Ester-filled distribution transformers

Ester-filled distribution transformers

Vol. 9 Issue 1

The sustainable model to strengthen the low voltage grid


The distribution transformer is a key piece of electrical equipment installed in our electrical network but with a substantial impact on the network’s overall cost, efficiency, and reliability. Selection and acquisition of distribution transformers are hence critical. Over the last 20 years, the acquisition processes for distribution transformers have moved in the right direction, with utilities becoming aware of the consequences of distribution transformer losses. New technical specifications such as IEC 60076-20 [1] on energy efficiency have been published, and many end-users (utilities) have started to incorporate the loss evaluation procedure. Contrary to this, there are still many end-users who rely on purchasing transformers based on the initial cost.

Read the full article in PDF


When such purchase requests are made, transformer manufacturers have little incentive to design energy-efficient transformers or provide innovative solutions. With the increasing numbers of new distribution transformers added every year, the need to get the selection and acquisition of distribution transformers correct is becoming crucial. This is amplified by the fact that as we move towards new types of load such as Electric Vehicles (EV), Distributed Energy Resources (DER), the need to increase the reliability of the network will become supercritical. The question would be – how much higher sized transformer would be appropriate to maintain network reliability? Larger transformers would have higher no-load losses, as well as higher mineral oil requirements, and would need more maintenance budgets to maintain the reliability of the network. Higher losses and more mineral oil would contribute to a greater carbon footprint!

To read the article, subscribe and choose the option which suits you best. We offer both free and paid options, and the registration takes only a minute.