Dear readers,

Again Transformers Magazine brings you a wide range of technical articles and two columns.

In his column Carlos Gamez reviews the most important factors that determine a transformer’s longevity and explores which actions a transformer owner, operator and maintainer can
take in order to manage and, as much as possible, extend the life of the important and expensive assets.

Omar Ahmed and Anne Goj analyse the activation of two mechanical depressurisation devices, the transformer protector and the pressure relief valve during an internal arc on a 400 MVA
three phase transformer. Authors performed computational simulations to study the dynamic pressure evolution and static pressure build up inside the tank.

Michel Duval presents challenging findings regarding the widely accepted criterion for end of life for paper insulation of paper DP of 200 being too high, and that it could be decreased to about
100 or even lower. In this way, the life of transformers could be extended by several years without increasing their risk of failure due to the mechanical condition of paper, thus significantly reducing capital investment costs needed for their replacement.