TRANSFORMER'S MOISTURE ASSESSMENT WITH ONLINE MONITORING

This paper discusses the application of online moisture monitoring of operating loaded transformers. Real-time monitoring offers many benefits the fleet operator can achieve that are discussed below and shown as data examples from operating transformers. The data collected in this paper also shows the varying moisture patterns of different transformers, proving them to be very individual depending on their loading and maintenance history. Water solubility of two aged oil samples was defined to illustrate the effect of oil ageing. The many uncertainties related to the traditional method to define paper moisture from oil samples by applying moisture equilibrium charts are discussed on a general level.