transformers, which can be profitable for investors, and by contribution to European Community energy saving potential, may help to fulfill EU energy policy targets. Strategies will include proposals for labeling, mandatory standards or voluntary agreements and development of different dissemination mechanisms. http://www.seedt.ntua.gr/

Distribution transformers are devices which transform electrical energy supplied at medium voltage level (typically from 10 kV to maximum 36 kV) to electrical energy at voltage level most appropriate for residential, almost all commercial and partly industrial loads (most typically 400 V 3 phase system, in general up to 1 kV e.g. 690V).

The scope of the project and SEEDT study covers distribution transformers in Europe, both utility owned and private. Distribution transformers operated and owned by electricity distribution companies are responsible for supplying about 70% of low voltage electricity to final users and represent about 80% of distribution transformers stock.

Transformers in general belong to the group of most efficient devices. However transformers, unlikely other electrical machines and systems, are responsible for supplying electricity to all final consumers, in multiple steps. In typical utility situation distribution transformer is the fourth step of voltage transformation. Thus, in case of transformers energy efficiency is of very high importance.

Europe is highly diversified in electricity distribution business, both in technical matters and structure. There are no mandatory standards or other measures effectively supporting use of energy efficient distribution transformers and SEEDT is going to present the existing situation in details.

Early this year, there was a call across the stakeholders for higher efficiency standards for distribution transformers in the U.S. The intention is to target more than 40 million units with the potential to save 26 TWh on an annual basis. Of course, one could always argue that since they present a clear case,  such a change will also be profitable; they should just do it themselves without asking for government involvement, but a government endorsement could not hurt.

However, large bait attracts fish and provokes a catch! Now, ABB in the U.S. has announced their support for this change to energy efficiency. It would not be surprising if more manufacturers follow this lead.

If this market really starts to move, could there be a niche for even more advanced transformer technologies, like the Hexagon transformer? They claim that it is possible to reduce losses by 50% and weight and volume by 30-40%.

The SEEDT project team invites you to a mini-poll (3 questions) on advanced technologies for distribution transformers. Thanks for your input!

Take survey

By Eiken Shibata, NAMCO

In Japan about 16 million units of distribution transformers are in service. These transformers are expending a huge amount of energy in the form of “no load loss” and “load loss.” Among these losses, “no load loss” is major. “No load loss” can be saved dramatically by changing these transformers to “amorphous transformers” (i.e., amorphous metal-based transformers). This paper estimates the scope of the possible energy saving and reduction of CO2 emissions by the adoption of “amorphous transformers” in Japan and in China.

28 February – 2 March 2007, Wels, Austria

The World Sustainable Energy Days are claimed as the largest annual conference in this field in Europe. It offers a unique combination of events on sustainable energy production and use, covering energy efficiency and renewable energy sources for buildings, industry and transport.

Leonardo ENERGY was present with a paper and presentation on ‘Network Efficiency Improvements’. Sergio Ferreira presented a brief overview of the losses in electricity distribution networks (estimated at 1279 TWh/year, worldwide) and some possible solutions to mitigate them. These focused on increasing the use of efficient distribution transformers in the grids, a solution that, alone, has an estimated savings potential of 200 TWh/year worldwide.

The paper and presentation include an analysis of the economic aspects of transformer purchasing, demonstrating that payback times for this type of investment are considerably short. This would be even more significant if coupled with adequate regulatory incentives for efficiency investments.

By Arjen G Jongepier, KEMA Consulting

Download briefing paper

The components of electricity networks are ageing. It is expected that within a horizon of 15 years, the performance will deteriorate significantly, while the costs for operating the networks will increase enormously. The main problem is that a significant part of the population of the assets is installed in the same period, resulting in a highly concentrated number of failures in a short time. The currently applied replacement strategy has to be revisited, in order to accommodate the effects of ageing assets: higher maintenance costs, high failure rates, and a steep increase of capital expenditure (CAPEX).

Methods like long-term simulation, multi-criteria decision-making under uncertainty, critical asset identification, condition assessment, and advanced statistics for the extrapolation of condition assessments of representative samples of assets should be applied. By using these methodologies in a smart and integrated way, costs and performance can be kept at an acceptable level.

Related

Managing risks in ageing networks: a case study

The purpose of this report is to show the influence of fluctuating loads and energy price on the economic optimum for distribution transformers. Two cases are considered: an economic study based on historical data from the forward market, and an economic study inth the A and B factor for wind turbines based on historical data for wind-speed and a given wind turbine characteristic.