Column: Water in transformers

Column: Water in transformers

All you wanted to know about it, but were afraid to ask

1. Q&A about water in transformers

The idea to write a Q&A column about water in transformers for this magazine came from various speaking and consulting engagements. Very often during seminars, workshops or technical presentations I have been asked to explain and elaborate on ‘seems to be trivial’, but ‘appeared to be’ complex phenomena, statements or a fact related to presence and effects of water in transformers.

Water in transformers is an intriguing topic and usually attracts an interest of large groups of professionals in the field of high-voltage electrical equipment operation and maintenance. From the onset of transformer manufacture, drying of solid and liquid insulation presents an operational and technical challenge, consuming a lot of effort and resources. Even after a thorough job on drying, water finds its way into a transformer taking every possible path during its transportation from factory floor to the final destination. Water is often labelled as the worst enemy of transformers and numerous research papers have been published covering this uneasy subject. Water is the source of all life on our planet, but in transformers, this is one of the major life-threatening substance. Here comes the first question.

2. Water in transformers – So what!

This was the title of a paper written by Paul Griffin of Doble Engineering Co in 1996. The paper summarises some detrimental effects of water on transformer insulation and, in particular, the author focuses on reduction in dielectric strength of liquid and solid insulation, evolution of gas bubbles and accelerated ageing of transformer insulation, both paper and oil.