Condition of cellulose insulation in oil immersed transformers after factory acceptance test

The purpose of this brochure is to provide the industry with a guide for checking material properties of cellulose insulation at the point when the transformer leaves the factory. The report covers the selection of relevant acceptance parameters, simulations of the relative influence of these parameters and suggested acceptance criteria. It also covers how to measure these parameters. Focus has been to define parameters that have a direct effect on the transformer insulation lifetime, that are measurable and where achievable limits can be defined and set.