Short Summary fromsecond Meeting of the Ecodesign CF Subgroup on Large Power Transformers

Brussels 28-09-2012

• Distribution Transformers (medium PT)

• Power Transformers (Large PT)

REMARK:European Commission can only regulate the manufacturer and not the customer-side

of the transformer sale

Dustribution Transformers (medium PT)The minimum energy performance requirements for MPT consist of

maximum allowed load and no-load losses

Dustribution Transformers (medium PT)DRAFT of EN xxxx- to become a HARMONIZED standard

for ‘three-phase medium voltage transformers, with highest voltage of equipment not exceeding 36kV’

Possible obstacles• Production capacity of raw material (silicon and amorphous steel)

• Possible monopoly of raw material production

• Increased cost and prices

• Increased dimensions of products (it is often limited)

• Increased level of noise – environmental aspect! (residental and closed areas)

• Amorphous Metal Recycling System

• Different view on future energy price level between Norway and EU (SINTEF)

• Different interest rates within EU countries

• Political issue?

Power Transformers (Large PT)

The minimum energy peak efficiency level

k.S

k².P-)P+ (P -k.S=η

r

kc00r k².Pcosk.S

cosk.S=η

k0r

r

P

Energy Efficiency calculation

Conventional formula Proposed formula

EfficiencyThe efficiency is the ratio of usable energy on the output of a transformers over the supplied energy on the input of the transformers

The efficiency is maximal when no load losses equals load losses

k.S

k².P-)P+ (P -k.S=η

r

kc00r

Lossesdue to load

No load losses

Permanently on cooling losses

Supplied powerUsable energy

• For the purpose of EC regulation the formula has to :– Be simple and easy to apply – Be independent of rated power and definition of multi stage cooling– Be fair and non favoring any cooling type– Take into account all losses

• And therefore the retained equation is :– Based on apparent power in VA (cos φ =1)– The maximum efficiency one– With the losses corrected at 20 °C + Average winding rise

• i.e. 90 °C for OD cooled transformer• 85 °C for ON or OF cooled transformer.

– With the permanent cooling losses

Why use energy peak efficiency?• No expectation of load factor, so should be appropriate for a wide range of transformers• Compatible with procurement using loss capitalisation• Very difficult to make a transformer with poor core steel to meet minimum peak efficiency

requirement

And avoid problems when using maximum loss tables

• Flexibility is needed to accommodate different modes of operation• Transport problems will be even bigger Full load all the time Part loading (network etc.) Different levels of redundancy Different ways of specifying rating (Continuous rated or Emergency rated)

And therefore the proposed equation is:

PP+ P

S

) P+ (P 2.1-=η

k

c00r

c00max

.

Which correspond to load factor of:

P

P+ P=k

k

c00ηmax

Efficiency variation across load variation

• Efficiency dependence on load factor is small for usual LL/NLL ration

• For a ratio of 5 and 7.5 kηmax

occurs at 0.4

• Example given on the base of a 170 MVA

1. To collect data about the existing population manufactured in the last 10 years

2. To calculate EE expressed as shown3. To define the EE trend (for each class) 4. To define the minimum EE limit (according to the trend for each class)

Where to set minimum energy peak efficiency?Process flow with example:

T&D presented materials (Thomas Fogelberg and Giuliano Monizza, both from ABB).•represents requirements from customers around Europe which were part of tenders and purchasing documents. All data came from 8 LPTs manufacturers and from recent past

• huge difference between capitalisation factors values• Keep in mind that future Ecodesign Directive will be applied to all countries within EU no

matter at which level is their capitalisation (price of energy, interest rate, years in service…)• does it look harmonized?

Questions and issues:• what to do with long term MPT & LPT purchasing contracts with levels of losses above or

peak efficiency bellow than it will be proscribed within Ecodesign Directive?• How to quantify savings and what we are gaining if we install new LPT with higher efficiency

instead existing one? Money, Energy, CO2? Calculate in every specific case and then translate to CO2 emission 0,4kg/kWh?

• And again: Are energy prices and interest rates political issues?• VITO representative said that he agrees that project report does not cover all possible

options and consequences (transport problems, ability to replace DT and LPT and other constrains) but he repeated that project and study are based on 7 base cases and it was necessary to have same assumptions as well as to neglect something. Otherwise it was not possible to do it and it will be extremely complicated

Everybody will have only benefit except utilities, regions or countries which did not already implemented high capitalization of losses

during purchase process (see T&D table).

Conclusion about LPT