Insulating liquids in power transformers provide insulation, cooling and protection. But they can do even more - namely provide information about the "state of health" of the transformer. This requires regular professional sampling and analysis of oil samples. After all, the more regular the testing, the more accurately trends can be identified and problems solved at an early stage. Oliver Reetz is an expert for intelligent sensors at MR and knows what issues operators are dealing with in times of staff shortages and voltage fluctuations caused by renewable energies. In an interview with Christian Schaider, he talks about his experiences and how intelligent technologies can provide support.