75 MVA converter duty transformer After publishing several theoretical articles on VFD duty transformers it is time to have a closer look at some real designs. In today’s post we present a brilliant example: 75 MVA converter duty transformer designed according IEC 60076 standard. This transformer is supplied from 110 Read more
Testing of Converter Transformers This post discusses some aspects associated with testing of converter transformers. Most tests performed on converter duty (VFD) transformers are same as those specified for power transformers. However, there are also few differences which are highlighted in corresponding sections of this article. The aim is to Read more
Tap changer: Yes or No? Shall a VFD transformer be equipped with a tap changer? What are the pros and cons of a tap changer on converter duty transformer? What kind of tap changer shall be used? How many taps does the VFD transformer have? This and more in our Read more
VFD transformers: Differential protection Differential protection of VFD transformers might be a controversial topic. The more a reason for us to bring it up, explain the principle, describe the advantages and drawbacks and provide our view and recommendation for the users. We hope that this article will be useful source Read more
VFD transformers: Your questions The articles from VFD transformers [1] series belong to the most frequently read posts in our blog. It seems that many visitors find us through internet search using keywords such as “converter duty transformer”, “24 pulse drive phase shift”, “extended delta transformer”, “12-pulse phase-shifting transformer”, “three Read more
Overvoltage protection of transformers This is the continuation of [1] that made an introduction into protection of VFD transformers. The focus of this article is on overvoltage protection. Particular attention is paid to very fast transient overvoltages caused by switching of vacuum circuit breakers. Keep reading to learn about the Read more
Combined transformer Our recent post [1] walked the reader through the two main VFD transformer options: integrated transformer and external transformer. Today we will introduce a solution that aims to leverage on advantages of both solutions: combined transformer. The name might be a bit misleading. We can also call it Read more
VFD transformer rental This post provides a brief description of our service “VFD transformer rental”. You will learn what the service is about, how it works, what is the target application etc. The contact form is located in our section Services (click here). Introduction Transformers are mainly used in power Read more
VFD transformers and harmonics Introduction The next post in our series discusses VFD transformers and harmonics. We have already learned what harmonics are and how they impact the supply grid (Network harmonics – intro). In this series we look more specifically into harmonics and their impact on VFD transformer. Motivation Read more
VFD transformers: Multi-winding design Today we look at the design of multi-winding VFD transformer feeding variable frequency drives. These VFD transformers are often classified in the category of ‘special transformers’. What does it mean? Why are they special? If you want to get these answers and a little insight into Read more