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How much does your transformer really cost?

by Scriba PR

How much does your transformer really cost?

In line with the government’s latest energy targets, we have carbon reduction and power saving at the forefront of our activity here at Smith Brothers – and are constantly looking for new ways to help customers save money via energy reduction schemes.

With the latest legislation relating to transformer ‘losses’ or ‘lost energy’ set to come into force in 2021, we thought we’d take the opportunity to increase awareness of the costs associated with running old – and highly inefficient – distribution transformers, as well as just how much your substation(s) may be costing your business.

Commission Regulation (EU) No 548/2014

In operation, transformers produce heat because of current flow within the conductors and a magnetic flux circulating around a magnetic core. Over time, transformers become less efficient, and produce more heat, which is classified as ‘waste’. In short, the higher the loss, the less efficient the transformer.

Transformer Regulation No. 548/2014 imposes reduced levels of losses for transformers “placed on the market” or “put into service” after 1 July 2015 – within the EU. It has been published in the Official Journal of the European Union and came into force on 11 June, 2014.

Most ‘Pre-2014’ transformers are manufactured to an undetermined efficiency level, and the industry will often refer to these as ‘standard loss’ transformers.

As of 2014, the minimum requirement is a ‘Tier 1’ level of efficiency, with further regulations set to be imposed in 2021 – alongside a ‘Tier 2’ which determines an improved efficiency requirement for newly manufactured transformers.

Understanding transformer losses

‘No load losses’ arise within the magnetic core of a transformer and occur due to the energy consumed as part of hysteresis and eddy currents within the material, as it is taken through its alternating cycles of magnetisation.

The transformer’s magnetic core comprises of thin laminations of core steel, each of which has a coating of insulation to reduce the eddy current build-up within the complete core. The characteristics of heat output varies based upon the grade of material used and the working flux density.

There are two ways of reducing such losses within a transformer:

1) Reduce flux density by increasing the cross-sectional area of the magnetic core

2) Use higher grades of core steel to decrease the watts/kg for a particular flux density.

The ‘no load losses’ of a transformer is a constant loss and does not vary with load.

‘Load losses’, meanwhile, arise mainly as a result of the resistance within the transformer windings – produced by the flow of load current.

Increasing the copper or aluminium cross-sectional area within a winding has the effect of reducing its current density, which can lessen the losses. The load loss of a transformer varies to the square of the load.

Below is a comparison of the ‘no load losses’ and ‘full load losses’ of an 800 KVA ‘standard loss’ transformer, 800 KVA Tier 1 transformer and 800 KVA Tier 2 transformer:

‘Standard loss’ 800 KVA transformer:

• Estimated no load losses (these losses are continuous): 1150 Watts per hour • Estimated full load losses: 11,000 Watts per hour

‘Tier 1’ 800 KVA replacement:

• No load losses: 650 Watts- (500 Watts per hour saving)

• Full load losses: 8400 Watts – (2600 Watts per hour saving)

‘Tier 2’ 800 KVA replacement:

• No load losses: 585 Watts per hour – (565 Watts per hour saving)

• Full load losses: 6000 Watts per hour - (5000 Watts per hour saving)

(Load losses above are applicable to fluid-filled transformers)

Monetary savings If the above fills you with dread, fear not. There are several variables which could affect the lost energy within a transformer and how much direct cost applies to the overall running of the unit.

That’s why we’ve made it our mission to educate our clients – and beyond – around the benefits of upgrading their distribution transformers, and how a site survey could help. Factors we will consider include:

• Transformer size (kVA)

• Average load

• Nature of load

• Number of transformers

• Cost of energy (per kwh)

• Age of the existing infrastructure

This information then allows us to indicate, in monetary terms, the savings that could be achieved against the costs of procurement and installation of a replacement transformer.

For further information, or to request an initial site survey, contact business development & sales manager, Ben Whitaker on: 07387 1083 77 or email We would be happy to help!

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